Page 24 of 288

CHAPTER 4
ENGINE
CARBURETOR
......................................... 4-1
CYLINDER HEAD
..................................... 4-8
CAMSHAFT AND ROCKER ARMS
....... 4-13
VALVES AND VALVE SPRINGS
........... 4-16
CYLINDER AND PISTON
....................... 4-21
CLUTCH
.................................................. 4-27
KICK AXLE
............................................. 4-33
SHIFT SHAFT
......................................... 4-34
OIL PUMP
............................................... 4-36
CDI MAGNETO
....................................... 4-39
CRANKCASE AND CRANKSHAFT
....... 4-41
SHIFT FORK, SHIFT CAM AND
TRANSMISSION
..................................... 4-44
CHAPTER 5
CHASSIS
FRONT WHEEL AND REAR WHEEL
...... 5-1
FRONT FORK
........................................... 5-6
HANDLEBAR
............................................ 5-9
STEERING
.............................................. 5-10
SWINGARM
............................................ 5-11
CHAPTER 6
ELECTRICAL
ELECTRICAL COMPONENTS AND
WIRING DIAGRAM
................................... 6-1
IGNITION SYSTEM
................................... 6-2
CARBURETOR HEATING SYSTEM
........ 6-6
MAINTENANCE RECORD
....................... 6-9
Page 37 of 288

GEN
INFO
1 - 7
SPECIAL TOOLS
YM-1312-A, 90890-01312Fuel level gauge
This gauge is used to measure the fuel level in the
float chamber.YM-1312-A 90890-01312
YM-01326, 90890-01326 T-handle
This tool is used for holding the damper rod holder
when removing or installing the damper rod holder.YM-01326 90890-01326
90890-01186 Fork seal driver attachment
This tool is used to installing the oil seal.90890-01186
YM-8035, 90890-01311 Valve adjusting tool
This tool is necessary for adjusting valve clearance.YM-8035 90890-01311
YM-33963, 90890-01184 Fork seal driver weight
This tool is used to installing the oil seal.YM-33963 90890-01184
YM-34487
90890-06754Dynamic spark tester
Ignition checker
This instrument is necessary for checking the ignition
system components.YM-34487 90890-06754
YM-33975, 90890-01403 Ring nut wrench
This tool is used when tighten the steering ring nut to
specification.YM-33975 90890-01403
YM-91042, 90890-04086 Clutch holding tool
This tool is used to hold the clutch when removing or
installing the clutch boss securing nut.YM-91042 90890-04086
YS-1880-A, 90890-01701 Sheave holder
This tool is used for when loosening or tightening the
flywheel magneto securing nut.YS-1880-A 90890-01701
Part number Tool name/How to use Illustration
Page 58 of 288
SPEC
2 - 3
Brake:
Front brake type Drum brake
Operation Right hand operation
Rear brake type Drum brake
Operation Right foot operation
Suspension:
Front suspension Telescopic fork
Rear suspension Swingarm (monocross suspension)
Shock absorber:
Front shock absorber Coil spring/oil damper
Rear shock absorber Coil spring/gas, oil damper
Wheel travel:
Front wheel travel 110 mm (4.33 in)
Rear wheel travel 93 mm (3.66 in)
Electrical:
Ignition system CDI magneto
GENERAL SPECIFICATIONS
Page 66 of 288

SPEC
2 - 11
CHASSIS
Item Standard Limit
Steering system:
Steering bearing type Angular bearing ----
Front suspension:
Front fork travel 110 mm (4.33 in) ----
Fork spring free length 425.1 mm (16.74 in) 417 mm (16.4 in)
Fork spring fitting length 415.1 mm (16.34 in) ----
Spring rate, STD K = 3.4 N/mm
(0.35 kg/mm, 19.41 lb/in)----
Optional spring/spacer No ----
Oil capacity 64 cm
3
(2.26 lmp oz, 2.16 US oz) ----
Oil level 185 mm (7.28 in) ----
Oil grade Fork oil 15W or equivalent ----
Rear suspension:
Shock absorber travel 48 mm (1.89 in) ----
Spring free length 169 mm (6.65 in) ----
Fitting length 165 mm (6.5 in) ----
Spring rate, STD K = 45.6 N/mm
(4.65 kg/mm, 260 lb/in)----
Optional spring No ----
Enclosed gas pressure 2,000 kPa
(20 kg/cm
2
, 290 psi)----
Swingarm:
Swingarm free play limit
End ---- 1.0 mm (0.04 in)
Side clearance ---- 0.3 mm (0.01 in)
Wheel:
Front wheel type Spoke wheel ----
Rear wheel type Spoke wheel ----
Front rim size/material 14
´
1.40/steel ----
Rear rim size/material 12
´
1.60/steel ----
Rim runout limit:
Radial ---- 2.0 mm (0.08 in)
Lateral ---- 2.0 mm (0.08 in)
Drive chain:
Type/manufacturer DID420(I)/DAIDO ----
Number of links 86 links ----
Chain slack 40 ~ 53 mm (1.6 ~ 2.1 in) ----
Chain length (10 links) ---- 121.9 mm
(4.80 in)
MAINTENANCE SPECIFICATIONS
Page 109 of 