n
SHOP MANUAL
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PRINTED IN JAPAN
Bt 17401 &H A50508MI C
r
C70
GENERAL INFORMATION
TOOLS
SPECIAL
Tool Namit Tool No. Q'ty Ref. page
Veiw (fuidf teamer 07984 0980000 1 6-8. 6-9
Flywheel holdc 07922-1290000 1 14-7,14-8
. Commercially available band strap v/rnech mav bo used
8aH race romovet 17946 1790000 M9310-277-91774 (U.S.A. only* 1 12-18
Pin spam**'. 36 mm 07907-0010000 1 1217.1219
Valve guide driver 0794? 1180100 1 6-9
COMMON
Tool Name
Float level gauge
Valve guide remover 5.5 mm
Universal holder
Valve adjuring wren*. 8x9 mm
Valve ad|u«ing wench, 8
Lock nut .viench, 26 x 30 mm
Extension Dor
Rotor pulMr
Beating ririvor hiinrile, A
Bearing driver outer. 32 x 35 mm
Bear Ing driver Outer. 37 x 40 mm
Bearing drive* pilot. 10 mm
Bearing driver pilot, 13 ran
Bearing drivei pilot. 17 mm
R*o' slwck absorber compressor
Nipple span not 8, 4.5 x 5.1 mm
Valve spring mmiHcssoi
Lock nut wrench. 20 x 24 mm
Tool No.
07401-0010000
077420010100
07725-0010101
0770BOQ3O10O
07708-0030400 U.S.A. only, roftr to
S.T.N. No. 47
077160020202
077160020500 07733-0020001
077490010000 07748-0010100
07746-0010200
077460040100 07746-0040200 077460040400 079593290001 077010020700 077570010000 07716-0020100
a
Alternate Tool
Valve guide removal
Clutch liokitii Commercially avail a We 8 x 9 mm offset box-end wrench
Commercial available
Removing bo'l Drivttr handle
Bearing driver attach Bearing driver attach
Tool No
V.-ilve spiles compreswi
07942 3290100 07923-0400000
90015-360-000
07949-6110000
O7949-3O0OO0C
079469370100
07945-0980000. 37 mm
07946-3000000, 40 mm
0795/-379000!
Ref.
45
6-9
8-3, 8-6
3-0
3-6
8-3
83
14-7
129. 134. 13-9
129
12-9
13-4
13-9
13-10. 13-11
3-18
6-5.6-1»
8-3. »6
Daie of tssuo: May, 1980 ©H0NOA MOTOR CO., LT|>.
1-5
•MPORTANT SAFETY NOTICE
_X^tlhU*i£l """tw a ffiong poxslblllty »f mrre personal injury or last of life if instructions not fotltiweti.
CAUTION: httlinwt a pnmhtHry af psrw'l Injury o' equipment damage if initrttctiont art nor foB&uviS.
Detailed dMO-iptlons of standard workshop procedures. safely principles, oid ioc-iq! operation! oto not included. It li ImpGrtnn io note that this manual coma'"* some warningi nod cauiiom against some specific wmice method! which wuld caw PERSONAL INJURY to wivice peimnnel or nuld nemaip ii -ehicte 0' tender it unwi'e. P*a&a underiiand thai those warnings could r"' cover all conceivable ways "i which service, whether or not rGcommerviM i.y Honda mioht be done o> of tne pooiole hazardous smsequences of each conceivable way, nor could Honda mvasii&ate all such ways. Anyone 011119 wvioo procedures or tools, whether or not recommended Dy HONDA must satisfy himtetf thorougtily that neither personal safry nor vehicle safety will be jeopardi/ed hy the service mtthods o' tools ulncied.
GENERAL INFORMATION
HONDA C70
CABLE & HARNESS ROUTING
LEFT HANDLEBAR SWITCH HARNESS
THROTTLE CABLE
CLAMPS
FRONT BRAKE CABLE
RIGHT HANDLEBAR SWITCH HARNESS
CHOKE CABLE
A.C. GENERATOR WIRE
CLAMPS
1-6
iiieot liiue: May. 1980
i HONDA MOTOR CO.. LTD.
HOW TO USE THIS MANUAL
'
Follow the Maintenance Schedule recom mendations to ensjre tliat the vehicle is always in peak operating condition, performing Hie first scheduled maintenance is very important. It compensates for the initial wear that occurs during the break-in period.
Sections I through 3 apply to the whole motorcycle, while sections 4 through 17 describe p8rts of the motorcycle, grouped according to locatlor.
Find the section you want on this page, then turn to the tabic of contents on page 1 of that section.
Most sections start with an assembly or system illustration and specifications, torque values, general instructions, cools and troubleshooting for the section. The subsequent pages give detailed p-ocedures for the section.
If you don't know lie source of the trouble. see section 18, TROUBLESHOOTING.
Refer to the addendum at the back of the shop manual for irformation on the 1982 C70.
ALL INFORMATION. ILLUSTRATIONS. Dl RECTIONS AND SPECIFICATIONS INCLUDED IN THIS PUBLICATION ARE BASED ON THE LATEST PRODUCT IN FORMATION AVAILABLE AT THE TIME OF APPROVAL FOR PRINTING. HONDA MOTOR CO,, LTD. RESERVES THE RIGHT TO MAKE CHANGES AT ANY TIMB WITHOUT NOTICE AND WITHOUT INCURRING ANY OBLIGATION WHATEVER. NO PART OF THIS PUBLICATION MAY BE REPRODJCED WITHOUT WRIT TEN PERMISSION
HON3A MOTOR CO.. LTD. Service Publication* Office
GENERAL INFORMATION
LUBRICATION
INSPECTION AND ftDJUSTMFN"
FUEL SYSTEM
ENGINE REMOVAL/INSTALLATION
CYLINDER HEAD/VALVE
|l
CVLiNDER/PISTON
to
i
<
5
CLUTCH
GEARSHIFT LINKAGE
TRANSMISSION/CRANKSHAFT
CAM CHAIN TENSI3NER
FRONT WHEEL/SUSPENSION
REAR WHEEL/SUSPENSION
BATTERY/CHARGING SYSTEM
IGNITION SYSTEM
ELECTRIC STARTER
SWITCHES
TROUBLESHOOTING
WIRING DIAGRAM
m
'82 C7Q ADDENDUM
Dale of Issue: Nov., 1981
© HONDA MOTOR CO,. LTD.
C70
GENERAL INFORMATION
~
THROTTLE CABLE
SPEEDOMETER CABLE FRONT BRAKE CABLE -
IGNITION COtL
RECTIFIER
TURN SIGNAL RELAY
BATTERY
Daieofhsuc: May, 1SS0 ©HONDA MOTOR CO.. LTD.
1-7
C70
MODEL IDENTIFICATION
«<
r f
O
The frame wrial number la Damped on ihe frame'* l-oli ii dc ccoiiti^cn ov am ii iTunrjiTtr i iirtMUfl r iCAl fcP IIIU 1 CVC IMC ftlAIMCP MA< : rr apc: l
NOTE:
TOOLS AND SERVICE DATA AND IS MECHANICALLY QUALIFIED.
IN THE INTEREST OF SAFETY, WE RECOMMEND THESE ITEMS BE SERVICED ONLY BY AN AUTHORIZED HONDA DEALER.
1. SERVICE MORE FREQUENTLY WHEN RIOING IN DUSTY AREAS.
2. SERVICE MORE FREQUENTLY WHEN HIDING IN RAIN OR AT FULL THROTTLE. (U.S.A. ONLYI
3 FOR HIGHER ODOMETER READINGS. REPEAT AT THE FREQUENCY INTERVAL ESTABLISHED HERE.
1-8
10
Dateollssue; May, 1980 RHONDA MOTOR CO.. LTD.
C70
1. GENERAL INFORMATION
GENERAL SAFETY 1-1 CABLE & HARNESS ROUTING 1 1-6
SERVICE RULES 1-1 MAINTENANCE SCHEDULE 1-8
SPECIFICATIONS 1-2 EMISSION CONTROL SYSTEM 1-9
TORQUE VALUES 1-4
TOOLS 1-5
GENERAL SAFETY
n,
BBB
If the engine must be running to do some work, make sure ihe area Is wB-rmiilated, Mmt run the engine In a closed area- The exltauu contain! poisonout carbon monoxide gas.
fi> WARNING
Gasoline Is extremely flammable and It explosive under certain conditions. Do not smoke or allow flames or sparks m your working area.
% WARNING
The battery electrolyte contains sulfuric acid. Protect your eyes, akin and clothing. In case of contact, flutJi thoroughly with WW and call a doctor if electrolyte gets in your eyes.
»¦ WARNING
The battery genetnm hydrogen gas which can be highly explosive. Do not xmoke or allow flumes or sparks near the battery, especially ohde charging it.
"
SERVICE RULES
""
1. Uw genuine HONDA or HONDA-recommended parts and lubricants or their equivalents. Parti that don't meet Hondo's design spedficarions may damage the motorcycle.
2. Use the special tooli deigned for this product.
3. Use only metric tools when servicing this moiorcycio. Metric bolts, nuts, and tcrnws are not Interchangeable with English fasteners. The use of incorrect tools and fasteners may damage the motorcycle.
4. Install new gaskets, O-rinQS, cotter pins. lock plates, etc. when reassembling.
6. Ween tightening bolts or nuts, begin with the larger -diameter or inner bolt flr*t, and tighten to the specified turque values diagonally m 2-3 steps, unless a particular sequence is specified.
6. Clean larii in nonflammable or high Mash point solvent upon disassembly. Lubricate any sliding surfaces before reassembly.
7. After reassembly, check all pats for proper installation and operation.
Dateot Issue: May. 1980 ©HONDA WOTOR CO.. LTD.
1-1
1
~
%
C70
GENERAL INFORMATION
EMISSION CONTROL SYSTEM
The CO is enuipotil with lean carburetor setting* and other systems to reduce carbon monoxide and hydiocartxin amissions.
EXHAUST SYSTEM
Ths exhaust emission control synem is composed of lean carburetor setting*, and no adjust menu shuuld be made except Idle
sp^eo1 adjustment wilh. ihe throttle imp tuew.
The exiwiiM emission control system is separate from the cankcase emission control system.
CRANKCASE SYSTEM
The engine ii equipped with a closed crankcaw system to prevent discharging ertmkease emissions into the atmosphere. Blow-by gas is returned 10 the combust km chamber through ths air cleaner and Ihe carburetor.
Fresh Air Blow-By Gas
INFORMATION LABEL
The Emission Control Informalnn label in looted on the nvlngarm left side.
Vehicel Emission Control Informaion Lsttri
Date of Issue: May, 1980
£) HONDA MOTOR CO., LTD.
11
1-9
GENERAL INFORMATION
C70
SPECIFICATIONS
ITEM
DIMENSIONS Overall long!" 1,805mm 171.1 in|
Overall width 665 mm {26.2 inl
Overall height 396 mm 139.2 inl
Wheelbese 1.180mm 146.5 tn)
Seat height ?60mm 129.9 in|
Pooipeg heigl'i 260 mm (10.2 ml
Minimum ground duomncc 130 mm | 5.1 ln|
D'v weight 83.5 kg 1184101
FRAME Type Backbone
Front suspension, travel Leading-Link 55 mm 12.2 in)
Rear iuspent ion, navel Swingarm 60 mm {2.4 in)
Fiom tire ii;e. pressure 2.25-17-4PR 2.0kfl/cm: (28ptil
Rear lite use. pressure 2.50-I7-6PR 2.B kg/cm' (40 p*l
Fiont Iwnhi* C.ililc appr.ileti leadirKj vN>e
Hear brake Kod operated leading shoe
Fuel rapacity 4.0 lit 11.05 US gal. 0.88 Imp gal)
Fuel reserve capacity 0.8 lit (0.21 US gal. 0.18 Imp gal)
C«tt« angle 64°
Trail 70 mm |2.8 In)
ENGINE Type Air cooled 4-sIfoke
Cylinder of range mem Single, inclined 80° Irom vortical
Bore ana ttroke 47.0 x 41.4 nun (1.85 x 1.63 in)
Displacement 72 cm' (4.4 cu inl
Compression ratio 8.8:1
Valve train Chain driven overhead camshaft
M exi mu m horse power 5.0 8HP/7.000 rpm
Maximum torque D.56kfl-m/5.500rpm
Oil capacity 0,7 lit (0.74 US qt, 0.62 Imp qtl after disassembly 0.6 lit (0.65 US qt. 0.53 Imp qtl aftei draining
Lubrication sysiem Forced pteuure and wet sump
Air filtration Paper
Cylinder compression 12.51 0.5 kg/on' (l78t7psiJ
Intake valve Opens 0" BTDC -i
Clow* Exhaust valve Opens &»«<—
Glow SnATDCJ
Valve clearance iCoidl IN: 0.05 mm (0.002 Id)
EX 0.06 mm 10.002 In)
Engine weight 18 kg (39.7 lb)
Idle speed 1,5001100 rpm
CARBURETION CarDuretot type Piston valve, 14 mm (0.55 m| vcnturi bore
Identification number 'B0r P832A "81 PB32C
Pilot screw initial setting See page 4-7
Float level 10.7 mm (0.42 in)
1-2
Date of Issue: May. 1980 ©HONDA MOTOH CO., LTD.
LUBRICATIUQN
C70
ENGINE LUBRICATION SYSTEM
OIL PUMP
,CYLINDFR
CVLINOEH
HEAD
-.RIGHT CYLINDER HEAD COVED
CAMSHAFT -*-CRANKCASE
HIGHT CRANKCASE COVER
CLUTCH
ADJUSTING
BOLT
CENTRIFUGAL OIL FILTER
-CRANKSHAFT
CRANKCASE
2-0
12
Date of Itsue: May, 11 ©HONDA MOTOR CO.. LTD,
C70
GENERAL INFORMATION
O
ITEM
DRIVE TRAIN Clutch TrafiiRiiswofi Primary leducilon Final reduction Gear ratio 1 Gear ratio II Gear ratio III Wet mu Hi-plate automatic centrifugal 3-specd constant mesh 4.068 3.571 3.272 1.722 1.190
Gaarshifi pattern Left loot o Flywheel n permed return *yMemN-1-2-3
ELECTRICAL Ignition ogneto
Point Rap Ignition timing "f" mark Full advance Stalling system Generator Battery capacity Spark plug 0,3- 0.4 mm (0.012-0.016 in) 1 B; BTOC, Static 30' BTDCat 3.100 rpm Kick turtor and itwler motor Flywheel A.C. generator 57 W/5.CO0 rpm 6V-11 AH ICANADA)
Fot »ld climate »¦>« . n» Fa> extended high
bek>w5"C,4l0F oi -n^Hnu speed operation
ND NGK ND NGK ND NGK
U20FS C6H U22FS C7HS U24FB C9H
1U30FSR ICR6HS) IU22FSR •L| ICR7HSI IU24FSR LI ICR8HS1
Spark plug gap Fuse capacity 0.8 - 0.7 mm 10.024 - 0.028 InJ 10 A
LIGHTS Headlight (high/low boa ml Tail/Ropl CENTRIFUGAL OIL FILTER CLEANING 2-3
ENGINE OIL LEVEL 2-2 OIL PUMP 2-4
ENGINE OIL CHANGE 2-2 LUBRICATION POINTS 2-7
SERVICE INFORMATION
GENERAL INSTRUCTIONS
Oil filler screen and oil pomp inspection and maintenance can be made without, removing the engine,
SPECIFICATIONS
STANDARO
SERVICE LIMIT
Engine oil capacity
Recommended oil
Oil pump
Tip tfeeianoe Bodv clearance End clearance
Approximately0.6 liter (0.65 USe
ENGINE OIL LEVEL
Support the motoicvclo upright on level ground. Chuck Iho oil level with the lilfet cap/dipstick. Do not screw in the cap when making this check. U the level b below the lower level on the dipstick, till to die upper level maik with the recommended engine oil.
ENGINE OIL CHANGE
NOTE
When changing the oil, drain the used oil from the crankc&ic while the engine n warm. This ensures complete and rapid draining._________
Remove the oil filler cap/dipstick.
Plan an oil drain pen under iho engine, and remove the drain plug. When the oil has been completely drained, bo sure that the drain plug sealing washer is In good condition and Irtttnll the drain plug.
TORQUE: 2-0 - 2.5 kg-m (14 - 18 ft-lb)
Pour the 'eemmended nit (pegs 2-11 slowly through
the oil IIIte. hole.
CAPACITY: 0.6 liter (0.66 US qt) ae oil change
Install the nil tiller rap'd-pitick. Start the engine and let it Idle 2-3 minutei. Stop the engine and check thai the oil level is at the upper level mark on the dp stick with the motorcycle upright. Check that utsra 8'* no oil leaks.
OIL FILLER CAP/DIPSTICK
UPPER
LEV El
LOWER LEVEL
DRAIN PLUG
ENGINE OIL FILTER SCREEN CLEANING
NOTE
Perform this maintenance with the engine Oil dislned,
Remove the front cover lower righi mounting bolt. Remove the kick startet pedal and mu liter. Support the motorcycle with a suitable stand and remove the tool pegs /side stand assembly. Remove Ihe 'ight u:inkc#se covet,
RIGHT CRANKCASE COVER
FRONT COVER LOWER RIGHT MOUNTING BOLT
MUFFLER KiCK SORTER PEDAL FQQTPEGS/SIDE STAND
2-2
14
Oatoof Issue: May. 7980
© HONDA MOTOR CO.. LTD.
~
s
C70
LUBRICATION
"
Remove end clean the oil filter screen.
Install the oil filter screen, right raankcase gasket
and GOver, kick starter pedal, muffler and footpegs(
side stand assembly.
Fill the crankcase with the »ecommended engine oil.
Start the engitifi.and let it idle for 2-3 minutes.
Stop the engine and check the oil level with the
moto'cycio upright
Hike ^Ure thai tlwre a»e i*> oil leaks
FILTER SCREEN
CENTRIFUGAL OIL FILTER CLEANING
Drain tho engine oil (page 2-2).
Remove the right crankcase cover (page 2-21. Remove the clutch lever, cam and outer covei
CLUTCH OUTER COVER
CLUTCH LEVER
CLUTCH CAM
Cloan the clutch outer cover and inside of the clutch outer ming a clean llnt-fiee doth.
NOTE ____________
Do not allow timt and din to enter the crankshaft oil passage. Do not use com prettied air.
Install the clutch outer covet, cam and lever. Install tho right crankcase cover, kick starter pedal. muffler and foot pegs/side stand assembly. Fill the cronkcase with tho recommended engine oil 12-2L
CLUTCH OUTER
Dalout litue: May, 11 ©HONDA MOTOR CO.. LTD-
15
2-3
LUBRICATION
HONDA
C70
OIL PUMP
REMOVAL
AIR CLEANFH COVFR
FRONT COVER
NUN
The oil pump can be removed v/th ihe engine mounlwl In lhn framo.____________
Remove the oil drain pluo !»nd drain the oil horn iho engine Ipagn 2-21. Hcmovo the tig*" crenktaie covef iDsge 2-?). Remove the clutch assembly (pao* 8-2).
Re:iiove iho three oil pump screws end oil pump.
MUFFLER KICK STARTER FOOTPEGS-SIDE RIGHT CRANK- ... PEDAL STAND ASS'Y CASE COVER
INSPECTION
Remove the oil pump body cover.
OIL PUMP SCHFi'/S
PUMP BODY COVER
2-4
16
Dnlcol ts«ie: May, 1980 ©HONDA MOTOR CO.. LTD.
iLo^
N?^ o °«-^59' '
-
Measure the rotor and clearance SERVICE LIMIT: 0.12 mm (0.005 in|
GASKET
DsteoHi&uc: May, I! ©HONDA MOTOR CO.. LTD.
17
2-5
LUBRICATION
C70
DISASSEMBLY
Remove the drive shaft.
Hetnovn iho inner and outer rotore
ASSEMBLY
Install th LUBRICATION POINTS
Use general purpose
when not --pitiflyd here.
Acply oil of grease to the other sliding uiitaa* not shown here.
CONTROL CABLE LUBRICATION
Periodically, diiconncct the thfoitfe. from brake and choke cable* at their oppef en*. Thoroughly lubricate The cablea and Inolr pivot point* with a commercially available cable lubficam.
Tl
ADVANCER CAM OIL FELT
THROTTLE GRIP
SWING ARM PIVOT BUSHINGS
SPEEDOMETER CABLE
LUBRICANT 1 DRIVE CHAIN
(RAKE CAM
CONE RACES -7 BALL RACES STEEL BALLS
AKE CAM
BRAKE PEDAL PIVOT
SPEEDOMETER BEAR
ENGINE
OaliMif Iswii: Mny. IS80 ©HONDA MOTOR CO., LTD.
13
2-7
C70
MEMO
20 Dale o< Issue May. 1980
©HONDA MOTOR CO., LTD
C70
3
INSPECTION AND . ADJUSTMENT
SERVICE INFORMATION 3-1
DRIVE CHAIN 3-11
FUEL LINES 3-3 BATTERY 3-13
THROTTLE OPERATION 3-3 8RAKE SHOE WEAR 3-13
CARBURETOR CHOKE 3-4 BRAKE SYSTEM 3-14
AIR CLEANER 3-4 BRAKE LIGHT SWITCH 3-15
CRANKCASE BREATHER (USAonly) 3-5 HEADLIGHT AIM 3-15
SPARK PLUG 3-6 CLUTCH 3-1S
VALVE CLEARANCE 3-6 SIDE STAND 3-16
CONTACT BREAKER POINTS 3-7 SUSPENSION 3-17
IGNITION TIMING 3-8 NUTS, BOLTS, FASTENERS 3-18
SPARK ADVANCER 3-9 WHEELS/SPOKES 3-18
CAM CHAIN TENSION 3-9 STEERING HEAD BEARING 3-18
CARBURETOR IDLE SPEED 3-10
CYLINDER COMPRESSION 3-10
SERVICE INFORMATION
GENERAL INSTRUCTIONS
• Engine oil
• Engine oil filler icreen
See page 2-2 See page 2-2
r*
TOOLS Common Valve Adjuii Ing wrench, 8*9 mm
Valve adjuiwr 8
Spoke nipple spanner B, 4.6 x 5.1 mm
SPECIFICATIONS
< Engine > Throttle grip liee play Spark plug:
077080030100 or commercially available 8x0 mm offset box end
wench 07708-0030400 07701 -0020200
2-6 mm (1/8-1/4 in|
He com mended ipar« plug I ] Canadian type
For cold climate (Below 5aC,irFI 5tandufd For extended high speed riiiing
ND NGK ND NGK ND NGK
U20FS IU20FSR-L) C6H [CR6HS1 U22FS IU22FSR-LJ C7HS ICR7HSJ U24FB IU24FSR-LI C9H ICR8HS1
Valv ek-jnifico:
Plug gap
Cold (Below 36X95^)
Inlake/Exhauit
0.6 - 0.7 mm (0.024 - 0.0?8 in) 0,05 mm (0.002 in|
Dateoflsjue: May, I960 ©HONDA MOTOR CO., LTD.
21
3-1
INSPECTION AND ADJUSTMENT
C70
Contact binnfcnr point gap: Ignition timing:
Initial. "F" mark
Advance dart
Full advonoa Idlo speed: Cylinder compression:
< Chassis >
Drive chain slack:
Front tvake lever free play:
Rea< brake pedal free play;
Tire;
0.3 - 0.4 mm (0.012 - 0.018 in)
IB'BTDC
1.875 .p."
30°8TDCat2,!J0Orpm
1,500 ± 100 rpm
12,510.5 kB/cm' (178;7psi)
15 - 25 mm (5/8 - 1 in) 20 30 mm (3/4- 1 1/4 in) 20-30 mm (3/4-11/4 In)
Front Hear
Tire sue 2.25-17-4PR 2.50-17-BPR
Cold lire pressure kg/cm' (psi) Up to vehicle capacity toad (135 kg, 300 lb] 2.0 (28) 2.8 (40)
Up lo 90 kg (200 lb) load 2.0128) 2.0(28)
TORQUE VALUES
Rear axle sleeve nut: Roar flx!e nut;
4.0-5.0kg-m<2B-361Mb> 4.0 - 5.0 kfl-m (29 - 36 ft-fb)
3-2
??
Date of Issue M8V. 1980 ©HONDA MOTOR CO., LTD
C70
INSPECTION AND ADJUSTMENT
FUEL LINES
Check Hie fuel lines for deterioration. damage or leakage. Replace it necei;arv
FUEL LINES
THROTTLE OPERATION
Chuck lot smooth throule grip full opening and pjr automatic lull closing In ill steering positions. Chflck the throttle cable and replace it i< it it ^
dotorlnrated, kinked or damaged
Lubricate the throttle table (page 21) it throttle operation is not smooth.
Measure throttle fffip '"Be ofay at the throttle grip flange.
2-6 mm (1/8-1/4 In)
FREE PLAY: 2-6 mm (1/8-f/d inl
' •>'
'"
Adjustment can be mode at either end of (he throttle cable,
Minor adjustment* are made with the upper 3d-|uiter.
Adjust by loosening th*; lock nut and turning the adjuster. Tighten the lock nut.
Major adjustments are made at mn lower adjuster on the carburetor after removing the front cover.
Remove the carburetor luhbei cap.
Turn the adjusni to obtain the specified free play-
Reeheck the Throttle operation.
LOCK NUT
RUBBEtl CAP
DECREASE PLAY
ADJUSTER
Date of Issue: May, ll ©HONDA MOTOR CO. LTO.
23
ADJUSTER
3-3
INSPECTION AND ADJUSTMENT
C70
y
CARBURETOR CHOKE
Cneck *or smooth choKo knob operating Mellon, The choke knob must move imooihly and stay whore positioned.
Adjust OV turning die Iriction adjuster "ul under the rubtw cop.
Pull the choke knob all the way oui aPd make Sore the choke valve Is doted by moving the carburetor choke lever.
Adjuslmenl:
Remove the front cover (page 5-2}.
Loosen Ihe cable damn and poll inn cuote casing up fuH to the choke valve it fully doted. PuKh ihe choke knob in and be sure the choke naive it fully open OV checking for 1~2mm (1/16-1/8 in) cable itnck.
Install the front cover.
AIR CLEANER
Re mow the air cleaner cover cap nut and cover. Remove ihe air cleaner element nut and element.
RUDGFR CAP CHOKE KNOH
CABLE CLAMP
ADJUSTER
ELEMENT
CHOKE LEVER
AIR CLEANER COVER
CAP NUT
Cloan Hie element by tapping ll lightly to looien dust. Blow avray ihe remaining dusi pV applying compretftitd air from inside the element
Replace the element i' it it excessively dirty, 'orn or damaged.
Install the element and air deaner cover:.
ELEMENT
3-4
24
Date of Issue: May, I98U &HONDA MOTOR CO., LTD-
C70
CRANKCASE BREATHER (USA only)
Remove the plug horn Ihc drain tube to drain deposits.
Iniinll the drain plug.
MOTE
Service more frequently when ridden In rain oi at full thtottla, c* il the doposi' level ran be MOT In ihfl drain tufaa transperam aectlon,
INSPECTION AND ADJUSTMENT
CRANKCASE BREATHER -"'DRAIN TUBE ^—-------. L_ j
f i^^(H^C^
/ t
/ / * \ »y
DRAIN PLUG
^
SPARK PLUG
Cloan any dirt Irom "round Ihe spark plug bate.
Disconnect the tpark plug cap.
Remove and discard tho ipork plug.
Memure the new spark plug oap using a wire-type feeler gauge.
SPARK PLUG GAP: 0.6-0.7 mm (D.O24-O.028 in)
Adjust by bending the tide electrode carefully.
With the plug washer attached, ihteod the new spark plug in by hand to prevent crossthreading.
Tighten the sperk plug another 1/2 turn with a mark plug wrench to compress the plug washer,
Connect the spark ptug cip.
RECOMMENDED SPARK PLUG:
0.6-07 mm -!_
(0.024-0.028 ml |"
Standard
For cold climate (Below 5"C.4i. "Ft
For extended high (penl riding
I Canadian type
NGK C7HS (CR7HS) NDU22FS (U22FSR-LI
NGK C6H Nu U20FS
(CRGH)
"T"MAHK
LOCK NUT
Check the valve cleaiancej by inwrttng a teelei guune between We adjusting iciew end valve item
VALVE CLEARANCES
INTAKE; 0.06 mm (0.002 In)
EXHAUST: 0.05 mm (0.002 in)
^t»
FEELEfl GAUGE ADJUSTING SCREW
Adjust by loosening the lock nut and turning ihe adjusting sciew until there is a slight drag on tne teeler gauge.
Hold the adjusting screw and tighten tho lock mil.
Rccheck the valve clearance,
Install the contact breaker point cover and valve irapectinn cops.
VALVE ADJUSTING WRENCH. 8 k 9mm r i «
VALVE ADJUSTER B
3-6
Date of l«je. May, II ©HONDA MOTOR CO. LTD.
C70
CONTACT BREAKER POINTS
Rcmovo thit contact biRJiker point cave'.
Clean the breaker point surfaces with an electrical contact clnnnof m remove any oil film or riiri.
INSPECTION AND ADJUSTMENT
BRrAKCR POINTS
tl the contact lurfacM are level bul grayish in color c ace tlighltv pined, tile th«m lightly.
If the points have a noticeable transfer of metal from one cut-fad to the other, have evidence ol heavy arcing, or aw worn at an angle, the point set should be replaced.
File lightly
USED l0 ,Bmove Dining and corroiion
UNSERVICEABLE - REPLACE If worn at an angle or bad'y pitted.
QCKING SCREWS
Rotate the crankshaft counierclocfcwiic, and make sure Uiat maximum point gap Is 0.3-0.4 mm I0.012-O.O16 ln| with a leeler gauge.
If the point gap Is incorrect, loosen the coniaci Ixeaker plaoj locking screws and adjuit the point pap.
Tighten the locking icrswc and rncheck the point
Install the contact breaker point cover.
Date ol Issue. May, 1980 ©HONDA MOTOR CO.. LTD.
27
3-7
INSPECTION AND ADJUSTMENT
IGNITION TIMING
NOTE
Ad|u&i the contact breaker point art engine ground,
Rotating the base plate counterclockwise will retard the ignition timing.
The tiring Is correct if the light goei out when both marks alipn_
ADJUSTMENT
Adjust by loosening the two contact breaker base plate screws and rotating the plate.
Rotating the bate plate clockwise will sdvanoe tfie ignition timing.
Rotating the base plate counterclockwise will rata/d the ignition timing.
Tighten the bass plate screw and nrchock the ignition timing and point gap.
Disconnecl the light and bat Wry,
Connect the BkAV breaker terminal wire,
iminll the contact breaker point cover,
C70
GROUND
CONTINUITY LIGHT
/
lAl BREAKER TEFIMINAI.WIRE
INDEX MARK
"F" MARK
BASE PLATE
""•
BASE PLATC SCREWS
3-8
2*
Dawof Issue; May, 1980
S HONDA MOTOR CO.. LTD.
'-
rs
C70
DYNAMIC METHOD (WITH A TIMING LIGHT!
NOTE
Adjust me contact breaker point gap beline making ihli edjuitrrient.______________
Remove the contact breaker point cov*t.
Connect a tachometer and timing light.
Start the esiBine and let it idle 2-3 minutes. Ad|uit the idlo speea if necessary.
IDLE SPEED: 1.500± lOOipm
Aim the riming light at the timing mark.
Tha timing ™ eoireei || the "F" mark align) with
mo in*k mark.
Adjust at described lor thtr italic method, " necev M'V.
Injiail the contact point cover
SPARK ADVANCER
Remove the contact point covar. Connect a liming light and tachometer, Stan the engine.
Bung engine spaed to 3.100 rpm and check thai 'hti index mark Is Between the lull advance maikt
Replace ihe advancst assembly II 1 *» not functioning pro parly.
Imtall iho contact b-cak« point cover.
INSPECTION AND ADJUSTMENT
TIMING LIGHT
INDEX MARK
ADVANCE MARKS
CAM CHAIN TENSION
Start the engine and lot it Idle.
Loosen tho cam chain teiuioner lock nut end lock bolt.
Thn tensioner will automatically position it«H to prov»do tho cm red utnsion.
II the chain n still noisy removB the lemioner plug. Gradually screw in ihc l«t*ioner adjusting screw until Ihn cam chain ft no longer noi*y. Imtall the. ransionor plug-
Tightan the tension"* lock fc©u and nut,
ADJUSTING SCREW
LOCK BOLT
"Ml ft
TENS10NER PLUG
LOCK NUT
of Issue: May, 1080 HONDA MOTOR CO.. LTD.
29
3-9
INSPECTION AND ADJUSTMENT
HONDA./
C70
CARBURETOR IDLE SPEED
NOTE ^_^_
' ItMpeei und ndlusi carburetor idW fpeed afie'
all oihc engine arl)u;;imcnti are within kid
cifi cation. - Trie -nyinc must be warn lor accurate idle
inspection and atlJusimBnt Ten minutes ot
stop ami go riding «t sufficient,
Connect a tachomoler.
Warm tip (he engine, 'Hill mo wanwniijion to NEUTRAL, and hold tht motorcycle uptight
Inspect and ad|usl fetta speed with th* throttle nop screw. if necessary.
IDLE SPEED: 1.500 : 100 ipm
CYLINDER COMPRESSION
Warm up the engine.
Stop thu engine un'l iwmovo the tpai* plug.
I met the compression qsug#.
Pudi the choke kn>>b in.
Open the throttle grip lully.
Crank the engine with the nonet motor.
NOTE
Crank tr» engine until thn gauge reading stop* rhino. The maximum reading it usually leachtxi within 4-7 seconds.
COMPRESSION PRESSURE: 12.5 ¦ 0:6 kg/cm3
1178: ? pw<
Low compression can be cauied by:
Improper value adjustment
Valve leakage ¦ Blown cylinder head yavket
Worn piston ring or cylinder
High compression o»n bo caused by:
Carbon deports i" comhutiiiin cnombor or on the piston crovfV
THROTTLE STOP SCREW
COMPRESSION QAUGE
ft*
3-10
Date of issue: May, 1380
Q HONDA MOTOR CO.. LTD.
-
HONDA.
C70
DRIVE CHAIN
INSPECTION
dare the vehicle on its side stand and shift the
transmission Into neutral.
Turn the ignition switch OFF.
Remove the drive chain Inspection hole cap.
Move the drive chain up and down by hand and measure the amount of stack.
SLACK: 15-25 mm (6/8-1 In] Adjust il -*eoatsatv.
INSPECTION AND ADJUSTMENT
ADJUSTMENT
Remove the rear axle MM cotter pm and loosen the hiIq and sleeve nuts.
Turn tho adjusting nun on both udes an equal number of turn* to obtain ihe specified chain slack.
CAUTION:
fie siur thai the Otdex mark on ihe chain aclfusier aagrtr wifft Ihe tame grgduaiUm on both sulci of Ihe twingur'n.
Tighten the sleeve and axle nun and in«all a new cotter pin.
TORQUE:
SLEEVE NUT: 4.0 - 6.0 kg-m 129 - 36 ft-lb)
AXLE NUT: 4.0 - 6.0 kg-m 129 - 36 tt-lbl
Tighten the *d|us!ing nuts.
Recheck drive chain llack and Ireo wheel rotation.
Cneck b'ako pedal Inns play and ad|ust If necessary. Lubricate the drive chain with a comrrwercioHy available drlvr chain lubricant through the inipec-jfOfl hole.
CLEANING
When tlii; drive chain becomes extremely dirty. It should bo removed and cleaned prior to lubrication
A3 follOWl:
Remove the frame leftside cover.
Remove the drive sprocket cover.
Remove «* two lower chain easn botti and lower
chain cast).
Remove the upper chain case.
Remove the axle nut colter pin end loosen the axle
nut. sleeve nut and adjusting nut*.
COTTER PIN
X
AXLE NUT ADJUSTING NUT
LEFT SIDE COVER SLEEVE NUT AXLE NUT
DRIVE SPROCKET COVER
LOWEH COTTER PIN
CHAIN CASE
' issue: May. 1980 HONDA MOTOR CO., LTD.
31
3-11
INSPECTION AND ADJUSTMENT
Remove the matter link relatninrr clip and mes'is
link.
Remove iIki drivo chain.
©Ban the driwr chain in nonflammable or h&rt Hash poinl sorvnnt with a brush «>d allow it to dry-Inspect Wis urivo chain tor wear or damage. Replace any chain that d nccjs«vely vAwn or damaged.
OflVE CHAIN MASTER LINK
RETAINING CLIP
inspect III" drive- and driven sprocket tooth for excessive wear or damage.
Replace if necessary. NOTE
Nivnt Install a new drive chain on worn sprockets or a worn chain on now sprockets. Both chain and sprockets must be In good condition, or the replacement chain or sprockets will wear rapidly.
DAM AG F
WE AH
NORMAL
Lubricate the drivo chain. NOTE
Commercial aerosol type drive chain lubricant is lecommtinded.
I'Htall ihe drivo chain. NOTE
Now the direction of the master link retaining ofip.
Install the upper and Inwor chain cases, driv;e Sprocket cover and luft side cover.
Adjust drivfl chain black |pnge 3-111.
Check brake pedal free play and adjust, II necessary.
DIRECTION OF ROTATION
MASTER LINK
CHAIN RETAINING CLIP
3-12
32
Date of Issue; May. 1980 ©HONDA MOTOR (XJ.. LTD.
"
C70
INSPECTION AND ADJUSTMENT
BATTERY
GROUND CABLE
POSITIVE CABLE
Remove the right tide cover.
Disconnect the ground cabto at the frame.
Disconnect tho positive cable at the battery terminal.
Remove the battery holder plate.
Remove the battery.
Inspect Mm bottery fluid level.
When the fluid level neais Uw lowrr level, refill with distilled w*tet to the upper level.
NOTE
Add only distilled water. Tap water wil shorten the service life of tho battery.
» WARNING
The haiieiv eleitrnlyte conratm uilfurtc acid. Protect your eyes, skin, and clothing. In case of eoaiarl. flush thoroughly with water and contact a doctor if electrolyte ten in you/ yt
BATTERY
FILLER CAPS
HOLDER PLATE
Replace the battery, if sullation forms or sediments accumulate on the bottom.
UPPER LEVEL
BRAKE SHOE WEAR
Replace the broke shoe* II the arrow on the indicator platg aligns with the "." mark on the brake pan#l when iho brake \% applied.
¦fi"MARK
AHROV.1
ARROW
MARK
Date of Issue; May, 1980 ©HONDA MOTOR CO.. LTD.
3-13
INSPECTION AND ADJUSTMENT
C70
BRAKE SYSTEM
FRONT BRAKE LEVER FREE PLAY
Muaiura the Ironi brake lewer fit* play bi Hie lip ot the brake levor.
FREE PLAV: 20-30 mm (3/4-1 V^lnl
+4*m
I! adjustment is necessary, turn the adjusting nut until the concct Ires play is obtained.
NOTE
Make wie the cut-out on ttic adjusting nut is wated on tho brake arm pin o'tiw making linol free play fld Just man t.
REAR BRAKE PEDAL FREE PLAY
Check trui hraku pedal nee play.
FREE PLAY: 20-30 mm (3/4-1 1/4 in)
ADJUSTING NUT
3-14
34
Date of Issue: May, 1980 ©HONDA MOTOR CO., LTD.
C70
INSPECTION AND ADJUSTMENT
K adjustment Is necessary, lurn the adjusting nut until thacorrnct free play is obtained
NOTE
Make aire the cuiuui un Ihe adjusting nui Is watec on the brake arm pin after making th« final free play adjustment.
BRAKE LINKAGE
Check the brake cable, brake rml. biake pedal and brake lever for loose connections. excessive play, or damage.
Replace k repair if necasiarv.
AOJUSTING NUT
BRAKE LIGHT SWITCH
NOTE
Perform this adjustment after adjusting brake podal free play
Adjust tSe rxrake light switch so that the brake light will tigh; when tha brake pedal Is depressed and the brake begins engagement.
NOTE
• Do not turn the switch body.
• The Iront brake light switch does not requite
adjuilmeot.____________________________
Adfutt by turning the switch adjusting nut.
SRAK.E LIGHT SWITCH
ADJUSTING NUT
HEADLIGHT AIM
r
Ad|ust vertically by turning tho wirdcal adjusting
screw.
Turn Ue adjusting screw clockwise to direct the
beam ue,
Adjust horirnrititlly by turning the horizontal adjusting srrew
Turn the adjusiing screw clockwise to direct the beam lonaid the left side ol the rider.
NOTE
At.iji.-t the headlight beam as specified by local laws and regulations.
ft WARNING
I'.'
HORIZONTAL ADJUSTING SCREW
.in in/mi/wHy adjusted headlight may Mind oncoming drivers, or it may fail to light the road 'or a safe distance-
VERTICAL ADJUSTING SCREW
Data af Issue: May. 1980 ©HONDA MOTOR CO.. LTD.
3-15
INSPECTION AND ADJUSTMENT
C70
CLUTCH
Stop the engine.
Loosen tho adjunct lock nut and turn the dutch adjuster clockwise one turn;do not tutu itxcesslvuly.
Slowly lurn ihc adjuster counterclockwise and stop when resistance Is fell.
From this point, turn the adjuster clockwise 1/8 to 1/4 turn, and tlghien the lock mil,
Chock to see that the clutch is not slipping and is properly disengaging.
LOCH NUT
ADJUSTER
SIDE STAND
Check the rubber pad for deterioration or wear.
Replace if any wca' exceeds to the wear line shown.
NOTE
When lepiacing. use a rubber pad with Ihe mark "BELOW259 lb*ONLY",
Check the side stand spring toi damage and loss of tension, and the skJo stand assembly 'or freedom of movement and bending,
NOTE
Spring tension is corrccl if the measurements
fall within 1.6-2.6 kg 13.3-5.5 lh) when pulling the side stand lower end with a spring scale.
")
SPRING SCALE
3-16
36
Deteof laue: May, 1980 ©HONDA MOTOR CO., LTD,
"
C70
INSPECTION AND ADJUSTMENT
SUSPENSION
* WAGING
On not rliie a vehicle with faulty suspension. Loose, worn or ilturtaacJ suspension parts lmi>atr vehicle stability and control.
FRONT
Qieck the action of the front forks.
Replace >jamaoc«l components which can no) be
Tighten all nuts and bolts
Lubricate the suspension arm pivots.
/
GREASE FITTINGS
REAR
Place the motorcycle on a support to raise the feat wheel oH the ground.
Mow rt» roar wheel sideways with force to see it the swigarm bushings are worn. Rrplaco i| excessively WO«n.
Check the shock absorbers for leaks or damaga.
Tigfiten aj| rear suspension nut* and botls.
Datcotlmie: May, 1980 ©HONDA MOTOR CO., LTO.
37
3-17
INSPECTION AND ADJUSTMENT
C70
NUTS, BOLTS, FASTENERS
Check thai all chassis nuts and bolt* an lightened to correct torque values.
Check all cutlet pins and safety clips.
WHEELS/SPOKES
NOTE
Tire pressure should be checked when tire*am COLD,
RECOMMENDED TIRE PRESSURE AND TIRE SIZE:
1 roi- Reai
Tire si/o 2-2*17-4PR 2.50-17-6PR
Cold lire pressure kg.W Up to vehirio capacity Load (135 kg. 300 Ibl 2.0 (28) 2.8 140)
Up to 90 kg <20D lb) load 2.0 {281 2.0 (28)
Check tho tires for cuts. Imbedded nails, ot other sharp objects.
Check Hie from and rear wheels lot iruenett..
Measure the feed depth at the center ot the tire*.
Replace the tirot » Iho weed depth reachoi the frjllowing limit,
MINIMUM TREAD DEPTH: FRONT: 1,5 mm ' I ,'16 In) REAR: 2.0 mm (3/32 In)
GAUGE
SPOKE NIPPLE SPANNER 8,4.5x5.1 mm
Rellghtrm ihe whiMrl ipokos periodically.
STEERING HEAD BEARIN6S
NOTE
Chock that the control cablet i with handlitbar rotation.
not interfere
Raise the front wheel o" the pound.
Cheek that the handlebar rotates Ireely.
If (he handlebar mpves unevenly. binds, or has vertical movement, adjust the iieeting head hearings by Turning ihn steering head adjusting nut (oaoe 12-181.
-- «
~
HEAD BEARINGS
3-18
38
Dateof Issue; May. 1980
Q HONDA MOTOR CO., LTD.
C70
MEMO
mr of \nue: May. 1960 HONDA MOTOR OQ.. LTD.
FUEL SYSTEM
C70
4-0
40
Datncrf Isnnt: Mnv, 1980 ©HONDA MOTOR CO.. LTD.
C70
4. FUEL SYSTEM
r\
r*
SERVICE INFORMATION 4-1 THROTTLE VALVE ASSEMBLY 4-5
TROUBLESHOOTING 4-1 CARBURETOR INSTALLATION 4-6
CARBURETOR REMOVAL 4-2 FUEL STRAINER 4-6
THROTTLE VALVE DISASSEMBLY 4-2 PILOT SCREW 4-7
FLOAT AND JETS 4-3 HIGH ALTITUDE ADJUSTMENT 4-8
CARBURETOR ASSEMBLY 4-4 FUEL TANK 4-9
FLOAT LEVEL 4-5
SERVICE INFORMATION
GENERAL INSTRUCTIONS
• Usecautioowhenworkino with ga»line. Always work Inawellventiiaiod area and away fromipfliksor openfl
• When dlBswmhling luol *v«em Oorts. noiu the location* of the O-rlngs. Replace them with naw one* on reassembly
• l he ttoat Bowl has a drain plug that con ofl loosened to drain residual gasoline.
TOOL Common
F loat gauge SPECIFICATIONS
07401 0010000
1980 1981
Veniuri dia, 14 mm 10.55 inl
Identification No. P832A PB32C
Float level 10.7 mm (0.42 inl ¦•-------------------
Mi in ffli s w tm
Slaw jet - 35
Thiot tie valve #Z5 ¦
Jet needle 72A 72C
Throttle grip free play ?-6mm(l/B- 1/4 Inl
Pilot screw initial opening See page 4-7
TROUBLESHOOTING
r. r-.ij hi- i- .!¦ ¦ - but won't ttan Rough Idle Lean mixture
1. No lurl in tank 1. Ignition malfunction 1. Clogged fuel ten
2. No fuel to carburetor 2. Idle speed incorrect Z Faulty float valve
3. Engine flooded with fuel 3. Carburetor malfunction 3. Float level low
4. No spark at plug 4. Fuel contamlnaled 4. Fuel cap venl Mocked
(ignition malfunction) 5, Air cleaner clogged 6. Intake air teak Misfiring during acceleration 1. Ignition malfunction Backfiring 5, Fuel strainer screen clogged 8. Restricted fuel line 7. Intake air leak
7. Improper choke operation 8. Air vent tuhu clogged
8. Improper throttle operation 1. Ignition malfunction 2- Carbunitor malfunction Rich mixture
Hard ftarting or stalling after itarting 1. Clogged air Jets
1. Improper choke operation Poor performance (druealitliiy) 2. Faulty float valve
2. 1 yni I d disconnect the choke cable.
Loosen the air cleaner connecting tube band. Remove die bote securing the carburetor to the intake pipe
Unscrew the carburetor lop and pud tho throttle valve out.
Remove the carburetor mounting bolts and ear-burovK-
CAPBURETOR TOP
BOLTS
CHOKE CABLE
DRAIN SCRF.W
THROTTLE VALVE DISASSEMBLY
Remove th« carburetor top end throttle valve,
THROTTLE VALVE
THROTTLE VALVE SPRING
Compress the throttle valve spring and remove the throttlo cable *rom the throttle valve groove.
CABLE END
4-2
42
Dateot Issue: May. I960
© HONDA MOTOR CO.. LTD.
-y
C70
FUEL SYSTEM
Remove iho naedlis clip 'ot,iifwr-Remove tlw jet needle and dip,
(mpeci the rluoitlf valve and JpI needfe lor dirt, icmwhcs ot wear,
THROTTLE VALVE
NEEDLE CUP
^ *
*f
?
/
/
JET NEEDLE NEEDLE CUP RETAINER
FLOAT AND JETS
Remove the float thamber and pull out the float pin. Removo the float and ftoa: valve.
©fit pact the lloat valvo and icat for n>oov», nicks or deposits.
FLOAT FLOAT PIN
I
FLOAT VALVE
Inspect the lloat valve operation.
<
FLOAT VALVE
FLOAT
OateoflSRie: May. 1980 ©HONDA MOTOR CO,, LTD.
S3
4-3
FUEL SYSTEM
HOWDA
C70
Remove the main jet, needle jet holdirr and needle jet.
NOTE
NEEDLE JET HOLDER MAIN JET SLOW JET
The slow eii (el cannoi be removed. It is a
PUSS fit.
Blow all |cl* and body parages with compressed air-
CARBURETOR ASSEMBLY
Install the needle let. needle jot holder and main Install the float and lioat valve together.
NOTE
Take care not to damage the jett whan installing,
FLOAT
NEEDLE JET HOLDER
MAIN JET
FLOAT VALVE
FLOAT PIN
*
4-4
44
Daieoflsfcje May, 1H80 ©HONDA MOTOR CO., LTD.
~
C70
FUEL SYSTEM
FLOAT LEVEL
Romovo the float chamber.
Measure me float level with me flout tip just contacting the float «alve.
FLOAT LEVEL: 10.7 mm (0.42 In)
Replace tho final. if the float level Is not within
specification.
FLOAT LEVEL GAUGE 074O1 0010000
LOAT LEVEL ,7mm 10.42 in|
n*
THROTTLE VALVE ASSEMBLY
Install (he dip on the jet needle.
Install tho lot rwcdlo kuo the throttle valve ami demo it with tho naedle clip rotator*.
NOTE
Install the noodle clip retainer 10 it put) on Ihe throttle valve bottom.
NEEDLE CLIP RETAINER
Compresi the throttle valve spring and install the cable inlo the valve.
THROTTLE VALVE SPRING.
CABLE END
Date of issue: May, 1! ©HONDA MOTOR CO.. LTD.
4-5
FUEL SYSTEM
C70
Iris) all ihu llvoillu valve with (hi! ituotlle valve groove aligned with die throttle stop screw.
THROTTLE VALVE CHOOVE
THROTTLE STOP SCREW
CARBURETOR INSTALLATION
The installation sequence is essentially the reverse of removal.
¦J r;n
•When installing the throttle valve, align the throttle valve groove with the throttle stop screw.
• Clamp the choke cable end on tho cable clamp,
Perform the following Inspections and adjustments.
* Throttle operation (page 3-3) ¦ Carburetor choke (page 3-4)
• Carburetor idle speed (page 3 101
CHOKE CABLE CLAMP
O-RING FUEL STRAINER
FUEL STRAINER
Turn the fuel valve OFF.
Drain the carburetor by loosening Ihe rtreln screw.
Remove the fuel valve, O-ting and strainer.
Clean tho strainer.
Install Ihn Strainer, O-ring and luel valve.
FUEL VALVE
4-6
A6
Date of Issue: May. 1980
1)HONDA MOTOR CO.. LTD,
C70
FUEL SYSTEM
PILOT SCREW
REMOVAL/INSTALLATION NOTE
The pilol screw is factory pre-set and should not bo removed unless the carburetor Is overhauled.
Remove ine carliuretor.
Remove the float chamber.
Turn the pilot screw in and carefully count the
number of turn* before It wats lightly.
Make a noltt of this to use ai n reference when
installing the pilot screw.
CAUTION:
Damage to the pilot screw and seat will occur If the pilot screw is tightened asainsi the seat.
Remove the pilot screw with ino limiler cap attached. CAUTION:
Any forcible attempt to remove the ptlot icrew llmlter cap will break Ike screw.
Inspect the pilot screw fo> wear and replace ||
necessary.
Install the pilot straw and return it to lu original
position as noted during removal.
Perform pilot screw adjustment if a new pilot screw
Is installed.
NOTE
Do not install a llmlrnr cap on a now pilot screw until after adjustment has been made {tee below).
ADJUSTMENT
NOTE _____________________
The pilot screw ii factory pre-ict and no edjustmtnt is necessary unless the pilot screw is replaced.
j
Turn Ihe pilot screw clockwise until it seats lightly
and back il out lo Ihe specification given. This Is «n
Initial setting prior to the final pilot screw adjuvt-
mem.
INITIAL OPENING: 1980 - 2 turns out
1381 -2 t/2 turns out
CAUTION:
Itaniarc to Ihe t'Hol screw and seal will occur if lite pilot screw is tightened against the seat,
Warm the engine up to operating tumpeiature. Stop and go riding for ID minutes is sufficient. Connect a tachometer. Adjust the idle speed with the throttle stop screw.
IDLE SPEED: 1,500 ' 100
Romow tho Screw and Boll wcurlng ihc fuel tank. tin.-ii remove the luel lank.
Install the 'uel tank in We revorte c*rjer o* removal.
Moke *urn thorn arc no fuel leaki.
Oeck the vent nolii of tho filter c«p lor blockage.
SCREW
Date of Issue: May. 1980 ©HONDA MOTOR CO.. LTD.
4-9
ENGINE REMOVAL/INSTALLATION
C70
2.5-3,5 teg-m (18-25 fMbl
5-0
50
Datsof Inuc Muv. i960 ©HONDA MOTOR CO., LTD.
r^
C70
5
ENGINE REMOVAL/ INSTALLATION
SERVICE INFORMATION ENGINE REMOVAL ENGINE INSTALLATION
5-1 5-2 5-4
r
SERVICE INFORMATION
GENERAL INSTRUCTION
The following parti o» components cwi be serviced wuh Uie engine installed in the Irnme.
• Clutch
• Geafshilt linkage
• Oil pump
• Cylinder head
• Cylinder
• Piston
• A.C.goneratw
• Starter motor
Carburetor
SPECIFICATIONS
Engine d'y weight Oil capacity
IB kg (39.7 lb)
0.7 lit (0.74 US ui, 0,62 Imp qt) at engine asiemUy
0.8 (it (0.65 US qt. 0.53 Imp qtl at change
TORQUE VALUES
Engine honoei boln Fcwtpegs&ide stand *a'v
2.6-3.Bkg-m(lB-25ft-IW 2.0-Z5kgm|14- 18 Mlb)
Dateol Issue: May. 1S80 ©HONDA MOTOR CC. LTD.
5t
5-1
ENGINE REMOVAL/INSTALLATION
C70
ENGINE REMOVAL
AIR CIF.ANER COVER
Dirtln tho ringing oil,
Remove the air cleaner cover b»kI front rawer band.
Rnmove tho front cover.
'RONT COVER BAND
FRONT COVtFt
STARTER CABi-F
Looion the exhaust pipe lotting nuts
Remove the mutficr mounting nuU and remove the muffler iiu«rnfah/.
Disconnect the mrlei cable.
MOUNTING NUTS
SETTING NUTS
Support the motorcycle upright wit" a "and Remote tha footpooi/iido stand aiiembly. Unhook the brake pedal return spring from ihc engine hanger hull.
RETURN SPRING
FOOTPEGS/SIDE STAND ASSEMBLY
5-2
52
Dale of Iwue: May, 1980 ©HONDA MOTOR CO., LTD.
"
C70
ENGINE REMOVAL/INSTALLATION
Remove the high tension wire *'«m Ihe spat* p|ug
and cUmp.
Disconnect thn intake pipe Irom the engine.
NTAKE PIPE
HIGH TENSION WIRE
r
Ramovu ihe coilpr pin and loosen tho axle and slDffwe null.
Loosen ihe drive chain articling outs.
Remove ihe left aid* cover, engine sprocket cover
and iQvtet chain case.
AXLE NUT SLfcfcVE NUT
•a
LOWER CHAIN COTTER PIN ADJUSTING NUT CASE
WASTER ' INK RETAINING CLIP Remove Ihe master link teiainino clip >"¦<) master link ai tha drive sprocket
"~
Date of Issue- May. 1980 ©H(JNDA MOTOR CO.. LTD.
53
5-3
ENGINE REMOVAL/INSTALLATION
C70
Disconnect the A.C. generator couplet.
Remove the breathe* hose from the separator and clamp.
Remove the wo engine Hanger bolts end remove the engine.
A.C. GENERATOR BREATHER HOSE COUPLER
ENGINE HANGER BOLTS
ENGINE INSTALLATION
Install the engine In the reverse order of removal. NOTE _____
• When lnitatH"9 <>* d'i« chain master link, make lure thar the retaining clip open end feces tliB opposite direction ol normal chain
rotation. ¦ Route thewlrejand eablei properly (page 1-61-
• Fill iho crankcate to the proper level with the recommended oil Ipage 2-2).
• Adjust the drive chain tension loagc 3111.
TORQUE VALUES:
Footpegs/tide Hand aisnmbly: 2.0-2.5 kg-m (14-16 ft-lb)
Engine hangs' botu:
2.6 3.5 kg m (18-251Mb)
RETAINING CLIP
DIRECTION OF ROTATION
?.ft 3.5kg.m (18-25 ft-lb)
5-4
54
Date of Issue: Mav. 1980 ©HONDA MOTOR CO., LTD.
C70
MEMO
r
I*
r-
55
Date ot issue: May. 19M1
SHONDA MOTOR CO.. LTD
CYLINDER HEAD/VALVE
C70
0.9 - 1.2 kgm (7-SfMb)
0.5-0.9k9tit (4 - 7 ft-lbj
6-0
Dale oHssuo: May. 1980 ©HONDA MOTOR CO., LTD.
C70
6. CYLINDER HEAD/VALVE
SERVICE INFORMATION TROUBLESHOOTING CYLINDER HEAD REMOVAL CYLINDER HEAD DISASSEMBLY VALVE GUIDE REPLACEMENT 6-1 6-2 6-3 6-4 6-9 VALVE SEAT INSPECTION/ REFACING 6-10 CYLINDER HEAD ASSEMBLY 6-11 CYLINDER HEAD INSTALLATION 6-13
SERVICE INFORMATION
GENERAL INSTRUCTIONS
• This section covert maintenance and inspection of the cylinder head, valves, camshaft and rocker arms. Thcw services cen hit done with the engine in stalled.
• Camshaft and rocker arm lubricating oil is fed through oil passages, Bo tun? the- passages a-> arm shaft O.D. 9.978 - 9.989mm (0.3928 -0.3933 in) j 9.91 mm (0.390in)
Rocker wm 143. 10.000 - 10.016 mm (0.3937 - 0.3943 In) 10.10 mm 10.398 in)
Valvn spring Free length Inner 26.1mm (0.99 inj 23.9 mm 10.94 m,
Outer Inner 28.1 mm (1.11 in) 26.9 mn (1.06 ln|
Prsluad/lernjih 2.45 -2.75 kg/22 7 mm (6.401 -6.063 lbs/0.89 in) 2.3 kg/22.7 mm (5.07 lbs;0.89m)
Outer 6.65 - 7.75 kg/24,9 mm (14.661 - 17.086 lbs/OSS in) 6.3 kg/24.9 mm (1389 "* 0.98 ml
Valve guide/ Valve stem IN. 5.455 - 5.466 mm (0.2148-0.2162 in) 5.400 mm (0.2126 In)
vafvo O.D. tx 5.435-5.445 mm (0.2140-0.2144 in) 5.400mm (0.2126)n|
Valve guide Let IN. 5.475 5485mm (0.2156 - 0.2159m) 5.500 mm (0.2165 in I b.bOOmm (0.2166 in,
FX 5.476-5.486 mm (0.2156 - 0.2169 m)
Stem-to-guide clearance IN. 0.010 - 0.030 mm (0.0004 - 0.0012 in) 0.08 mm (0.003 in)
EX. 0.030 0.050 mm (0.0012 0.0020 in) 0.10 mm (0,004 Inl
Vafvo seat width 1.0 mm (0.04 Inl 1.1 Hiti. (0.06 in)
f . ¦ 1 ^^. ^^H ^. ^m ^^m ^. ^ ^J l k l k x ^k h k 0.05 mm (0.002 in)
Cylinder nead w nip-age
Date of Issue: May. 1980
I? HONDA MOTOR CO,. LTD.
57
6-1
CYLINDER HEAD/VALVE
C70
TROUBLESHOOTING
noise prublomi which
Pnrlormencri problems ralated to The cylinder head can usually be diagnosed by a compression ten, can be traced to the top end with a sounding rod or stethoscope.
Low Compression Compression too High
V Valves 1. Excessive carbon build-up on piston head or combustion
- Incorrect valve adjustment chamber
- Burned or bent valve. ExM(sive No(j6
- Inc-rect valve timing , Incorrect valve adjustment
Z Sticking vilvn or broker, valve spring
3. Dnmaged or worn camthalt
4. Loose or worn cam chain
5. Worn or damaged cam chain tensions)
6. Worn cam sprocket teeth
2. Cylinder head
— Leaking or damaged nead gasfcet
— Warped or Clacked cylinder head
3. Cylinder and piston (Hefcr to Suction 7)
6-2
58
Date of Issue: May, 1
©HONDA MOTOR CO., LTD.
¦
C70
CYLINDER HEAD/VALVE
CYLINDER HEAD REMOVAL
Remove the front cow
DticannKci the intake pipe Irom trw cylinder head.
Rcmovo Iho contact point covet and turn the crankshaft counterclockwise to align the "T" mark w«h ihc Index mark.
INDEX MARK
"T" MARK
Hemove ihc mulllei.
Remove the spmk plug cap.
Remove the cylinder head left side ccttr by removing the through bolt from the right side.
CYLINDER HEAD LEFT SIDE COVER
Remove the camshaft sprocket.
CAMSHAFT SPROCKET
Date of Issue: May, ©HONDA MOTOR CO.. ITD.
6-3
CYLINDER HEAD/VALVE
C70
Loosen the cylinder 6 mm bolt.
Remove the cylinder mail fi mm boll and cylinder head cover.
Remove the cylinder head.
CYLINDER HEAD COVER
CYLINDER HEAD 6mm BOLT
CYLINDER 6mm BOLT
DOWEL PINS
Remove the O-rings. cylinder head gasket anil dowel pins.
GASKET
O-RINGS
CYLINDER HEAD DISASSEMBLY
Hr.mme ihe cylinder head light ude cover and gasket.
Hmnwc iho valvo inipection caps and O-tingi.
VALVE INSPECTION CAPS
/ "I
CYLINDER HEAD RIGHT SIDE COVER
6-4
60
Daiual I spin: May. I! ©HONDA MOTOR CO., LTD.
C70
CYLINDER HEAD/VALVE
6mm BOLT
Screw on 8 mm bolr mio ihe u valve spring cot ten. letalnen. spring* and valves.
CAUTION;
7b prevent last of lemhn. do mil compress the valve iprings more than necessary' "¦ remove (lie cot/en_________________________
Remove valve spring scan, stem seal caps and itmi seels.
VALVE SPRING COMPRESSOR
Date of Issue: May, 1980 ©HONDA MOTOR CO., LTD.
61
6-5
CYLINDER HEAD/VALVE
C70
Remove carbon deposit* from (he combmiiun chamber.
Clean off the head gasket surface. NOTE
• Avoid damping trto goiket mrtnee.
• Gasker material villi come off easlei if toaked )n solvent.
ROCKER ARM INSPECTION
Impact he locker ernt for damage, wear or clogged oil hole*.
MeasU'e the I.O. of the rocker arm.
STANDARD: 10.000-10.016 mm 10.3937-0.3943 in)
SERVICE LIMIT: 10.10 mm 10.398 In)
^
ROCKER ARM SHAFT INSPECTION
Inspect the rocker arm shaft for wear or damage
Measure the O.D. of the locker arm shaft,
STANDARD: 9.878-9.989 mm
(0.3928-0.3933 in) SERVICE LIMIT; 9,91 r*m (0.3902 in)
6-6
6Z
Date of Usue: May, 1980
'£• HONDA MOTOR CO.. LTO.
C70
CYLINDER HEAD/VALVE
CAMSHAFT INSPECTION Using e micrometer, meamre me cam
<'.} ::i.V. t\ii rival m tlatiiaqi.
STANDARD: 28.07 mm (1.026 Inl SERVICE LIMIT. 25.69mm 11.011 inl
J
o
CAMSHAFT OIL CLEARANCE
Manure and record the lamshatt journal O.D. Measure and record th«cam*heft bearing I.D. in the Cylinder hood-Determine the camshaft bearing oil clearance.
STANDARD: 0.010-Q.026 mm
III.COO? 0.0010 ml SERVICE LIMIT: 0.05 mm (Q.OQZ ln|
VALVE SPRING FREE LENGTH INSPECTION
Measure Hie length of the springs
inner and outer valve
STANDARD:
Inner: 25.1 mm (0.99 In) Outer: 28.1 mm 11.11 in)
SERVICE LIMIT:
Inner: 23.9 mm 10.94 in} Outer: 26.9 mm (|,u6 mf
Date ol Issue; M»v. 1930 ©HONDA MOTOR CO.. LTD.
63
6-7
CYLINDER HEAD/VALVE
HONDA/^
C70
VALVE STEM-TO-GUIDE CLEARANCE
Imped each valve for ben>li"9. burning, scratches or
itbnormal stem wear.
Cheek valve movement EX: 0.10 mm 10.004 in)
VALVE GUIDE REAMER ( 079840980000
If the stenvto-guide clearance exceeds tho wrvke limits, determine if ¦ nnw guide will) standard dimensions would bring ttw clearance within tolerance. If so, replace the guides as necessary and team iu fit
If the stenvioguido clearance- exceeds the service limiti with new guides, replace the valve* and guides.
NOTE
Relace die valve seats whenever the valve guide* arc replaced lpag"i6T0l.
6-8
64
Dale ol Issue: May. 1980 ©HONDA MOTOR CO., LTD,
r
C70
CYLINDER HEAD.'VALVE
VALVE GUIDE REPLACEMENT
Support the cylinder bead and drive the guide out from the port side.
NOTE
When driving out the valve guide, do not damngo the head
r'
VALVE GUIDE HEMOVER
Install a new oversea vglvs guide from the rop of the head-
VALVE GUIDE DRIVER 079-12-1180(00
Ream the now valve guide after Imialialion. NOTE
Use cutting oil on iw reamer during thii opera lion. 1 Roteto ;ha reamer when inserting and (amoving
't. _
Ro*acn ihc vaive seat (page 6-10).
Clean the cvli"d« head thoroughly to remove any
metal particles.
VALVE GUIOE REAMEH 07984-0980000
DatPol l;tue May, 1!
© HONDA MOTOR CO,. LTD.
65
6-9
CYLINDER HEAD-VALVE
C70
VALVE SEAT INSPECTION/REFACING
Clean both ittukt! imd rohmist valves thoroughly to remove carbon deposit) Apply a light coating <>i valve lapping compound lu cwh valve face. Lap each valvo and scat using a rubber hose 01 other hand-lapping tool.
NOT:
Take care not to allow (hi* compound to enter between tho valve stom and guide. After lapping, wash out Die compound com pleiely and apply a coat of engine oil to the vulva (ace and seal.
Romove the vgfvo and inspect the face CAUTION:
The valves pinrn/i be ground. If the valve face Is fffugh, warn unevenly, or contacts, i/te seat improperly, the voire hum be replaced
Inspect ihe valve seat.
II the icat it too wide, too narrow, or has low spots, the seat must be ground.
NOTE
Follow the relecer manufacturer's operating instructions.
VALVE SEAT WIDTH
STANDARD; 1.0 mm (0.04 ml SERVICE LIMIT: 1.6 mm (0.06 in)
Alter cutting ihe seat apply lapping compound to the valve face, and lap the valve using light pressure. Atlw lapping, wash any residual compound off the cylinder head and valve.
6-10
66
Dote uf W**« May, M ©HONDA MOTOR-CO,, LTD.
r
C70
CYLINDER HEAQ'VALVE
CYLINDER HEAD ASSEMBLY
Install nek waive item seal*.
Lubricate each valve item with molybdenum disulfide g'l-iisi- and insert tho valve into the valve (Wide.
NOTE
VALVE INNER SPRING STEM
COTTER SPRING SEAT SEAL
To avoid damage to the stem wml. turn the I slowly when insetting.
Imull tho valve springs and retainers.
;._»**
dP
AO
SPRING OUTER RETAINER SPRING
STEM SEAL VALVE CAP
Install ihr valve cotter*. CAUTION:
7b prevent temkm lots, > not comprint the valve spring more than necessary to InitaU the rahv coaeri.
'ALVE SPRING COMPRESSOR
Top the valve stems gently with a soft hammer to firmly seat tho valvo cotton
NOTE____________________________
Support the cylinder head above the work bench surface to prevent possible valve damage. _________
Dateof Issue: May. 1980 ©HONDA MOTOR CO.. LTD.
67
6-11
CYLINDER HEAD/VALVE
C70
Install the camMtaft aligning the cam lobes with the cylinder head cu lout*.
Align the camshaft hole with the cylinder hood index mark lot easy rarmhofi sprocket installation.
INDEX MARK
\
HOI I
Apply a thin coat ol engine oil lo the roefcor ami (hulls,
Imtall the rockoi armi and snails with the threaded ends facing out.
ROCKER ARM
ROCKER ARM SHAFT
Install the cylinder head right tide cover using a new gatklL
CYLINDER HEAD RIGHT SIDE COVER
6-12
Date of Issue: May. 1980 ©HONDA MOTOR CO., LID.
C70
CYLINDER HEAD-VALVE
CYLINDER HEAD INSTALLATION
Install a row cylinder head gnn
l)>eintnk« sirJc. • Do not align the piston pin clip end gap wnn
!he plsion cutout.
CYLINDER INSTALLATION
Install the dowel pins, O-fino, and natkei.
GASKET
OHING
DOWEL PINS
Apply a thin coal ol angina oil la the piston rintj
end cylinder wall.
Install the cylindat, comprifM»H| 'he piston rings.
NOTE
When the cylinder is hallway over the piston, route tha cam chain through the cylinder.
7-6
78
Oeteoltuue: May, II
til HONDA MOTOR CO., LTD.
C70
CYL1NDER;PIST0N
Install the <:nm chain guide roller and tighten :¦¦* guide roller pin.
TORQUE: 0.9-1.4 kg-m (6.S-10 1Mb)
Looiely install tho 8 mm lioll.
Install the cylinder head (Section 6).
1 t
GUIDE ROLLER
GUIDE ROLLER PIN
r
Dale of Issve; May, 193(1
&HONDA MOTOR CO., LTD,
"3
7-7
~
C70
8. CLUTCH
SERVICE INFORMATION 6-1 CLUTCH DISASSEMBLY 8-3
TROUBLESHOOTING 8-1 CLUTCH ASSEMBLY 8-6
RIGHT CRANKCASE COVER CLUTCH INSTALLATION 8-6
REMOVAL 8-2 RIGHT CRANKCASE COVER
CLUTCH REMOVAL 8-2 INSTALLATION 8-7
- SERVICE INFORMATION
GENERAL INSTRUCTION
Clinch service can te done with ihe engine in the frame
TOOLE
COmmo Univeisa holder
Lock nut wrench. JO x 24 mm ixieniion. Jrt in ariwi x J in (/¦& mm>
37726-0010101 - N.A. IN U.S.A., U« commercially available
bond swap wtench. 07716-0020100 U7 M6-002UbQO - Commercially available
n
TORQUE VALUE Clutch IccK nut
X8-4.5k9m|28-33lt-n>l
SPECIFICATIONS
ITEM STANDARD SERVICE LIMIT
Clutch Soring free length 26j»mm (0.987 in) 23 1 mm (0.91 in.
Disc thick nan A 2.»-2.B5mm 10.100-0.104 lnl 2.3 mm (0.09 In,
B 3.35-3.45 mm IQ.139-0.138ln| 3.0mm iO.I2»nl
Plate warpage 0.2 mm 10.01 inj
Cluic* com trr guide O.D. 20.930 - 20.960 mm (0.8240 - 0,8248 In, 20.90 mm 10.823 lnl
Drive uear I.D. 21.000 - 21.021 mm (0.8288 - 0.8276 in| 21.05 mm )0.829inl
TROUBLESHOOTING
Clutch dipt
1. No (tee play 2 Discs /.cm 3, Springs weak
Clutch doe* not disengage 1. Plate warpnge
Clutch dragi when disengaged 1. Li fur mechanism damaged
Dateoi ssua May, 1980 ©HONDA MOTOR CO., LTD.
81
8-1
CLUTCH
C70
«
RIGHT CRANKCASE COVER REMOVAL
Drain ihe enalne oil thoroughly. Support ihe inotooge 2-21.
KICK STARTEI1 PEDAL
«9 xszzsijmr
FRONT COVER
/
*-*.
^CT
i '
MUFFLER FOOTPEGS/SIDE STAND RIGHT CRANKCASE
ASSEMBLY
CLUTCH LIFTER REMOVAL
Remove the clutch Mtw ond clutch odjuiiing bolt
COVER ADJUSTING BOLT
•
CLUTCH REMOVAL
flnmcwff ihc clutch luvur end clutch cam. Remove the dutch outer cover.
~
CLUTCH LIFTEH
CLUTCH OUTEfl COVER
"
CLUTCH LEVER CLUTCH CAM
8-2
DsM.oJIsant-- M«V, 1B80
C HONDA MOTOR CO., LTD.
C70
CLUTCH
Straighten tho lock v/zihrr wh.
LOCK WASHER TAB
9,1
*
v
Remove the lock nui, v*aMie« and lock washer. The clutch can now bo removed as a unit
Remove the drive gear and clutch center guide.
UNIVERSAL HOLDER
o
CLUTCH DISASSEMBLY
Remove the un ring uvlng a screwdriver.
Remove iho dutch plate*, discs, canter, drive gear
cuter and roller*.
Oateof Iwue: May, 1880 ©HONDA MOTOR CO., LfD.
EXTENSION
LOCK NUT WRENCH. 20 * 24mm
SET RING
8-3
CLUTCH
C70
Remove the dun-h dampiri springs.
**Iwg a wood block under lite di ive ptaie. Remove Me 5 mm screws. loosening ?-3 tunw at time while pushing tlnwn on the clutch outot.
*
'-
-
CLUTCH SPRING INSPECTION
Measure tin? spring ln'ii length.
STANDARD; 25-08 mm 40.987 in| SERVICE LIMIT: 23.1 mm (0.91 In)
CLUTCH DISC INSPECTION
Replace the clutch discs i' they show Wgm ol scoring or discoloration. Measure the disc thickness.
STANDARD:
DISC A; 2.66--2.65mm (0.100-0.104 in) DISC 8: 3.35-3.45 mm 10.139-0.136 In)
SERVICE LIMIT: DISC A; 2.3 mm (0.09 in) DISC B: 3,0 mm t0-17 In)
8-4
Dat8 of Issue: May. 19H0 ©HONDA MOTOR CO.. LTD.
C70
CLUTCH
Chock the rollei& and plates for excessive wear Replace if necessary.
Chock to' olate warpec* on a turfaco plate using .1 fee-lor gauge.
SERVICE LIMIT: 0.2mm (0.01 in»
n
DRIVE GEAR INSPECTION
Check lot wear or ctema)e. Mfie&ure I he drive gear I.D.
STANDARD: 21.000-21.021 mm 10.8268 -0.8276 in»
SEHVICE LIMIT: 2105 mm (0.829 in)
CLUTCH CENTER GUIDE INSPECTION
Check (or wear or damage.
Measure the dutch center guide 0.0.
STANDARD; 20.930-20.950 mm <0.8240-0.8248 in)
SERVICE LIMIT: 2090 mm 10.823 in)
DateoHssie: May, 1980 ©HONDA MOTOR CO.. LTD.
8-5
CLUTCH
C70
~
CLUTCH ASSEMBLY
Place the clutch springs on ihr driwe plulc and Insral the drive plain to ihe dutch outer.
NOTE
Tlflhlsn the screws In 2-3 steps in a crisscross pa nem,
Instill the clutch damper spring*-
Install the tollers, drive gnat outer, clutch eenui. discs and plates And secure with the set ring.
CLUTCH PLATE A FRICTION ,., irrru
DRIVE GEAR 0|SC Q ^L'J^Hn
ROLLER
OUTER
CLUTCH CENTER
PLATE B
SET
CLUTCH DRIVE PLATE SPRING FRICTION DISC A
r>
CLUTCH INSTALLATION
Install Hit- clutch center guide and delve gent
Install the clutch aiserni.lv.
Install the lock washer, plel" v/other and lock nut
NOTE
Install the plain washer with the "OUTSIDE" mark facing out
PLAIN WASHER
r\
~~
Tiehten the lock nut
TORQUE; 3.8-4.5 kB m (28-33 fl-lb)
Bend the lor* washer tab,
LOCK NUT WRENCH, 20 x 24 mm
EXTENSION
UNIVERSAL HOLDER
TORQUE WRENCH
8-6
86
Daieof Issue May. 1980 ©HQNDA MQTOR CO., LTD.
C70
CLUTCH
Install the clutch outer covet. Install the dutch cam and lever.
Install iha fpring. oil through. dutch cam spring and ball retainer.
ClUTCH OUTER COVtR
OIL THROUGH
CLUTCH LEVER CLUTCH CAM
RIGHT CRANKCASE COVER INSTALLATION
Install thn clutch adjusting twit and IHler.
ADJUSTING BOLT
CLUTCH LIFTER
r
r
Install the O-ring. washer and lock nut.
Install the tight erankcase tovei.
Install the kick narwr pedal. tooipegt/i>de stand
aHomblv, muffler and front cover.
Fill thn crankcase to the proper Icvol wth the
¦ecommended oil (page 2-21-
Adjust thu dutch (page 3-16).
O-RING WASHER LOCK NUT
Date of Issue May, 1980 ©HONDA MOTOR CO., LTD.
87
8-7
GEARSHIFT LINKAGE
r
C70 ^y
9-0
Oaiciil Irauo: May, 1980 ©HONDA MOTOR CO., LTD.
/¦\>,
C70
9. GEARSHIFT LINKAGE
SERVICE INFORMATION TROUBLESHOOTING GEARSHIFT LINKAGE REMOVAL 9-1 9-1 9-2 GEARSHIFT LINKAGE INSTALLATION 9-2
SERVICE INFORMATION
GENERAL INSTRUCTIONS
• The oearshif I spindlii and stopper arm can be serviced with ihe engine In thu frame.
• II iho shift fork),, drun and transmission requite servicing, remove ihe engine and separate the crarkcate.
TROUBLESHOOTING
H«f« shifting
1. Impfooer dutch adjustment
2. Shift forks tenl
3. Shllt shaft bam
4. Shift dium stopper bant
6, Shift drum cam Brooke beni
Ttettsmmion |umpi out of gear
1. Qam dogiworn
?- Shift shaft beni
3. Shift drum stopper woken
«. Shift forks beni
Dale of Issue: May. 1S6Q "" Q-1
©HONDA MOTOR CD. LTD. 9 l
GEARSHIFT LINKAGE
C70
GEARSHIFT LINKAGE REMOVAL
Drain tho engine oil. Remove the gearshift pedal.
GEARSHIFT PEDAL
Remove the right etdnkcass cover and dutch »¦ terribly {Section Bl.
Remove the snap ring and driven
DRIVEN GEAR
SNAP RING
Remove the drum stopper arm.
DHUM 5TOPPER ARM
9-2
Dnleol Issue: May, I960 ©HONDA MOTOR CO., LTD.
V C70
GEARSHIFT LINKAGE
DRUM STOPPER PLATE
Remove tho drum *Iopp;i iilitle anil pins. Pull rhc gearshiti spindle out ot ihn crankcaio.
GEARSHIFT LINKAGE INSTALLATION
Install the Qeinhllt dium pins and dium stopper plate.
DRUM STOPPER PLATE
Install the gea'thih sphdm assembly.
GEARSHIFT SPINDLE
if:t;r.' skjPPFR i-ir/
Install the drum nopptr aim as shown. Tighten the p«woi bolt.
Rotate the gearshift soindle and chert the linkage for smooth operation.
Install (he clutch asiembly and right crankcosB cover.
Install Iho gearshift pedal.
Date ot Issue: May. 1980 ©HONDA MOTOR CO., LTD
91
9-3
TRANSMISSION/CRANKSHAFT
C70
l.O-Mkg-m (7- 101Mb)
10-0
92
DjicoIImuo; May, 1980
© HONDA MOTOR CO., LTO.
:¦>
H plav
2. Excessive cr^kpin bearing play
1Q.O Dawoft*sue: Mav. 1980
©MONOA MOTOR CO., LTO.
-
C70
TRANSMISSION/CRANKSHAFT
CRANKCASE SEPARATION
Remove ihe engine (Sectun 51. Remove the cylinder head (Section 6}. Remove the cylinder anil pinon (Section 71 Remove the clutch (Snctfen 8). Remove the gearshift linkage (Section 91. Remove the starting mot'W ISociion 161. Remove the A.C. generator (Section 14). RBmovo the crankshaft ewer. Remove the drive sprocket
CRANKSHAFT COVER
Remove the cam chain •omionor rod and teowoner. Remove the ruhber capond ihitt drum mounting 6 mm bolt Romove ihe ciankcase 6mm ww,\.
CAM CHAIN
TENSIQNER
SHIFT DRUM SHIFT DRUM
RUBBER CAP BOLT
CAM CHAIN TENSQNER PUSH ROD
Place ihe engine with trvt left aankcase down. Remove the *wip ilng tion remove the retainer and kick startet toimg.
RETAINER
¦'
SNAP RING
*
LN
KICK STARTfH Sl'RING
»-*
Daieotluue: May. 1930
a HONDA MOTOR CO., LTD.
95
10-3
TRANSMISSION/CRANKSHAFT
C70
t the tight ctankcaie from the lelt awktatu-Reinove the dowet pint and gaskot.
CRANKSHAFT REMOVAL
Remove the crankshaft.
CRANKSHAFT INSPECTION
Set tho crankihaft on a Hand or V blocks.
Sot *mWe the kick ilaiter spindle.
Check the driven ratchet. pinion and spindle for excesilve >
SPINQI E
PINION SNAP PING RATCHET SNAP RING
10-6
Date of Issue: May, 1980 ©HONDA MOTOR CO., LTD.
^
C70
TRANSMISSION'CRANKSHAFT
TRANSMISSION GEAR DISASSEMBLY
DiWBcmHo the mainthad -mo countershaft. Inspect each gear for wear or damage
COUNTERSHAFT FIRST GEAR SECOND GEAR THIRD GEAR
\ I / I
MAINSHAFT SECOND GEAR THIRD GEAR
Measure orf. yeai'-. l.D.
STANDARD: 17.018-17,043 mm 10.6699-0.6710 inl
SERVICE LIMIT: 17.10 mm 10.673 in)
<"
Mpi»um the 0-D, ol the mMnshaft and counter-ihaft.
STANDARD;
MAINSHAfT: 16.983 -16.994 mm (0.6686-0.6691 »nl COUNTERSHAFT: 16.966- 16.964 mm (0.6680-0.6687 ml
SERVICE LIMIT: 16.95 mm (0.667 ln|
Date of Issue: May. 1960
S HONDA MOTOR CO., LTD,
10-7
TRANSMISSION/CRANKSHAFT
C70
r.
u
K
SHIFT DRUM DISASSEMBLY
Remove the guide pin dipt, pull out tbo guide pins and remove ibu shift torts.
NOTE
GUIDE PIN CLIP
Mark the right and left shift forks io ensure correct aswmbiy.
Check ihc guide pin for wear 01 damage.
GUIDE PIN
Check Ov. shift fork lor wear, bending or other
dtnugt.
hteasure ihe ihift fork 1.0.
STANDARD: 34.000-34.025 mm 0.3386—1.3396 In)
SERVICE LIMIT: 34.07 mm (1.341 in)
")
~
tt
Measure ihe shift fork claw mlckness.
STANDARD:
LEFT: 4.86-4.94 mm (0.191-0.195 in) RIGHT: 5.86-5.94 mm (0231-0.234 Inl
SERVICE LIMIT:
LEFT: 4.6 mm (0.18 Inl RlGHT:5.6mm!Q.?2in|
10-8
100
Date o'iff.-B- May, 1980 ©HONDA MOTOR CO., LTD.
C70
TRANSMISSION/CRANKSHAFT
Check the shift druni foi wear or daiia^o* Measuie the shift drum 0.0.
STANDARD: 33.9EO-33.97B mm (1.3366-1.3370 in)
SERVICE LIMIT: 33.93 mm (1.336 in)
TRANSMISSION ASSEMBLY
Assemble the mainshafi and countershaft gean and secure with the snap rings.
NOTE
r
Lubricate each asjemWy.
with angina oil aftei
SECOND THIRO
COUNTERSHAFT FIRST QEAR GEAR GEAR
.\ J
^|
o
t
*
/,
o
MAINSHAFT SECOND GEAR TMIPC GEAR
SHIFT DRUM ASSEMBLY
Innall tho ihilt fort, an Ox shift drum Install tho BUida pinj and secure with the clips.
RIGHT SHIFT FORK
LEFT SHIFT FORK
SHIFT DRUM
GUIDE PINS
Date of Issue' May. 19(0 ©HONDA MOTOFt CO., LTD.
101
10-9
TRANSMISSION/CRANKSHAFT
C70
¦)
KICK STARTER SPINDLE ASSEMBLY AmcmbJo the kick itarter as shown
NOTE
Position the friction spring in the driven ratchet groove.
KICK STARTER SPINDLE
FRICTION SPRING
KICK STARTER PINION
SNAP RING
STARTER RATCHET
TRANSMISSION INSTALLATION
the drum and transmission In r« left as an assembly.
NOTE
• Al'ftt the neutral twitch rotor with the
neutral switch. - After Installing, rotate thn mainthalt lo mate
sure thai The gears rotate freely
rV.AINSHAFT
COUNTERSHAFT
^NEUTRAL
ITCH ROTOR
NEUTRAL SWITCH
HHUST WASHER
Install ih« kick starter spindle so ili-at the friction spring rests in tho crankraw groove.
GROOVE
FRiC'O'J SPRING
10-10
102
Dotcol Issue: May, If
£> HONDA MOTOR CO., LTD.
C70
TRANSMISSION/CRANKSHAFT
CRANKCASE ASSEMBLY
Install the crankshaft ino the left crankcase.
lii-staH ihe dowel pira and gat kot.
Place the rlghi cronkesw onto the left crankcase and luin ihe crankcase assembly over.
Install and tighten the cankcai* strews.
DOWEL PIN
GASKET
\ ?
DOWEL PIN
Install ihe cam chain, «nsinn«t and inmionor rod,
Install Ihe ihlll dium B mm mounting boll and robber cap.
Install Ihe tiiwl drive sprocket.
TORQUE: 1.0-1.4 kg-m (7-10 ft-lb)
CAM CHAIN SHIFT DRUM SHIFT DRUM
TENSIONER RUBBER CAP BOLT
\
CAM CHAIN
TENSIONER PUSH ROD
Install the kick Manor spring and retainer.
Hook the spring ends in lha retainer groove and over
the crankcase protection.
Install the map ring.
Inttall the A.C. generator (Section 14). Install the starter motor {Sect)on16}. Install the gearshift linkage (Section 9). Install the duich (Section 8(. Install Die cylinder and piston (Section 71. Install the cylinder head (Section 61, Install the engine (Section 5}.
UCK STARTER SPRING
SPRING RETAINER
Date o'Issue; May, 1980 ©HONDA MOTOR CO., LTD.
103
10-11
HONDA/'^ C70 ^J
MEMO
¦
104
DdtCOf Iwuc: May, 19R0 ©HONDA MOTOR CO., LTD.
r
C70
CAM CHAIN
11 OHIYI bflHIi l. TENSIONER
SERVICE INFORMATION TROUBLESHOOTING
11-1
n-i
CAM CHAIN TENSIONER PUSH ROD
CAM CHAIN TENSIONER
11-2 11-3
SERVICE INFORMATION
GENERAL INSTRUCTION
The cam chair* irmiomr and push tod can be serviced wiitt the engine in iha frame.
TROUBLESHOOTING
Cam chain noiM
I. Incorrect lensloner adjustment
?. Damsaed ipring
3. Wnrn or ilamjjrU ipruckal
4. Worn or damaged chain
of Issue; May. It HONDA MOTOR CO., LTD.
105
11-1
CAM CHAIN TENSIQNER
C70
fr
CAM CHAIN TENSIONER PUSH ROD
Drain dw tntfm ««!¦
Luown the lock nut and remove iho lock bait.
Remove thp sealing holt and wuriwr.
Remove the adjusting bolt. tpiinni and lemioner toil.
Check tho tonslonei rod and spring tot damaoe
ADJUSTING HOLT
SEALING BOLT
LOCK NUT
trnttf) the tensioner push tod with the taper facing lock lioll.
Install lhi> springs.
Screw adjusting bolt into Mm cianfcciisti
Install thi- waling washer and bolt
NOTE
The sealing. bolt end must not contact the boiiom of the adjusting bolt
Install lock bolt and loch nut. Tighten tho lock nut.
SEALING 80LT
ADJUSTING BOLT
11-2
lit-,
Oateof Issue. May. 1980 ©HONDA MOTOR CO.( LTD.
C70
CAM CHAIN TENSIONER
CAM CHAIN TENSIONER
Remove thn A.C gcnmtm anil flywheel (Section 14).
Remuvi! 'r-.i; lunar chain guide.
Remove the naiur chain eroieiiio*.
Remove (he starrer sprockets anil chain m a unit
Remove the crankihatt cover.
CHANKSHAFT COVER
Q-RING
CAW CHAIN TENSIONER
Remove- the 'eititnnet push tod.
Remove the cem chain ttmloner,
deck thn WthMl suiockei lor wear or damage*
Insiallaiioo Is (he ravmt of removal.
NOTE
Be sure to install 0-rinpi on the crankshall covet screw holm,
Dated Issue: May, 11 ©HONDA MOTOR CO., LTD.
107
TENSIONER PUSH HOD
11-3
FRONT WHEEL/SUSPENSION
C70
6-0 -9.0kg*m c (43 - 65 ft-ft>| t
3.0 —1.0' k|jm (22 - 291 Mb)
1.0 - 2-0 kn-m |7-14)t-lb)
2.5 - 3.5 kg-m U8-25fl-lb)
2.0 - 3.0 kg-m H4-22IMW
12-0
Daieotlviuc: May, 1980 ©HONDA MOTOR CO.. LTD.
"
r
C70
10 FRONT WHEEL 12. SUSPENSION
SERVICE INFORMATION
TROUBLESHOOTING
HEADLIGHT
INSTRUMENTS
1 12-1 HANDLEBAR 12-5
12-2 FRONT WHEEL 12-8
12-3 FRONT SHOCK ABSORBER 12-12
12-3 FRONT FORK/STEERING STEM 12-16
SERVICE INFORMATION
GENERAL INSTRUCTIONS
• A jack or other support It requlied to support the motorcycle.
• Route all cables and win>i proporly (page 1-6).
r
TOOLS
Special P|n i|i an i *s« Ball race temovet
Common
Bearing driver handle A
Bearing driver outer, 32 x 35 mm
Bearing driver pilot. 10 mm
Lock nut wienph, 26 x 30 mm
Extention bar, 1/2 in driw x 3 In (75 mm)
07903-0010000
17946-1790001) - M9310-277-B1774, U.S.A.only
0-/946-9370100
07749-0010000 - 07949-6110000
07746-0010100.
07 746-004010D
07716-0020202
07716-0020500 - commercially available
TORQUE VALUES
Sto«inQ*temnui
Handlebar setting nut
Steering lot*
Front axle nut
Front (uuxtnuuri pivot boll
Front suiparrtioo stopper bolt
Front shock absorber upper boll
6.0 - 9.0 kg-m 2.0 - 3.0 kg m 0.6 -1.3 kg-m 3.0-4.0ks-m 1.0-2.0 kg-m 2.0-3.0 kg-m 2.5 - 3.6 kg-m
(43-66(t-lb| |M-22rMb> (4-10 M-lbJ (22-29ft-lb) ( 7 — 14 li-lb) (l4-22ft-lb) (18-25ftH»l
Oateof loue: May. 1980 ©HONDA MOTOR CO.. LTD.
12-1
FRONT WHEEL/SUSPENSION
C70
SPECIFICATIONS
STANDARD SERVICE LIMIT
Wheel bearing play 0.03mm (0.001 in) 2.0 mm 10.08 InJ 2.0 mm (0.08 ml
Finnt wheel runout Radiol Axial
Front nxlo wiout 0.2 mm (0.0lin)
Front brake drum I.D. 109.6 - 110.2 mm (4.32 - 4.34 ln| 111mm (4.4 in!
Front brake lining thickness 3.8-4.0mm (0.154-Q.1B8in) 2.0 mm (0.08 in)
Front shock absorber soring free length 170.B mm (6.72 in) 165.6 mm (6.52 in|
Suspension arm pivot bushing O.D. 13.96 - 13.98mm (06SD- 0.551 In) 1355mm (0.533 InJ
Suspension Arm pivot collar l,D. 14.00 - 14.10 mm 10.551 - 0.555 In} 14.47 mm (0.570 In!
Shock lower mount bushing O.D. 11J»-1IJ8mm HM71 - 0.472 inj 11.61 mm (0.457 In)
Shock lo»«6' mnunl collar I.D. 12.00- 12.10 mm (0.472-0.476 ini 12.41 mm(0/48BInl
TROUBLESHOOTING
Ha id ¦ v.-- ¦ ..
1. Stee*ing stem bearlrvg adjusting nut too tight
2. Fiulty steering stem beatings
3. Damaged steering stem bearings
4. Insufficient tiro pressure
Stasis lo ona *id* or does not track iu light
1. Faulty right or led shock ahsorbe*
2. Bent Irani fork arm
3. Bant fronf **ls: wheel Installed incorrectlv
Front wheal wobble
1. Distorted flm
2. Worn front wheel bearings
3, faulty tire
4, Axle iwt lightened properly
5. Worn front suspension arm bushing
6, Loose or Rent ipokes
Soft suspension
1. Weak shock absorber soring
Stiff suspension
1. Lack of sreaw '" suspeiulon arm bushings
Front suspension noise
1. Worn suspension arm bushings
2. Damaged rebound stoppei
3. Loose shock absorber fastener*
4. Lack of gwase in suspension arm bushings
5. Lack of grease in speedometer gear housing
12-2
110
Dale ol Issue: May, 1980 ©HONDA MOTOR CO., LTD
C70
FRONT WHEEUSUSPENSION
HEADLIGHT
REMOVAL
Remove ihe Headlight mounting scrowi.
Disconnect tho headlight wire conneeion and remove Uis headlight.
DISASSEMB LY/ASSEMB LY
Remove tna horuoniai andvcticai adjuring tcrowi !rom the nm.
Remove tho clip and walod Imam unit retaining •ciew, and Mated beam unit
Assembly i* the reverse ol diia»e(nblv. After aiMmbly, adjuif the headlight beam (cage 3-151.
INSTRUMENTS
REMOVAL
I*'-"-.,,., ¦¦•i- hnnilhyhl.
Remove ihe handlebar mounting nuts.
SEALED BEAM RETAINING SCREW
HORIZONTAL ADJUSTING SCREW
VERTICAL ADJUSTING SCREW
Dateot issue: May, '980
£*HONDA MOTOR CO., LTD.
Ill
12-3
FRONT WHEEL/SUSPENSION
C70
Raise the handlebar anil remove the speedometer selling spring.
Disconnect iho speedometer cahln.
NOTE
Do not alio* the cable out to fall into The steering iiitm.
Disconnect the ipiwoometer flrvd indicator bulbwlie connecioi*.
Hnmo'B Ihe speedunirflet,
SPEEDOMETER CABLE
SETTING SPRING
Romovo the bulbi MOTE
SPEEDOMETER LIGHT
If a. replacement bulb don not light, choc* tho wiling for a short or open citcuit. or for looto connections,
INSTALLATION
install the speedometer with Ihe letting spring. Install the handlobar,
HIGH 8EAM INDICATOR
TURN SIGNAL INDICATOR NEUTRAL INDICATOR
12-4
M2
Date of luue: May, 11
O HONDA MOTOR CO., LTO.
C70
FRONT WHEEL/SUSPENSION
HANDLEBAR
REMOVAL
Remove the headlight. Disconnect the speedometai' wins.
Removu the tight handlebsi witch mounting
screw*
r-
Disconnect the th'ottfe cable end nnd reirnw the throttle 91 p.
THROTTLE CABLE END
?die of Itxiie: M.-iy, 1980
OHONDA MOTOR CO.. LTD.
113
12-5
FRONT WHEEL/SUSPENSION
C70
Remove Lhn IHt handlebar twitch tnuunungsciewi. Remove. ihe minors.
Remove the turn Hgnuti
Remove the left grip.
Remove the liandleDsr mourning ngti
Raiso the hanitlabst and unclomp th* wiring hat-nesw*.
Remove t*ic u>aedc*neter wiling spring and speedometer,
Remove the Handlabar assembly,
HANDLEBAR MOUNTING NUT
INSTALLATION
Install the lelt grip.
Install The loeedomstei into the handlebar with the letting wring.
Clamp wo wiring harnesses mio plain.
Plow thn hawilebar on its mount and co-meet the speedometer cable.
Install the hamlleiwr mtMiiling nuts.
TORQUE: 2.0-3.0 hg-m 04-22 ft-lbj
install the mirrors,
TO
HANDLEBAR MOUNTING NUT
~
"
12-6
114
Dateof Issue; Mav. 1980 ©HONDA MOTOR CO.. LTD.
C70
FRONT WHEEL/SUSPENSION
Install the left hsnfflebat switch mounting sctewi, Apply grime it. the throttle grip sliding iurlnc«. Connect the throttle cable end to the throttle
THROTTLE CABLE END
Align the right Handlebar iwiich lang with tne
*.., rC'v.i -i -i-:: „m: ,ii;t.i:I T*,r ¦,vj.;[;h
RECESS
tANG
Imtail thp hoarjlipht {page 12-3} and connect soopdometer wires.
Ad|u»i throttle caliio free play (page 3-3).
SCREW
DUST COVER
NUT
Dfltciof loun: Moy, I960 ©HONDA MOTOR CO., LTD.
lis
12-7
FRONT WHEEL-SUSPENSION
C70
FRONT WHEEL
REMOVAL
Raiw Hio front wheel of the gtound by placing a luppoti block under iheengina-
Luoien '.he ioaedomovir c»We nut ood remove the tpccdomele' cable.
Remove die from brake adjusting imi 4111) disconnect the brake cable irom ihe brake arm.
SPEEDOMETER CABLE
RAKE ADJUSTING NUT
Remove the toller pin and loown Ihn oxlo nuU Remove the from axle. Rcmovo the- (root wheel.
AXLE NUT
COTTER
WHEEL BEARING INSPECTION
Check wnool bearing ploy bv placing the whool in a truing stand and spinning lha wheel by hand. Replace ihn bearings with new one* if they ore noity or have excessive pl«y.
SERVICE LIMIT: Q.03 mm (0.00) ml
12-8
116
Daw of Issue: Mnv, ItSfli)
©HONDA MOTOR CO.. LTO.
m
C70
FRONT WHEEL/SUSPENSION
WHEEL BEARING REPLACEMENT
Remove the seal.
Remove the tw.5r.ngi and distance eollor from tN> hub,
WHEEL BEARING
SEAL
n
Pack the beating with grease. O'ivp in ffw 'ight broilng fust. Pieis tho distance collar into placo
NOTE
Be ei-ii 11 the distance colla- it in position boforo in«tallir>g the IrIi tx>a:.ng.
Oilwe In the left bearing. NOTE
DtivB tha boa'ingt squarely. Drive ttw bearing into position, making suie that it li fully seated and that the waled tide is facing ou I
BEARING DRIVER HANDLE A - 0794961IO00O BEARING DRIVER OUTER. 37 - 35 mm SEARING DRIVER PILOT1, 10 mm
- 0/9.16-9370100
Install (he seal.
WHEEL INSPECTION
Check ihw Hm runout by piscing the wheel in a truing stand. Spin tho wheel slowly and read die runout using a dial indicator.
SERVICE LIMIT:
RADIAL RUNOUT: AXIAL RUNOUT:
2.0 mm (0.08 In) 2,0 mm (0.08 in)
Datcol l«ue: May. lS60 ©HONDA MOTOR CO.. LTD.
117
12-9
FRONT WHEEL/SUSPENSION
C70
AXLE INSPECTION
Set the axle in V l>lm-J« and rfleWJtQ the f urtntll-
The actual runout is 1/2 of the total ndicato-wading.
SERVICE LIMIT: 0.2 mm (0.01 in)
7A ^^S\ \
vV^\
I™"j tr*
BRAKE DRUM I .D. INSPECTION Measure the brake drum Imide diameter. SERVICE LIMIT: 111 mm (4.4 |n]
BRAKE LINING THICKNESS INSPECTION Measure the tiiako lini np thidcnew. SERVICE LIMITt ?.0 mm 10.06 i"»
12-10
118
Date uf Issue. May, 1980 ©HONDA MOTOR CO., LTD,
C70
FRONT WHEEL/SUSPENSION
BRAKE PANEL DISASSEMBLY
Remove the C*eke arm, indicator plow and return wring,
Remove the brake shoos and brute din.
flrmiwu iho MWedomateri
Remove (ho toa.1,
BHAKE PANEL
INDICATOR PLAT
SPEEDOMETER GEAR
BRAKE CAM FELT SEAL BRAKE SHOES
ARM SPRING
BRAKE ARM
BRAKE PANEL ASSEMBLY
Apply grease lo the speedometer gov ami Install the dear.
Install the seal.
SPEEDOMETER GEAR
SEAL
•
SHOE SPRINGS
Apply grease to tho sliding mi face of the rxaku cam. Install the brake cam.
1'iitall the brake shorn and shoe spring*.
* WARNING
Coniamlnaied brake Uninm irduee slopping
paver,
Keep grease off the lining.%
IRAKE SHOES
DatooftBue: May. 1980 ©HONDA MOTOR CD, LID.
119
12-11
FRONT WHEEL/SUSPENSION
C70
Install the 'eli seal.
Install ihe wear indicator plate.
NOTE
Allan thfl Indicator plant Inner tab with me
CK'ii! Of III)- iK.ikr. Uffl.
Install the b-akaaim and tciutn spring. NOTE
Alltfn Ihe pur-ch murk*.
Tightcn thfl brake arm holi and nut.
INSTALLATION
Install)** t'oni wheel batween the fork leg*.
NOTE
Make aure the long on ihe righi suspension arm li located in the groove of the brake pamrl.
Iniioil Ihe axle shafi Irom iho right side.
Tighter- iho axle nut.
TORQUE: 3.0-4.0 kgm (22-29 ft-lbl
Install a new cotter pin.
Coned ihe frpni h'aka sod ipeedormrter cables.
Adjust the from brak.- {page 3-14J.
SHAKE ARM
PUNCH MARKS
INDlCA
Hi.II.-RM SPR'NG
AXLE NUT
BRAKE CABLE BRAKE ADJUSTING NUT
COTTEH PIN
FRONT SHOCK ABSORBER
REMOVAL
Heroove the front wheat (page 12-6).
I'.-mv Iho front shock a blotter and lebound stopper mounting bolts and nuts.
RcmovD inf shock atnorbon.
12-12
120
Date of issue: Mav, I9fii: ©HQNDA MOTOR CO., LTD.
C70
FRONT WHEEL/SUSPENSION
DISASSEMBLY
Rnmove the lower ihock absorber mounting bolt and scpiimic the suspension i»"n liom the shock absorbs'.
SUSPENSION ARM
SHOCK ABSORRfR
flemwn I'm duil caps and ditasscmblo the suspen-
¦ii| ,1TT
DUST SEALS
SUSPENSION ARM
BUSHING
. OUST CAPS
®«#®
BUSHING
GREASE FITTING
SHOCK ABSORBER INSPECTION
Inspect the shock body fat oil leaks. MflstUfA 'lie l'«e Imirjth of spring. SERVICE LIMIT: 166.6 mm 16.62 in)
PREE LENGTH
04umumutu
DiteOl IMuk May,1980
O HONDA MOTOR CO., LTD.
121
12-13
FRONT WHEEL/SUSPENSION
C70
SUSPENSION ARM BUSHING NSPECTION
Medium iho bushing. outside diameter.
SERVICE LIMIT:
SUSPENSION ARM PIVOT: 13.55 mm (0.533 in!
SHOCK LOWER MOUNT: 11.61 mm (0.457 ml
Measure the bushing collar inside diameter.
SERVICE LIMIT:
SUSPENSION ARM PIVOT: 14.47 mm (0.670 In) SHOCK LOWER MOUNT: 12.41 mm (0.489 inl
ABM PIVOT SHOCK LOWER MOUNT
ASSEMBLY
Assemble irta tusponiion arrm
Peen nach wspimsio" arm pivot dull cap m throe
i-l.
; tftDWtti
I't-LN
Install the suspension arm to the shock niwo'ber and tiflhien uto bolt and nut.
SUSPENSION ARM
.
SHOCK ABSORBER
12-14
12?
Oateol Issue: May, 1980 ©HONDA MOTOR CO., LTD.
C70
FPONT WHEEL/SUSPENSION
INSTALLATION
InsUM ">n shock absotbws. TORQUE:
UPPER MOUNT BOLT:
2.5-3.5 kij-m (1B-25 fMbl SUSPENSION ARM PIVOT NUT:
1.0-2.0 kg-m (7-14 ft-lbl Install the rebound Hopper*.
TORQUE: z.0-3.0 kg-m 04-22
UPPER MOUNT
SUSPENSION ARM PIVOT
REBOUND STOPPER BOLT AND NUT
NOTE
Position :tto rebound stopper at thovm
Install ttw front v/twel (page t2-1?). Liitvicatn thn suspension arm plvota.
/
GREASE FITTINGS
Dale of Irup: May. 1980 ©HONDA MOTOR CO., LTD.
i ?:i
12-15
FRONT WHEEL/SUSPENSION
C70
FRONT FORK STEERING STEM
REMOVAL
Remove Iho handlebar {page 12-51. Remove :*i6 tloi>l wheol (page 12-81.
Remnw) ihothock absor bgri ipogc 1? 12). flomovetlie BrofM iondflt. Remove the from carrier. Remove the front upoer cover.
Oiicoinccl the choke cnMc at the carburetor. Remove the choke knob letting Krew and remove ilie choke cabla. Remove the :hrottle. brake and ipwdometer cablof,
FHONT UPPER COVER
CARRIER
FRONT FENDFR
CHOKE CABLE
Remove thr top bridge mounting bolt*.
12-16
1Z*
Dauof l*we: May. 1980 ©HONDA MOTOR CO.. LTD.
C70
FRONT WHEEL/SUSPENSION
Remove Ihesteering. slnm nui. L0CK NUT WRENCH. 26 x 30 mm
Ramovc the lop Iwidge. mounli and handlebar EXTENSION HANDLE AND BAR law cover
Remove the tearing adjusting nut.
Remove Ihe front fork. uilper cone tots and steel ball;.
PIN SPANNER, 07902.001O00G 36 mm f
Jr^
8
^
LOWER CONE RACE REPLACEMENT
Remove the lower cone race, dim leal and washer.
Install a nm oust mat and tvaanqr.
Drive a new lower cone 'ace over me stem.
.'
*f*
<*z^
LOWER CONE RACE
Darn of l»uc: May, 198l> ©HONDA MOTOR CO., LTD.
125
12-17
FRONT WHEEL/SUSPENSION
HONDA
C70
BALL RACE REPLACEMENT
Remove the lower ball mi*: with iho special tool.
BALL RACE REMOVER
17946 1700000. USA ONLY MB310-27791771
Rfimovn ifiij uppni hall race with the same tool NOTE
If the motorcycle has been involved in an accident, examine thn nitta arpund lt>n Mewing head (or cracks.
Drive th* upper ball race Into ihe steering head with die special tools.
Drive the lower bail iace »nto the steering head with the same toots.
Apply a coal ol bearing grease ic Iho upper boll race and Install 21 strwl balk.
Applv a coat of bearing greaie lt> the lower boll'ac» and insuii 21 sieel bulk.
Insert the jioKring item into the steering dead ami imtail the upper cone iace and bearing adjusting nut.
12-18
126
Deteot Issue: May. 1080 ©HONDA MOTOR CO.. LTD.
C70
FRONT WHEEL/SUSPENSION
Tighten Iho ad)uuing nut until mug agitirat the uppe> cone race,
Than, loosen It 1/8 turn.
Check that theie it no vertical movement and thai Iho stem rotntei licflly.
BEARING ADJUSTING NUT PIN SPANNER 079Q2-0010000
Ir-Utfil the handlebar lower cover, top Pudge mounts and top bridge.
Tighwtn the steering item nut-
TORQUE: 6.0-9.0 kfl-m (43-66 ft-lb)
LOCK NUT WRENCH, 28 ¦ 30 mm, EXTENSION BAR
Install the top bridge mount bolts,
Route the ipeedomewr, chofcn and throttle cable*
2.0-3.0k5-m (l4-22fi-lb,
3.0-4.0fcg-m (22-29ftlbl
SPECIFICATIONS
STANDARD SERVICE LIMIT
Rear axle runout 0.2 mm (0.01 in|
Wheel Wiring play 0.03 mm (0.001 In,
Roar ivhncl runout Radial Axial 2.0 mm (0.08 m) 2.0 mm (0.03 In)
Rear br.ike drum I.D. 109.8 - 110.2 mm (4.32 - 4.34 inl 111mm (4.4 InJ
Rear brake lin-nfl thicknesi 3.9-4.0mm {0.15 - 0.16ml 2.Q mm (0.08 in)
Rear shock absorber Hiring free length 219.3 mm (B.63 In) 210.5 mm (8.30 In)
DalUil lw_e
>r/
©HONDA MOTOR CO., LTD.
129
13-1
REAR WHEEL/SUSPENSION
TROUBLESHOOTING
Oscillation
1. Bant rim
2. Worn re*i wheal beating
3. Loose or Mm spuktts
4. Foully lire 6. Loose axle
6, Tire immsu-b incorrect
7. Swinoarm bushing worn
Soil suspension
t. Weak shock absorber springs
2. Shock absorber leaknge
Hard suspension
1. Bent shock absorber
2. Lack ol grease in swingatm bushings
Suspension noise
1. Shock case binding
2. Loose fasteners
3. Worn nvingeim bushings
¦1 3_0 13° Daieof Issue: May, 1980
©HONDA MOTOR CO.. LTD.
C70
REAR WHEEL/SUSPENSION
REAR WHEEL
REMOVAL
flaiw Ihe rear whet! oil the gr*wr>il liy placing .1 support block un*it the motorcycle.
Rwnovo the loar (Hake adjusting nut and disconnect the biaks rod tram the brake arm.
Disconnect tho brake Torque link" from itw brake panel.
Loosen iho drivB chain adjusting nutt.
8 RAKE ADJUSTING NUT
DRIVE CHAIN ADJUSTING NUT
BRAKE ROD
BRAKE TORQUE LINK
Remove Ihi' collar pin lirim lho rtfor uxlo nut. Remove the axle nut and pull out the axle Remove thowhwl.
i --
\
COTTER PIN
AXLE NUT
r
AXLE INSPECTION
Set the axlo in V blocks and read ibej oxln -unouL
Tho actual axle runout Ft 1/2 of Tlfl |Tot»l
Indies 10(Rcgilingl.
SERVICE LIMIT: 0.2 mm |0.0l In)
Da:eal Iehjc: May. 1980 ©HONDA MOTOR CO., LTD.
131
13-3
REAR WHEEL/SUSPENSION
C70
WHEEL BEARING INSPECTION
Chock wheel Ixtariwj play by placing the wheel in a truing itand ond spinning the wheel by hand. Replace the bearings with new ones if they are noi*y or have exceui'e play. SERVICE LIMIT: O.03mm (0.001 in!
WHEEL BEARING REPLACEMENT
Remove the bearing and dinanca collar from hub.
WHEEL BEARING
r>
N r
Puck the bearing with peaie. Drive in tho right hearing llr»L Press Hw uisuiicc collar Irtio place.
NOTE
• Driv" the bearing squarely.
- Drive the bearing Into portion, making sure
ihe it it fully Mated and that the teaied side
Is facing out.
BEARING DRIVER HANDLE A - 07949 3O0(X)0O BEARING DRIVER OUTER.37 * 40 mm .. BEARING DRIVER PILOT. 12 mm
Q7e'-.t-O0B00O0
m
13-4
132
Date of I we May. 1980
GHONDA MOTOR CO., LTD,
C70
REAR WHEEL/SUSPENSION
WHEEL INSPECTION
CIks* ittii fim ruouul by placing (h* wheel in a Filing, stand, Spin tho wnMl slowly and read ins lunoui using a dial indicator.
SERVICE LIMIT:
RADIAL RUNOUT: 2.0 mm 10.08 ml AXIAL RUNOUT: 2-0 mm 10.06 in)
DAMPER RUBBER INSPECTION
Rrplnoc the dampm lubb-fi || ihey ate damaged or doionoratcd.
DAMPER RUBBER
BRAKE DRUM I.D. INSPECTION
Measura the brsko drum insido diameter SERVICE LIMIT: 111 mm (44 ml
Daleol Kwir May. 1980 ©HONDA MOTOR CO.. LTD.
133
13-5
REAR WHEEL/SUSPENSION
HONDA
C70
BRAKE LINING THICKNESS INSPECTION
Mesiuie Mm brako lining thicknest-SERVICE LIMIT: 2.0 mm IQ.Qfl inl
BRAKE SHOE REPLACEMENT
Remove ihs brake arm and Indlcatoi plain.
Hi!r*i(wtf ;h« b'dko ihoe-i a"d brake cam.
BRAKE CAM
ORAKE ARM
INDICATOR PLATE
~
"
Apply gnaw to iho iiidino surface of the Brake cam. Intiall ihe brake shoei and shoe i|Hingi.
* WARNING
Contaminated brake lininia reduce stopping
ptinvr.
Keepgrtwe r>/( the liningt.
'
SHOT. SPRINGS
onAKt stiors
13-6
13fl
Dais of Ism* May, 1980 ©HONDA MOTOR CO., LTD.
"
C70
BEAR WHEEL/SUSPENSION
Install the reit seal.
Install the wear indicator plate.
NOTE
Align the indicator plan inner tab with V\e cutout pf the brake cam. ____
Install toe brake aim. NOTE
Align ihi; punch marks.
TightH!« the brake arm bolt and nut.
punch marks
INDICATOR PLATE BRAKE ARM
INSTALLATION
Innali the rear wheel.
Insert toe tsar axle and Install the axle nui,
Instill the brake torque link end secure it with a new* cotter pin.
TORQUE: 1.0-2.0 kg-m 17-14 1Mb)
Connect toe rear brake rod to the mar brake arm and inMiill the brake adjusting nui.
Loosen the sleeve nut and adjust drive chain slack (page 3-11). Tighten the tieeve nut.
TORQUE: 4.0-5.0 kg-m 129-36 li-lbl
Tighten (he axle nut and Install a new cotter ptti.
TORQUE: 4.0-6.0 kg-m 129-36 ft-lbl
Tighten the drive chain adjusting nuts,
Adjust the rear brake I page 3-14).
DRIVEN FLANGE
REMOVAL
Remove the reai wheel {page I3-3I.
Rnmnvn thu lelt Wie ecww, drive sprocket cover. upper and lower rlnvo chain muts.
BRAKE ROD
AXLE NUT
N^
BRAKE TORQUE LINK COTTER PIN
LEFT SIDE COVER UPPER CHAIN CASE
DKIVE SPROCKET COVER LOWER CHAIN CASE
Date of Issue: May. 1980 ©HONDA MOTOR CO,. LTD.
135
13-7
REAR WHEEL/SUSPENSION
C70
¦, '->>£¦'
Remove the drive chain.
Remov? the sleeve nui ami driven iso-vp.
DRIVEN SPROCKET
¦ INSPECTION
Replace the sprocket t( worn, bent of damaged-
NOTE
H the driven sprocket requires roplacomflnt, inspect the drive chain and drive sprocket 3-12).
SLEEVE NUT
• REPLACEMENT
Straight.™ Iho lock plate tab* and remove the sprocket mounting bolts.
Rtmnvo tho sprocket.
Install a new jpiockot. lock plates and bom.
Tighten tho bolts and bmtrf m (0.WI1 ml
BEARING
SEAL
r
• REPLACEMENT
Remove inn %#al and bearino,
Pack ihe bea'lng with grcaie.
Diivo in the baar-ng squa»«v umll It seals tully.
Ins;all ihe seal.
INSTALLATION
Irmall ihe dnuen Hinge ana llange sleeve.
note__________________________________
Al 40 mm BEARING DRIVER PILOT. 17 mm
;._ 079463000000
SLEEVE NUT
Date of Issue: May. 19fiG
a HONDA MOTOR CO.. LTD.
137
13-9
REAR WHEEWSUSPENSION
C70
SHOCK ABSORBER
REMOVAL
Remove the uppe' and lower ihock absorber mounting nuts and bolls, and remove (he (hock abjorben.
DISASSEMBLY
Compress Ow spring iuii enough to remove the lock nut-Loosen the lock nui and remove Ihe upper mount. Disassemble the. unit,
SHOCK ABSORBER COMPRESSOR
~
LOCK NUT
SPRING FREE LENGTH INSPECTION
Measure the sprmg tree length. SERVICE LIMIT: 310.5 mm (8-30 in| Inspect the shock body tor oil leaks.
13-10
138
Oatoc* Issue: May, 1980 ©HONOA MOTOR CO.. LTD-
C70
REAP WHEEL/SUSPENSION
ASSEMBLY
Install the spring with ihc light coils at the top.
Aopiy a locking agrnt to ihe lock nul and install It Tighlnaihfl lock nut.
INSTALLATION
Tighten the shoe* abso'bor bolts and ton,
TORQUE: 2,0-3.0 kg-m (14-221Mb)
Chrck ihofh alisiirbci operation aim Insiallition
LOCK NUT 1.5-2.5 *¦)-(11-18 ft-lbl
LOWER MOUNT
--DAMPbR
STOPPER RUSini R
^^
SHOCK ABSORBER COMPRESSOR
Dale ill lw.fr; May, 1980 ©HONDA MOTOR CO., LTD.
li'J
13-11
REAR WHEEL-'SUSPENSION
C70
SWINGARM
REMOVAL
Remove Iho muffler (page 5-2).
RemovMheiear wheel (page 1331,
Remove the dnven llange (page 13-7).
Removit ttio shoe* absorbers (paoe 13-10).
Remove the *=lf locking nul and Divot bolt Remove the swingarm.
SWINGARM PIVOT NUT
SWINGARM
INSPECTION
Inspect the pivot Bushings and boh for excessive wear. Replace if necessary.
Ori« the bushings into place with a soft hammer. NOTE;
Make sure that ;"n bushings am not damaged.
Iiipecl th« chain yunto lor wear,
PIVOT BUSHINGS
°
PIVOT BOLT
INSTALLATION
Iniull the swlnrjarm and pivot bolt
Install the muffler bracket and pivot self locking nut.
TORQUE: 2.6-3.6 kB-m (18-26 1Mb)
Irtitatl tho shock absorbers (page 1311).
Install the driven flange (page 13-9).
Install tho roar wheel Ipage 13-71.
Install the mufller,
~
"
13-12
HO
Date (if Issue: May, 1980 ©HONDA MOTOR CO.. LTD.
C70
MEMO
Daieof iMue May, 19S0 ©HONDA MOTOR CO., LTD.
141
BATTERY/CHARGING SYSTEM
C70
r
LIGHTING SWITCH
IGNITION SWITCH
ECTIFIEH
BATTERY IGNITION COIL A.C. GENERATOR
14-0
142
Daw of Issue Me v. 1980 ©HONDA MOTOR CO, LTD.
C70
14JCT/CHARGING
r
SERVICE INFORMATION 14-1 CHARGING SYSTEM 14-4
TROUBLESHOOTING 14-2 A.C. GENERATOR 14-5
BATTERY 14-3 RECTIFIER 14-8
SERVICE INFORMATION
GENERAL INSTRUCTIONS
¦ Buttery fluid lave! ihoulil he chccktnl 'Hguiarly. Fill with dinllled water only.
' Quick chaise the battery only in an emergency. Slow charging It preferred. Remove the battery from the motorcycle for charging. If the battery muit be charged on the motorcycle, disconnect the battery cobles.
& WARNING
The batter? xeneram hydrogen go* hfthh run be htgfily exploitive. Do run smoke or allow flames or spark* near the bailery, especially xMe charging ii
• All charging syitnm component* can be timed on the motorcycle.
TOOLS
sp«dal
Flywheel Holder
Common Rotor Puller
07923-179O00O, U.S.A. only uwj commercially available band strap wrench
07733O0200O1 -Removing bolt, 90016-360-000
TORQUE VALUE Generator rotor /flywheel holt
5.5 - 6.5 kg-m (40 - 47 ft.lb)
SPECIFICATIONS
Battery Capacity 6V1.AH
Specific gravity 1.260 - 1.280/20'C (68JF)
Chary r,L: -,... 1.4 amoetpi maximum
A.C. generator Capaeity {headlight low beam on| 4.000 rpoi 8,000 rpm
0.8 A mi*. 23 A max,
Rectifier type Silicon diode
Daieafluue: May. 1080 ©HONDA MOTOR CO.. LTD.
143
14-1
BATTERY/CHARGING SYSTEM
C70
TROUBLESHOOTING
No power - bey turned on
1. Deed battery
— Luw fluid level
— Low specific gravity
— Charging system tailu'e
2. Disconnected Uatiuiv caP'n
3. Ms in ( jv. hurnad out
4. Faulty ignition switch
Lew power — key turned on
1. Weak battery
— Low fluid level
— Luw specie gravity
— Charging system failure
2. Loose battery connection
Low power — engine runnlr*!) |, Battery undercharged
— Low fluid level
— Dneor more dead cells
2. Charging system failure
Intermittent power
I. Loose battery connection
?. Look charging system connection
3. Loose stinting system connection
A. Louie connection or iho't circuit In Ignition lyitem
Charging system failure.
1. Loose, broken, or shorted wire or connection
2. Rectifier faulty
3. AC. generator loudy
-|A_2 1M Datoof Issue; May. 1980
©HONDA MOTOR CO., LTD.
C70
BATTERY/CHARGING SYSTEM
r
BATTERY
REMOVAL
Remove the *iflhi side cover, Disconnect the yiuuiut uibte »¦ inn Iramc Disconnect iho positive cable at me battery. Reinovn the battery Holder plate holt. Remove the battery.
GHQUUL) CABLE POSITIVE CABLE
BATTERY
HOLDER PLATE
TESTING SPECIFIC GRAVITY
Tut each cell with a hydrometer.
SPECIFIC GRAVITY:
(20"C, 6B'F>
1.360 - 1.280 Fully charged
Below 1.250 Undercharged
NOTE
• T*o battery must be recMrfled II thn specific gravity hed to pieuenl Hie cmnkihall Irom turning.
Remove the generator color bolt
FLYWHEEL HOLDER 07022-1730000 U.B.A. ONLY - USE COMMERCIALLY AVAILABLE BAND STRAP WRENCH
Romcwe ihp generator >otot.
INSTALLATION
ROTOR PULLER OH
U.S.A. ONLY, REMOVING BOLT
90015-360-000
Alton Hie «)lo< kevway with the key on iho crank-shall md inftoll (he geneiaior lolor.
GENERATOR ROTOR
14-6
148
Daieoflwue: May, 1980 CpHONOA MOTOR CO.. LTD.
"
C70
BATTERY/CHARGING SYSTEM
1 iphtcn the generator rotOf bol' TORQUE: 5.5-6.5 kg-m (40-47 ft-lbl
STATOR INSTALLATION
Insiull the siator.
Route thn generator lead? properly.
Connect tho neutral witch load
Iraiall Hie Ml ccjiikc.He cover, ilnve sprocket Dover and geanhitt pedal.
Connect Ihegenoreto' Wire coupler.
Irumtl die right crankeaw cover, fooipegi.tide Mund nnd kick «trttf pcrj.il.
Fill the crankcaie with tho recommended oil Ipsge 2-21.
Adjust the toniTJon timing (pane 3-9).
FLYWHEEL HOLDER O/B22-179O00 OH U.S.A. ONLY - COMMERCIALLY AVAILABLE BAND STRAP WRENCH
Pate o! l»ue: May, 1980 OHONOA MOTOR CO.. LTD
149
14-7
BATTERY/CHARGING SYSTEM
C70
Sh
RECTIFIER
REMOVAL
Remove The right side cover, Remove :h* recii'ler.
iuttif ie-
inspection
Cheek the rectifier lot continuity between iho terminal*. Reverse the leads and check again.
Continuity ihould exist in one direction only
Rcplocit the roctifts' it theie is coniinuiiy in both directions
n
14-8
150
OittfOllMue: May, 1980 ©HONDA MOTOR Cp.( LTD.
C70
CYLINDER.'PISTON
MEMO
Dateotlssuo May. 1980 ©HONDA MOTOR CO., LTD.
151
IGNITION SYSTEM
HONDA /Cg£\
c7o m)
BATTERV
SILICON RECTIFIER
IGNITION COIL
JOINTS
CONDENSER
A.C GENERATOR
SPARK PLUG
IGNITION COIL
SPARK PLUG
A.C. GENERATOR
IGNITION SWITCH
ENGINE STOP SWITCH
CONOENSER
ECTIFIER
BATTERY
POINTS
15-0
152
Da:eo* Issue: May. 1! ©HONDA MOTOR CO., LTD.
"
C70
15.IGNITI0N SYSTEM
SERVICE INFORMATION TROUBLESHOOTING IGNITION COIL
SERVICE INFORMATION
GENERAL INSTRUCTION
Fof spark plug information, we page 35.
15-1
16-1 15-2
CONTACT BREAKER POINTS 15-3
SPARK ADVANCER 15-4
TORQUE VALUE Spark advancei
0.9- l.2kgm(7-9ft-lb)
SPECIFICATIONS
Ca"aoa Model
r
Spark plug ND Standard U22FS IU2JFSR-L!
For cold climate below 6°C (41°F| U20FS 1U20FSR-L1
Forextended high speed riding U24F8 IU24FSR-LI
NGK Standard C7HS ICR7HSI
For mid climate below o*C(4T*F| C6H ICR6HSI
For extended high speed tiding C9H CPHHS!
Spar* otiigoap D.6-0.7 mm (0.024 - 0.028 in)
Ignition timing Aildli tb'HTDC
Full advance 30° BTDC.J3,lQ0rpm
Condenser capacity 0.22- 026 (iF
Contact breaker point gap 0.3 - 0,4 mm (0.012 -0.016 in|
TROUBLESHOOTING
Engine cranks but will not start
1. Engine slop switch OFF
2. No spark ai plug
3. Improper ignition timing
No spark ai plug
1. Engine stop switch OFF
2. Points not opening
3. Points burned, wot fouled or flirty
4. Uu primary current lo points and colls
— Loow or broken wire
- Faulty Ignition switch
5. Piuglouled
6. Faulty plug wire
7. Coil weak or inoperative
8. Faulty condensur
Engine starts but runs poorly !. Ignition primary circuit
— Points dirty or fouled
— Incorrect point gap
— Faulty ignition coil
— Faulty condenser
— Loose or bare wire
— Intermittent short circuit
2. Ignition secondary circuit
— Faulty plug
— Faulty high tension wire
3. Improper ignition timing
Timing advance Incorrect V Centrifugal advancer faulty
Date of Issue: May. 1380
SHONDA MOTOR CO.. LTD.
153
15-1
BATTERY/CHARGING SYSTEM
C70
IGNITION COIL
REMOVAL
Remove the tight and Mi lirfq covnrv
Remove iivt Iwitory and stauei relay switch.
DJ icon nod the Aire lead*.
Remove lite coil by removing ihe attaching nur
*!om itieicltside.
CONTINUITY TEST
Chert tor cominuiiy ai ihom-n.
The coll is good i' them it continuity.
• -
IGNITION COIL
ATTACHING NUT
SECONDARY: 7.8B-9.36 kSl
R * 1 Cominuiiy
PRIMARY: 1.36-1.6511
^g»y-=—¦
Q
R x 1.000
R ¦ 1
PERFORMANCE TEST
Per form the 3-po'nt *paik tost with a coll wner. SERVICE LIMIT: 6 mm 11/4 inl min.
Follow the cO'l imtot manufacturer'* Imiruc-tiont
PRIMARY ELECTRODE
6 mm 1024 in)
SPA UK
SECONDARY CI ECTRODE
15-2
154
Date of Isiw May, 1080 ©HONDA MOTOR CO., LTD.
C70
IGNITION SYSTEM
CONTACT BREAKER POINTS
REMOVAL
Remove the commi bienker point cover. DiKomirci the point win; lead. Beniovp the con tact btrakpr assembly.
Por contact licttskei points impaction, wo page 3-' NOTE
H iheoll felt i* dry. *pply one or two drops of clrun engine oil to it
CONDENSER CAPACITY TEST
"
Remove the condflnser Item the bate i
Discharge the condnroer by grounding its tntminal
aflsinst itscas'nu.
Measure tho condense) sapacity with a tester. CAPACITY: 0.22-0.26 tfF
H >i ii out ot spBcitlcat'oA replace ihn condense*.
POINT REPLACEMENT
Remove the point itttng icrew* and bolt Replace the contact point.
r-OTF
Do not for 091 to iiutall the bakolitp washers to insulate the condenser/generator terminal 'rom (jfound.
Install contact breaker assembly in the reverse o HONDA MOTOR CO.. LTD.
155
15-3
IGNITION SYSTEM
HONDA C70
SPARK ADVANCER
Fat advancer function \m4 see pSge 3-9.
Remove "*e contact point covei unit contact bieak-ei wi»im{»ly.
Check the spring for loss al tension and advancer pin for e»waive wear if the advancei (alt* to return. Replace if necessary.
ADVANCER REPLACEMENT
Retrieve the bolt by holding the spacer. Remove the advancer
-
"
PIN
Install the advancer, aligning the Uoi Willi the flywheel pin,
Insult the spacer and tighten the bolt.
TORQUE; 0.9-1.2 kg-m (7-9 ft-lbj
SUQT
15-4
10* Issue: May-IS OHQNDA MOTOR CO.. LTD.
C70
16.ELECTRIC STARTER
SERVICE INFORMATION TROUBLESHOOTING STARTER MOTOR 16-1 16-1 16-2 STARTER RELAY STARTER CLUTCH/DRIVE CHAIN 16-5 ,e-6 {
r
SERVICE INFORMATION
GENERAL INSTRUCTION
The signer motor can be removed with iho engine in the frame.
SPECIFICATIONS
ITEM Standard Service Limit
Su*tei motor Brush spring tension 400g 114.1 «| 300 g (10.6 oz)
Biuih length 12 mm (0.47 in) 4 mm (0.18 in)
Slant" clutch driven sprocket O.O. 37.900(1.4921 ml 3676 mm (1.447 ln|
e ©
BATTERY
FUSE 10 A ¦REOO^-O—RED-
GNITION SWITCH
BLACK
STARTER RELAY
I-YELLOW/FED U™* GREEN/RED
5TARTER RELAY COIL SWITCH
SWITCH
TROUBLESHOOTING
Si.i't" motor will not turn 1. Battery discharged 2- Main c biushe» with black wre, and in iho motor case.
Repair the biuifl wire il the wire is bruktm or if it is ; 10 me mote case. • terminal to motor case: No continuity Could terminal to brum: Continuity
ASSEMBLY/INSTALLATION
Assemble 1h» starter motor,
Align lhn caw notch with the brush holder pin.
Install the rear cover aligning its slot with the brush holder pm.
Insult the tuner motor by rcvirrsino. the removal procedure.
SLOT
16-4
Dauo* Issue May, li
Q HONDA MOTOR CO., ITD.
C70
ELECTRIC STARTER
STARTER RELAY
INSPECTION
DapTHM CM! ttoiie< jv/.tch txiilun with tttc ignftlOfl ON.
The coil ti notinal II ihti naile' iclay wiich dicki.
SIARIER RELAY
Connacr an olimmeic to th» tinrtai trt'av mvitr.h cable terminal!.
Connect - 6V battery lo ihe iwtich wire toads.
The witch Is normal H then-1* coniinullv.
STARTER CLUTCH DRIVE CHAIN
REMOVAL
Rwnuvu tlw A(C. (generator 'Qior ISBCiion 14|, Remove the itarter chain guide and protector. Remove Ihe ipiocket letting plain. Remove ihe map 'I'm. Remove Ihe iiailei ciwlii .ind *p*uckr;ii.
Q.
1 v. Is ^\
I "
SNAP RING CHAIN GUIDE
PnoifCTOR
\ . r
SETTING PLATE
Dawoflsiue: May, 19SO ©HONDA MOTOR CO.. LTD.
1G1
16-5
ELECTRIC STARTER
C70
STARTER CLUTCH DISASSEMBLY
Remove tf» tfwae screw* Remnvo dta nail?' clutch outer, Remove the. tollers, olungeti and spring*.
STARTER CLUTCH INSPECTION Intpcc: the >oHen lo' smooth operat-arv
ClieCk the rollers (en i>Xr;i:«iva WOO'.
Inspect ihe drlvB and driven sprockott and chain (or uxcesiivn wear a* ilamaBo.
Meaiiue mi- dnve sp-oclet O.D.
SERVICE LIMIT: 36.76 rnm (1.447 inl
STARTER CLUTCH ASSEMBLY Inttsll the sla-mr clinch ouwr. NOTE
Stake the cntl o' each screw against the groove in the dutch outer.
Install tho tprlnrji. plunqors and rollert.
INSTALLATION
Revert* ins rnmoval prncedure.
16-6
Dare nl Issue; May, 1980 ©HONDA MOTOR CO., LTD.
C70
17.SWITCHES
SERVICE INFORMATION 17-1 HANDLEBAR SWITCHES 17-3
BRAKE SWITCHES 17-2 IGNITION SWITCH 17-4
NEUTRAL SWITCH 17-2
SERVICE INFORMATION
GENERAL INSTRUCTIONS
¦ Some wires have different colured bands Bound them near the connector. Thfssc are connected to other viires which cottespond with the bend color,
• All plastic ptufji have locking tabv mat must be relewed before disconnecting, and muii w aligned when reconnecting,
• The following color codas are used throughout this section and on the wiring diagram (taction 19).
B - Blue 0 - Green LG - Light Green w - White
Bk - Black Gr - Grey O - Orange V - Yellow
Br - Brown LB - Light Blue R - Rod
¦ To isolate art electrical failure, chock the continuity of the electrical oatn through the part. A cantrnulty check ten uiually be made without removing the part from the motorcycle. Simply disconnect the wliei and connect a continuity tetter or voli-ohimmetei to Hie terminal* or connection!.
• A continuity tester Is useful when checking to find out whether or not there i'. an electrical connection between two painu. An ohmmeter is needed la measure the resistance o' a circuit, u when tfieie Is a specific coil resistance involved, or when checking 'or high resistance caused by corroded connections.
Date of hut: Mav. '960 ¦9HONOA MOTOR CO.. LTD
(¦3
17-1
SWITCHES
C70
ft
BRAKE SWITCHES
FRONT BRAKE SWITCH
Remove the headlight.
Disconnect rtre G/V arid BK leads ol eai ixiifce
twitch.
Check (ot continuity with the rear brake applied.
Broke applied; Continuity Brake not applied: No continuity Replace the switch il noccswv.
REAR BRAKE SWITCH
~-
B> LEAD
G/Y LEAD
NEUTRAL SWITCH
H\ 1,TRA| SWITCH
Remove the lell sidn enwr and engine Sprocket cover,
Check the switch tor continuity between the switch tH'nvnal Iwire removed! and ground with the transmission In neutral and with the transmission in any goat.
In neutral: Continuity In ejufi No continuity Replace the neutral switch h" necessary.
I
17-2
lfr>
Bale ill twtie: May. 1980 ©HONDA MOTOR CO., LTD.
SWITCHES
HANDLEBAR SWITCHES
The dandinhnr ctU«H switches High*. lutn signals,
horn, engine ilop. iiartui ] must be rcplacm! as an
avsomhly-
Cinuinultv Win tor Ihe components ot the
handiclinr clutter switches follow:
Remove the headlight.
Continuity should *xist bttfyiMHl *e coloi coded
v. >enon n«hchan..
HEADLIGHT HI-LO SWITCH
TURN SIGNAL SWITCH
HORN BUTTON
HEADLIGHT Hl-LOW SWITCH
HI; BtoY
MIDDLE (Nl: YtoBraW LO: V 10 W
HMdlighi Hi Low Switch
Hi Ci Lo
Hi D----- 1___ r~>L
\J ^~tj
(N) r\___
w
Lo <*s __f\
'.
Coloi code 8 V
TURN SIGNAL SWITCH
LEFT: OtoGi
OFF: No continuitv
RIGHT: LB (o Gr
Turn Signal Switch
R w t
LEFT r*____ r"i i
ij— R NO SPARK
GOOD SPARK
I
3, Test cylinder comotejtJon
LOW COMPRESSION
NORMAL COMPRESSION
f 4. Si ait ongine
ENGINE STARTS
ENGINE FIRES. BUT DOES NOT START
01 Faulty of fended plug
(2| Fouled, Burnt or pitted contact
breaker points (3) Incorrect breaker point gao (4| Faulty wkJbhwi
15) Broken o> shorted Ngh tension wire
16) Open or shorted ignition coil {7) Faulty igniilon twich
(8) Incorrect ignition lining
Ml Engine «tpl cinnked
(2) No valve clearance
13) Valvo nuck open
(4} Worn cylinder JJi pinon rings
(5) Blown cylinder hirai gasket
(6f Flaw In cylinder head
(71 Incorrect valve timing
II) Choke ve've open
(2) Carbureter pilot senw open
{3) Air (poking through make manifold
(4) Incorrect ignition lining
5. Remove toa'k plug DRY PLUG
WET PLUG
III Floodedcarburetor
12) Carburetor choke excessively
dosed {3) Thiqtile valvo c*cflst(V9lv open
6. Stan engine with choke c'owd
13-2
Date of Issue: May, 1080 QHONUA UOTOR CO, l-TD.
C70
TROUBLESHOOTING
ENGINE LACKS POWER
POSSIBLE CAUSE
1. Ratio wheels off griiund & spin
WHEELS SPIN FREELY
WHEELS DO NOT SPIN FRESLY
II) Dragging brake
(21 Faulty wheel bearing
131 Overtightened drive chain
"
2. Check tire pressure NORMAL PRESSURE
3. Rapidly accelerate from low to second
INCORRECT TIRE PRESSURE
DOES NOT ACCELERATE WITH ENGINE SPEED RAISED
(1| Pontiutftd lit* (2) Faulty tto valve
(1J Slipping cluih
(2J Worn or uneven dutch lacing
ACCELERATES
J Rev up gradually
ENGINE SPEED INCREASES
5. Choc*" ignition liming CORRECT TIMING
ENGINE SPEED DOES NOT-INCREASE
INCORRECT TIMING
(1) Carburetor choke closed
12) Ciogaed air cleaner
13) Ciogaed fuel line
(d) Cogged fuel lank cap breather bole
151 Ciogaed muffler
U| Incorrect ignition timing (2) Ignition malfunction
6. Check valve clearance
CORRECT VALVE CLEARANCE
INCORRECT VALVE CLEARANCE
(It Incorrect valve clearance (21 Worn valve *al
7. Ten cylinder compression NORMAL COMPRESSION
I
8. Check carburetor for
CARBURETOR NOT CLOGGED
9, Remove spark plug
PLUG NOT FOULED OR DISCOLORED
J
LOSS OF COMPRESSION-
CARBURETOR CLOGGED-
PLUQ FOULED OR DISCOLORED
? (1) Valve stuck open
(2) Worn cylinder & piston rings
|3) Blown cylinder head goikei
(4) Incorrect valve timing
•*» (1) Caibureior jets clogged
—-(1) Fouled plug
(2) Incorrect ncn range plug
Date of Issue: May. 198C1 ©HONDA MOTOR CO., LTD.
18-3
TROUBLESHOOTING
C70
10. Oiock oil level and condition
CORRECT ENGINE OlL LEVEL
T1, Remove cylinder head cawei and check lubrication
SUFFICIENTLY LUBRICATED
OIL DIRTY OR LEVEL INCORRECT
INSUFFICIENTLY
LUBRICATED
111 Level too low or high |2| Contaminated oil
U) Clogged oil passage <2) Poor oil pump dflliwv (3) Low oil pressure
12. Check It engl»e overheat*
ENGINE DOES NOT OVERHEAT
ENGINE OVERHEATS
13. Rapidly accelerate or run at high speeds
ENGINE DOES NOT KNOCK
ENGINE KNOCKS
(1 I Excessive. carbon in combustion
chamber (2( Incorrect fuel (3| Slipping clutch |4) Mixture too lean
(1) Worn piston or cylinder
|2) Mltture too lean
(3) tneorrtret fuel
14) Excessive carbon in combustion
chamber (5) Advanced innit-on timing
POOR PERFORMANCE AT IDLE AND LOW SPEED
POSSIBLE CAUSE
1. Check ignition limine, & valve clearance
INCORRECT TIMING & CLEARANCE
41) Incorrect timing adjustment (2) Incorrect waive clearance
CORRECT TIMING & CLEARANCE
2. Chec* carboietor pilot icioy adjustment
CORRECTLY ADJUSTED
INCOHHECTLY ADJUSTED
3. Chech for ait leeks
NO AIR LEAKS
AIR LEAKS
(1) Mixture too loan (?( Mlxiure too rich
(1| Faulty carburetor daskei
(2r Carburetor not securely tightened
(3r Faulty intake pip* a«k*1
(4| Deteriorated O-ring
4. Remove spark plug test spnrk
GOOD SPARK
WEAK OR INTERMITTENT SPARK
[II Faulty or fouled plug
(21 Fouled, lougn. oi pitied break*'
point surface (31 Condenser shorted (4| Faulty ignition coil
18-4
170
Dateol Issi'e' May, 11
O HONDA MOTOR CO., LTD.
C70
TROUBLESHOOTING
POOR HIGH SPEED PERFORMANCE
1. Chuck ignition liming Si valve clearance
CORRECT TIMING & CLEARANCE
2. Disconnect fuel lube at caibureior and check for clogging
UNRESTRICTED FUEL FLOW
3. Check fuel filter, fu«| valve. & carburetor jet for cloosing
NOT CLOGGED
J
4. Replace carburetor main |ei CONDITION IMPROVED
I
G. Check valve nming CORRECT
I
6. Check valve spring tension
SPRING TENSION CORRECT
SMOKING EXHAUST
1. Run motorcycle a long distance at high saved
THIN EXHAUST EMITTED
I
2. Return throttle grip quickly
NO WHITE SMOKE EMITTED
INCORRECT TIMING & CLEARANCE
RESTRICTED FUEL FLOW
CLOGGED-
CONDITION AGGRAVATED-
INCORRECT
WORN OR BROKEN SPRING-
ILACK SMOKE EMITTED
WHITE SMOKE EMITTfD-
POSSI&LE CAUSE
(I | Incorrect timing adjustment |?) Incorrect
(1| Empty fuel lank
(2) Clogged 'gel tune
(3) Clogged fuel tank cap breather hole
11) Oomed jet
12) Clogged h»el filter
13) Clogged fuel valve
(1| Jet size too smell
(21 If condition improved with small jet:
a) Clogged air cleaner
b) Choke not opened fully
(l| Incorrect valve timing adjustment
(f) Faulty value spring
POSSIBLE CAUSE
(1) Worn cylinder & piston rings
(2) Oil level too high
(3) Phton rings incorrectly installed M) Faulty piston or cylinder
IS) Flaw* in cylinder head
(11 Worn intake valve guide nr stem (2) Deteriorated valve guide O-ring
3. flun motorcycle- a long distance at low speed
UNCOLORED EXHAUST
WHITE SMOKE EMITTED'
(IJ Worn exhaust valve guide & stem
(2) Exhaust valve guide incorrectly seated
(3) Worn exhaust valve stem mal
Date of Issue: MuV. 1980 ©HONDA MOTOR CO., LTD.
171
18-5
TROUBLESHOOTING
C70
FAULTY CLUTCH
POSSIBLE CAUSE
I. Properly adjust cluich
CLUTCH SLIPPING
(1) Weak clutch spring 42} Worn or distorted clutch plate Oi (riction Oik
DIFFICULT SHIFTING
DIFFICULT SHIFTING-
POSSIBLE CAUSE
(1| Broken ge*r ahili armsprino
(2( BinkKn shift fork
(3| Sluggish movement of shift drum <
fork (41 Broken shifting gear protttflion (5) Shift arm pawl disconnected 'rom ."it\ drum
PEDAL NOT RETURNED TO NEUTRAL
11) Broken shift return spring I?) Shilt ihelt Inrtrfortingwith cover
or
GEARS JUMPING OUT OF POSITION
(1) Bent shifting gear or worn shift 'ork
(2) Biokenoi weakened shirt drum itoppor Wing
ENGINE NOISE
POSSIBLE CAUSE
VALVE NOISE PISTON SLAP-
(1) Excessive valve clearance (?) Worn valve
(l) Wotnpnion & cylinder
(2J Excessive carhon in comhuttion
chamber (31 Worn piston pin ^connecting rod
*m»)l end
CAM CHAIN NOISE
Ml Worn camshaft bearing
121 Worn camshaft sprocket teeth
(3) Exceisively elongated drive chain
CLUTCH CHATTER-
ID Exeeislvo clearance between clutch
Dime & clutch outer (21 Woakoned clutch damper spring
NOISY DRIVE & DRIVEN GEARS
(1) Wurn or deteriorated driven gear damper
(2) Worn gear teeth
18-6
172
Date of luue. May, 1980 RHONDA MOTOR CO., LTD.
C70
TROUBLESHOOTING
MOTORCYCLE PULLS TO ONE SIDE
POSSIBLE CAUSE
DIFFICULT STEERING IN-BOTH DIRECTIONS
WHEEL WOBBLES
(11 Ovortightenad steering head top thread nut
(2) Broken steering i»ol balls
(3) Bom storing tiem
(1) Excessive play in wheel bearing
12) Brmt wheel rim
|3) Look spokes
(a) Excessive play In jwingarmpivoi
bushing (B| Frame boni (61 D'ive chain adjuster* unequally
•cffuated
MOTORCYCLE PULLS-TO ONE SIDE
FAULTY FRONT & REAR SHOCK ABSORBERS
(1} Unbalanced front & rear shock
absurber? |2) Fronts rear wheels not aligned (3) Bent Irani (o'k or swingnrm
POSSIBLE CAUSE
r
SOFT HIDE-HAflD RIDE
(1| WMkipringa
(2) Excessive load
fl) Faulty Irontfork
(2) Faulty rear shock absorber
NOISE IN SHOCK ABSOHHER
111 Faulty stopper rubber (2) Faulty rear shock: absorber
FAULTY BRAKE
INEFFECTIVE ADJUSTER
POSSIBLE CAUSE
(1) Worn brake lining, brake »*oc cam or brake cam
SQUEAKING
INEFFECTIVE BRAKE
ELONGATED DRIVE CHAIN
{1) Worn braka lining
(2) Foreign particles on brake lining
13) Hnugh brake drum sho* contacting
face (•41 Worn brake panel bushing
(11 Faulty 'ront brake cable
(2) Brake shoe partially contacted
(3) Mud or water in brake
(-1) OM or grease on brake lining (5) Worn Drake lining
POSSIBLE CAUSE
(1) incorrect adjustments
{2) Not lubricated sutticiemly enough
(3) Worn toiockets
Date of Issue: May. 1980
C HQNDA MOTOR CO.. LTD.
173
18-7
HONDA
C70
19. WI
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C70
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003
Daieof Issue: May, 1980 ©HONDA MOTOR CO.. LTD.
C70
20. '82 ADDENDUM
INTRODUCTION
T>ns addendum contains information lor tho 1982 C70. Refer to the base shop manual for service information not included in this addendum.
ALL INFORMATION, ILLUSTRATIONS, DIHEC TIONS AND SPECIFICATIONS INCLUDED IN THIS PUBLICATION ARE BASED ON THE LATEST PRODUCT INFORMATION AVAILABLE AT THE TIME OF APPROVAL FOR PRINTING. HONDA MOTOR CO., LTD. RESERVES THE RIGHT TO MAKE CHANGES AT ANY TIME WITHOUT NOTICE AND WITHOUT INCURRING ANY OBLIGATION WHATEVER.
NO PART OF THIS PUBLICATION MAY BE REPRODUCED WITHOUT WRITTEN PERMISSION.
HONDA MOTOR CO.. LTD. Seroc* Publication* Office
CONTENTS
1. GENERAL INFORMATION...........20-2
2. LU8RICATION....................20-6
3. INSPECTION AND ADJUSTMENT.....20*
4. FUEL SYSTEM.....................20-9
5. CYLINDER HEAD/VALVE..........20-11
6. CLUTCH.........................2012
7. TRANSMISSION..................20-14
8. CAM CHAIN TENSIONER...........20-14
9. FRONT WHEEL/SUSPENSION.......20-17
10. REAR WHEEL/SUSPENSION........20-17
11. BATTERY/CHARGING SYSTEM.....20-18
12. IGNITION SYSTEM................20-22
13. ELECTRIC STARTER..............20-26
14. TECHNICAL FEATURES...........20-27
15. TROUBLESHOOTING..............20-28
16. WIRING DIAGRAM................20-31
Dawoi Ijsue: Nov., 1981 ©HONDA MOTOR CO„ LTD.
179
20-1
C70
'82 ADDENDUM
TORQUE VALUES
ENGINE
Nam Q'ty Thrcocl riia. (mm) To*qui
kgm ft-tb
CamJiaft spiockci Fina drlvn sprocket Flywheel Valvi adjusting screw Oil crain boll Fuel tltWf boll 3 2 1 2 1 1 S 6 10 5 12 0.7 1 1 1.1-1.5 3.0 -3.8 0.7-1.1 2.0-2.5 0.03-0 05 5- B 8-11 22-28 6-8 15-18 0.2-0.4
FRAME
"
Item Q'ty Thread die. (mmj Torque
kgm (Mb
Topbridge vide boll Slewing lock Engine ho^gor boll Rear axle sleeve nui Rear brake torque link Rear ihock absorber Swingarm pivnl boll Front suspension pivot bolt Front shock absoiber upper bolt 2 2 2 1 2 4 1 2 2 8 e 8 16 8 10 10 8 8 2-6-3.5 0.8-1.2 20-3.0 3.5-4.6 1.8-2.5 2.5-3.5 2.6-3.5 2.0-Z5 20-2 6 18-26 6-9 15-22 23-33 11-18 18-25 18-25 15-18 15-18
TOOLS
SPEC1A.
Tool Nome Tool No. Q'iy Ret. pag?
Flywheel holder Valve adjuster Ro»r puller 07925G840O00 0/908-G 840000 07933-4300000 1 1 1 20-30 20-8 20-20
Dawot lane: Nov.. 1981 RHONDA MO I OH CO.. L HJ.
181
20-3
'82 ADDENDUM
C70
CABLE AND HARNESS ROUTING
CHOKE CABLE
MAIN HAHNESS
20-4
183
Dew of Iwue Nov., 1981 ©HONDA MOTOR CO.. LTD.
~
C70
'82 ADDENDUM
MAINTENANCE SCHEDULE
Perform the PRE-RIDE INSPECTION in the Ownm't Manual at each scheduled inalntenanct! ixttiod.
I: Inspect 8r*d Clean, Adjust. Lubricatn m Reolace if necessary.
C Clean
R: Replace
A; Adju*.
L: Lubricate
r^ WHICHEVER COMES FIRST ODOMETER READING (NOTE 31
ITEM ^""\^^ / t$ /// /ii 1 y / R?l« i„ / page
EVERY 4FS 1 g in dusty a'E«
(21 Service mom Irequenriy when riding In rain or at full throttle IUS.A. only). (3) For higher odometer reading, repeat at thn frrtQucwrv interval established here.
II
Date o-t Iftue:
©HONDA MOTOR CO,. LTD.
Nov., H
183
20-5
'82 ADDENDUM
C70
2. LUBRICATION
OIL RECOMMENDATIONS
Use HONDA 4-STROKG OIL or muimIwh. APt SERVICE CLASSIFICATION: SE or SF VISCOSITY SAE10W4O
Other viscosities shown in the chart mav be used when ihe average temperature in your rfdtng .km n within the indicated range.
1____ h,
SAE20VV-40. 20W-50
1 F
5AE10W 40
^^^^^^> ^^i
>At iun -jo
20 ' 0 20 40 (10 80 _______1____ i i i i 100° F C
— 30 -20 -10 0 10 20 30 40«>
3. INSPECTION AND ADJUSTMENT FUEL STRAINER
Turn the luel vslvq OF F
Looii«n the carburetor drain screw and drain the fuel from ihe carburetor Into * suitable carnal nor
£, WARNING
Gasoline it flammable and d explosive under certain conditions. Do not smoke or allow fames or sparks near the equipment while draining fuel.
Remove the fuel fitter boh and pull out (he fuel filler and 0 rings.
Wash the fuel filter In clean non-flammable or high flash point solvent.
Reinstall the fuel hilar and new 0 i""9' '"'o the fuel waive Hand tighten the fuel filter Doll making sure the new O-nngs ate In place. Then lorc|»Ht to specification:
TORQUE: 0.3-0.5 kflm (2-4 ft-lb)
After Installing, turn the fuel valve ON check (hi: air deaner case.
Connnct me breather tube.
ELEMENT
Date of Issue: Nov.. 1981 ©HONDA MOTOR CO.. LTD.
20-7
'82 ADDENDUM
VALVt CLEARANCE
TIMING MARK HOLE CAP
INDEX MARK
NOTES:
• Inspect and adjust valve clearance ivhlla the engine is cold Ibetow 36°C. 95°F).
• Now D'e location of the "T" mark
To check Die valve clearance, remove the crankshaft, timing marfc hole and valve mipee-tion raps.
Adjust clearance H necessary using valve adjuster D7908GB4O00O (we page 3-61.
B« iuM to relndall the caps.
IGNITION TIMING
NOTE: The Capacitive Discharge Ignition iyi tern ii lactoiy pre-set and cannot be adjusted. To impnci thn function nf the CDI rompo rents. ignition timing inspection procedures aie fl|w*n here
3cmovo the timing hole cap.
Connect a tnchomctnr and timing lifiht
Start the engine ana allow it to >dio 11,500 'p">l. <^eck the ignition timing.
Timing is correct if tne index mark aligns with the "F" mark at idle,
II the ignition timing is incorrect, check the CDI un't. exOier coil end pulse generator, and replace faulty parts. Refer to pa$e 20-22. Ignition System.
BATTERY
RemovP the right aide caver. Inspect the battery fluid) level
When the fluid nean tlie lower level, loosen the Doll end open iht? baitcrv oracKM for access to the battery. Remove the bat wry filler caps
Carefully add distilled water to the upper level mark using a small syringe or plasi.c funnel.
NOTE Add only distilled water. Tap water will shorten the service lite ul the battery.
The battery electrolyte contains sulfuric acid. Protect your eyes. skin. and clothing.
In caie o! contact, flush thoroughly with water arid contact a doctor If electrolyte gets In your eyes.
CRANKSHAFT CAP
TIMING LIGHT
FILLER CAPS UPPER LEVEL
LOWER LEVEL BRACKET
liOLI
20-8
186
Data of (Hue: Nov., 1981 ©HONDA MOTOR CO.. LTD.
C70
82 ADDENDUM
Replace Vie battery if sulfation or sediment* havtt scDinuilutifil tin Hit* bottom.
CAUTION: When checking iha bamrv (rise trolyto level or odciimi distilled water, nuke sure the breather tuba is connwtitd lo the battery breather outlet elbow as shown.
CAUTION
BAH. ELBOW
BATTERY 8REATHER BE
INSERT THE BATT. BREATHER TUBE SECURELY ON THE BATTERY ELBOW.
<". n i i. ~i
m *
•
4. FUEL SYSTEM
SPECIFICATIONS
Cfl'b identification no. PB15A
Main jet Below 1,6O0m (6,000 It) • 75 Above 2.000 m 16.500 ft 1 • 73
Throttle vaiva a 3 0
Jet needle OAA
0,03-0.05 kg-m 10.2-0.4 ft-lb)
Datt of Issue: Now.. 1981
IS HONDA MOTOR CO., LTD,
187
20-9
'82 ADDENDUM
C70
*
HIGH ALTITUDE
MAIN JLI
When tne vehicle n to bo oporawd contlnu-outlv *>ove 2,000 meteis 16500 Inctl the carburetor must be adjuttcd jo Improve drive-abllltv a*»J decrease exhausi emissions
1. Remove the carburirtor.
2. Remove the carburetor float chamber.
3. Remove die * 75 mam |et and install the * 72 main jet
4 Reassemble and install Die carburetor
& Warm up thrf engine lo operating tempera-lure. {.Stop and go driving lor ten minutes is sufficient.)
6 Adjust the Idle speed to 1,500.*. 100 ipm v/llh thii throttle Stop screw.
NOTE: Trin Adjustment mun be made at hinh altitude to ensure proper high altitude operation,
7 Attach the Vcnic»e Emission Control Information Updai" label attfimvn,
NOTE: Du nol attach mo label to any p*n ihat can be easily removed from the vehicle.
^WARNING
Continuous operation at an altitude lower then 5,000 feel 11.500 meters) wish the carburetor artjuiicd for high altitudes may cause the engine to Idle roughly and staff and could cflUW engine damage horn overheating. When the vehicle is 10 be operated continuously below 5.000 feel 11.500 meters), reinstall the * 75 main jet and ad|ust the idle spaed to 1,5001100 rpm.
8e sure to ma kit these adjustment at low olf ¦-tude.
Vtmaf iHtSsioii conrno, .vtGftMnro* jFiwii 10*0* MDIORCP. ItO /~
IMS VEMCU HAS BeDH ADJUSttO 10 f -1
iiimovc mtssxm ccNtnoi wuamtxa V
'••".'• !'¦'¦•¦¦¦ '¦ III. i .' lTllf=
«IflUO£ PERKHtUAKf »D,IUSIvl{M r*SIMUCl«KS Afl MHAIllf M tout* *UI«.0«.t£'L> K)»H* DBUIfl
20-10
ISO
Date of Issue: Nov.. 1981
OJ) HONDA MOTOR CO., LTD.
C70
'82 ADDENDUM
5. CYLINDER HEAD/VALVE
SPECIFICATIONS
STANDARD SERVICE LIMIT
Camihuh Cam heigh! IN. EX. 27.945 mm(1.1002 itl| 37.56 mm 11.084 6 (nl
76.076 mm (1.0266 in) 20 69 mm (1.0114 ir,|
CYLINDER REMOVAL Remove die ft HEAD Drit Cover. INDEX MARK "O" MARK \ fc M J —
Disconnect tho intake pipe from Die cylinder head.
Remove the mu"w and lhi> spark plug cap
Rarnovo the cyhndet head left side covet
Remove ihe crankshaft cap and lurn the crankshaft countaickickwiw to al>on tho "O" mark on The camshaft lorocfcel with the mde« mark.
Remove Ihe camshaft spiockeL Remove iho cylinder head |page6-4).
INSTALLATION
Iniia'l the cylindw head assembly (page 6-13)
Remove tho cam chsln tetubnei push tod tpaqtt 20-14 J,
Turn ihe crankshaft counterclockwise and align th« "T" mark with die index mart,
Piase the cam chain over tho camshaft sprocket. allnning the sprocket "O" mark with the cylinder ttaad Index mark.
Install the camshaft sprocket on We camshaft and lighten the sprocket bolti.
TORQUE: 0.7-1.1 kfl-m |5-8ft-ibJ
Install the remaining removed parts (page 6-141.
CAMSHAFT SPftCjCKCT
INDEX MARK
T™ MARK
Daw of Issuo: Nov.. 1981 ©HONDA M0TQR CO., LTD.
20-11
'82 ADDENDUM
C70
6. CLUTCH
SPECIFICATION
ITEM STANDARD SERVICE LIMIT
CluKh spring I'M length 19.1 mm 10.75 in| 17.5 mm (0.69 In)
20-12
190
Oate of Issue: Now.. 1981 ©HONDA MOTOR CO.. LTD,
C70
'82 ADDENDUM
NOTE: For disassembly and inspection see 3*3.
CLUTCH WEIGHT
ASSEMBLY
install the dutch weights on me clutch drive plate as shown
Install ill.- &iap 'lug and the clutch springs.
DRIVE PLATE
STOP RING
CLUTCH OUTER
Install the drive plate in the dutch outirr and tighten thit screws in 2-3 steps In a crisscross pattern.
Initall die clutch damper springs
SCREW
PAMPER SPRING
Install the drive gear ourar and clutch center
NOTE: Alrtjn the grooves in the clutch with the bosses on the drive
DRIVE GEAR
CLUTCH CENTE1
Initall the clutch plates and discs and secure with thesm ring.
Align
Date ol issue: Nov., 1981 ©¦HONDA MOTOR CO.. LTD.
191
20-13
'82 ADDENDUM
C70
7. TRANSMISSION
SPECIFICATIONS
ITEM ST ANOARD SERVICE LIMIT
Shift fork LO- 34.075-34.100 mm 11.3415-1.3425 in) 34.14 mm (1.344 inj
8. CAM CHAIN TENSIONER
SPECIFICATIONS
ITEM STANDARD LIMP I
Sl>'i'"j lis? Ifl-gih S3 mm (3.3 ml TTmm 0.0 ,.0
PuiKiodO.D. 11385-13.000 mm (0.4718 0«;24 in) 11.9* mm (0.470 IM
PUSH ROD
REMOVAL
Dram the erigheoil.
Remove the waling bolt, waiter, tora-onei Spring and post tod.
Remove the 6 mm boll and sealing tv«hor.
6 mm BOLT
SEALING BOLT
INSPECTION
Chock Uio puih rod (or wear or damage, and measure trie O.D.
STANDARD: 11.985-12.000 mm
(0.4718-04724 inl SERVICE LHVIT: 11.94 mm (0.470 lr>)
Mcmuro the spring free length.
STANDARD: 83 mm 13.3 in|
SERVICE LIMIT: 77mml3.0inl
Replace eiihei pott il its meaviromor" not full within the limit
PUSH non
TENSIONER SPRING
20-14
19?
Dateoflwue Nov., 1981 &HONOA MOTOR CO,, LTD.
C70
'82 ADDENDUM
TENSIONER
CRANKSHAFTCOVER
""
r
REMOVAL
Remove the tensloner push rod (page 20-1*>-
Reroove Iho A.C. generator and flywheel long* 20-1 B|.
Remove the starter chain and sprockets Iptgo 165).
Remove the crankshaft cover and iho cam chain tomiorter.
Check the tenuQner sprocket lor wear or damage.
O-RING
TENS10NER/PUSH ROD
INSTALLATION
Install me cam chain tonsioner.
Install tha O-ring* on Iho ciankshalt cover ^^ screw holes and cover.
Install ihe crankshaft cover and bghten it with two Krewi.
O-RING BOLT CAM CHAIN ItNSIUNtK
O-RING
CRANKSHAFT COVER
Install the starter chain and sprockets-
Install Ute flywheel end AX. generator (page 20191.
~
Daw of Issue: Nov., 1981 ©HONDA MOTOR CO.. LTD.
SNAP RING
CHAIN GUIDE
PROTECTOR
SETTING PLATE
193
20-15
'82 ADDENDUM
C70
I rural I ttio puih rod. spring, wainet ami seating boll.
NOTE; Make wire the push rod vjJuo is free darn duit before imtitl laiion.
PUSH ROD
SPRING
PUSH ROD VALVE
WASHER SEALING BOLI
Torque the »eali»B boll
TORQUE: 2,0-2.6 Kfl-inOfr 18 f!-W
Fill the crankcaw with the recommended oil (pane 204J.
Pour clean engine oil through ilic 6 mm boll hole until oil flows out nl the nolo.
Iniiall the 6 . 18 mm Imlt and wal.rtg lyncher.
NOTE; U* the prooe' length hull A Jonoer bolt may interfere with the push rod.
SEALING BOLT
20-16
Daw of Issue; Nov.. 1981
© HONDA MOTOR CO.. LTD-
C70
'82 ADDENDUM
9. FRONT WHEEL/SUSPENSIOH
6.0-90 kg m (43-65 H-lbl
20-3.0 kgrr 04-22 ft.|b)
2.5-3.6 kg-118-25 ft-lbj
2.0-Z5ks-m 114-16 ft-tb)
NOTE: Remove the choke cable bracket and diiconnect th« able from the choke lever to remove the left handlebar twitch.
\ ^2,0-Z5kfttn \ M4-18fM&,
SPRING FREE LENGTH; l?3.i»mm(6.a3.n, SERVICE LIMIT: 170.0 mm (6.69 in]
3.0-4.0 kg-m 122-29 l: I b i
10. REAR WHEEL/SUSPENSION
^
SPECIFICATIONS
ITEM STANDARD SERVICE LIMIT
Shock absorber spring fre« lenoin ------------------------------------------------ 229.1 mm (9.02 in) 224.5 mm (8.84 jnl
DBWollBue: Nov.. 1981 ©HONDA MOTOR CO., LTD.
20-17
'82 ADDENDUM
C70
11. BATTERY /CHARGING SYSTEM
SPECIFICATIONS
Battery Capacity 12V 5AH
Specific gravity 1.270-1 290/20°C I68°F|
piarglng raw 1.4 amperes maximum
HEADLIGHT SWITCH
BATTERY
20-18
Date of Issue: Nov., 1981 ©HONDA MOTOR CO., LTD.
-C2\
C70
'82 ADDENDUM
r
AX. GENERATOR
INSPECTION
Remove the from cover-
Disconnect tho A.C. guneraior coupler
Measure (he rnistaiice between the terminal!
RESISTANCE:
Whin-Grnn: 0 3 0.6 Otirm Yellow-Green: 0.2-0.6 Ohms
e the stAtoi asietnbiv H e.tner once .i, not within range.
AX. GENERATOR COUPLER
REMOVAL
Remove the Iront covet
Rgmove ihe gearshift Dedal and tho drive intockut cower
DRIVE SPROCKET COVER
GEARSHIFT PEDAL
LEFTCRANKCASE COVER
NEUTRAL SWITCH
Disconnect tho A.C. generator coupler.
Disconnect the neutral switch load 'torn the switch tormina! ant] remove the left crank-caw
Remove tho wire protector.
WIRE PROTECTOR WIRE LEAD
DaW of Issue: Nov.. 1981 ©HONDA MOTOR CO.. LTD.
197
20-19
'82 ADDENDUM
C70
STATOH SCREWS
Remove two ilaiui »tiewi and tutor from the loft cranhcair cover.
LEFT CRANKCASE COVER
U» iho f Jyivfeel holder or a band Mrap holder and secure thu flvwnwl lo p "OFF"
2. Poorly connected, broken or tfuxtaq wire*
- Between AC generator and ignition coil
- Between CDI unit and engine nooswiich
- Between CDI unit and ignition coil
- 8etween ignition coil and plug
- Between pulse generator and CDI unit
3, Faulty ignition coil
4, Foully CDI unrt
6. ACgci-Mator (Butty 8. Faulty pulse generator
Engine Slant bui Rum Poorly
1. IgnitiiKi primary ci'C.i't
- Fau'ty Ignition coll
- Lome or bar* wire
- Faulty pulie generator
2. Secondary circuit
- AC geneiator faulty
- CDI unit 'auliv
- Faulty pulw generator
- Faulty spark advancer
IGNITION COIL
Rl-MQVAL Remove the battery. Rifinove rhe battery box
BATTERY BOX
DatootlsB*: Nov,, 1981 ©HONDA MOTOR CO.. LTD.
201
20-23
'82 ADDENDUM
Remove the (art title cover.
Remove the relay box aitachinQ nut and bolt.
Remove the relay box
Remove the Ignition coll motirung nut and remove the Ignition coif
INSPECTION
Measure the reti&ianca of the primary v>a secondary coll.
PRIMARY: 0.2-0.3 Ohm
SECONDARY: 3.4-4.2 K ohm
Replace etner coil if m rei'Stinco does not uii w%nw ift* nm,
CDI UNIT
REMOVAL
Remove the battery and bailey ho>
Remove the CDI unit.
20-24
Date of Isme: Nov.. 1981 ©HONDA M3T0H CO,. LTD.
C70
'82 ADDENDUM
INSPECTION
Chock the continuity of the GDI unit Intuit-
IGN
EXT
SW
Replace the CDI unit if the readings ate not within tho limit* ilinwn in the tabic.
NOTES:
• ThB CDI unit ii Hillv iramiitoriirt,
• For accurate testing, il u neceisaty to use a «>ecif»Q 'also readings.
¦ Use a SANWA ELECTRIC TESTER IP/N 07308-0020000} o> KOWA ELECTRIC TESTER (TH-5H).
r
~-^_^ • PioOa - Probe —-~_^^ SW EXT PC ----------------- E ----------------- IGN
SW "^-^^ oo oo oo oo
EXT 0.1-20 ^^^ oo oo OO
PC 40-100 20-800 10-500 oo
E 1-50 O.t-20 30-500 oo
IGN CO oo oo oo
Range:
SANWA: -Kohim
KOWA; x 100 Ohms
EXCITER COIL/PULSE GENERATOR
INSPECTION
H emote I he f ton I covet.
Disconnect the A.C. gcneiauit wue coupon
Measure the exciter coil resistance oeiween the btack-'red y/ite terminal and the ground.
EXCITER COIL RESISTANCE: 150-700 Ohm
Muasuir thr- pulse gencrato* coil resistance between me biue/wh.tc and the green wire terminals.
PULSE GENERATOR RESISTANCE: 60-170 0h«
A.C. GENERATOR COUPLER
Date of Issue: Nov., 1981 RHONDA MOTOR CO., LTD.
?C.l
20-25
82 ADDENDUM
HONDA
C70
13. ELECTRIC STARTER STARTER MOTOR
REMOVAL
Remove die starter drive sprocket snap ring (page IBS).
Disconnect the starter able at ihti motor terminal.
Remove trie starter motor mounting bolts and rcmOtfO the motO',
STARTtR MOTOR
fARTfcRCABLE
_ 26 2aa oma1 laue: Nov-l9ei
l in the oil chamber. The amount of oil present is doterm'ned by a combined action of the valva and the tensioner tonno.
When thn tensioner spring pushes the tod up to remove chain sleek, the oneway valve opens and allow* oil cullected in the rod to flow into the oil chamber.
When excess tension stuns to move the push rod down, pressure from the oil in iho chamber forcei the valve closed so tho position o' tho rod is maintained.
TENSIONER^ ROLLER
TENSIONER ARM
CAM CHAIN
PUSH ROD
ONEWAY VALVE
OILCHAMBER
6 mm BOLT
* TENSIONER SPRING
SEALING BOLT
Date of Issue: Nov., 1981
© HONOA MOTOR CO.. LTD.
205
20-27
'82 ADDENDUM
C70
/
15. TROUBLESHOOTING
ENGINE DOES NOT START OR IS HARD TO START
I. Chock if ftifil H gutting to carburetor
GETTING TO CARBURETOR
2. Try spark test GOOD SPARK
3. Tbh cylinder compression COMPRESSION NORMAL
t, Start by following normal Msrtir procedure
ENGINE DOES NOT FIRE
5. Romove ip.n* plug DRY
I
6. SUM with choke applied
NOT GETTING TO CARBURETOR
WEAK OR NO SPARK-
LOW COMPRESSION
ENGINE FIRES BUT-SOON STOPS
WET PLUG
Probable Cause
{1} Mo futl in fuel ta->k
(2! Clogged Kiel tube or fuel filler
(3) Cloggsd lloat valve
(4) Clogged fuel lank rap tveother lube
111 Faulty spark plug
(21 Fouled spark plug
131 FaulivCOIumi
|4| Brokvn or snorted high tension
wire 161 Faulty AC gonoraio-161 Broken or shorted ignition coil (7) Faulty pulse generator 181 Poorly connected, broken nr
shorted wires
ID Faultv recoil starts'
(?) Valve clearance too small
(3) Valve stuck open
(4) Worn cylinder and piston ringi
(5) Damaged cvlindHr headgaikBi
(6) Seized valve
(7) Improper valve riming
01 Choke excessively open
(2( Carburetor pilot soew excess
i we I y closed (31 Ave carbon bui duo In combustion chamber
(2) Use ol improper Quality of fuel
(3) Clutch slipping
(4) Fuel-air mixture too lean
of Issue: Nov.. 1981 HONDA MOTOR CO., LTD.
zu'/
20-29
'82 ADDENDUM
C70
13. Accelerate 01 run at nigh speed ENGINE DOES NOT KNOCK
ENGINE KNOCKS
POOR PERFORMANCE AT LOW AND IDLE SPEED
ID Worn piston and cylinder 42) Fuel-si' mixture too lean (3) Use of improper grade of luol (4 J Excessive carbon build-up In
combustum chamber (5f Ignition timing loo advanced
(Faulty CDl unit or advancer)
1. Check ignition timing and valve clearance
CORRECT
t 2 Chock carburetor pilot screw adjustment
connccT
3. Check ilat' ii leaking past carburetor iniulatat
NOT LEAKING
4 Try spark test
GOOD SPARK
INCOHHECT-
INCORRECT-
LCAKING
WEAK OR INTERMITTENT-SPARK
Probablo Cause
(11 Improper valve clearance 121 Improper ignition timing {Faulty CDI unit or spa'k advancer]
(1) Fuel-air mixture too lean
(2) Fuel-air mixture too'Ich
(t) Deteriorated insulator 0 ring (2) Loose carburetor
(11 Faulty, carbon or wet fouled
tpsrk plug |2I Faulty COI unit I3I AC generator faulty |4| Faulty Ignition coll |5) Faulty pulse advance'
POOR PERFORMANCE AT HIGH SPEEDS
1. Check ignition timing and valvD clearance
CORRECT
I
2. Disconnect fuel tube at carburetor
FUEL FLOWS FREELY
3. Remove carburetor and check for clogged jet
NOT CLOGGED
4. Check valve timing CORRECT
B. Check valve spring tension NOT WEAKENED
INCORRECT-
FUEL FLOW RESTRICTED
CLOGGEO
INCORRECT
WEAK
Probable Cause
-*- (I) Impropervaivedeaiance
(2) Faulty COI unit
(31 Faulty pulse generator
(4| Faulty advancer
¦*- (1| Lack of fuel in tank
(21 Clogged fuel line
13) Clogged fuel tank breather tubo
M) Clogged Itiel valve
* 0) Clean
(1! Cam sprocket rx>t installed proDClv
*- 111 Faulty spring
20-30
208
Date of Issue: Nov.. 1981 ©HONDA MOTOR CO.. LTD-
C70
'82 ADDENDUM
16. WIRING DIAGRAM
<~
r
r
o o
to CD
N
¦ 9
¦¦: 4
is!
? 9
" 6 6
s :: i
¦ g
! 5
1 I
£ ??
3 9 [g
s J 66
3 z i
¦ 9
i 9 A
a <5
" - -¦
i ?
A s i
IS ¦- 9
5 g a 6
I 6 s
Date of Issue: Nov., 1981 ©HONDA MOTOR CO., LTD.
209
20-31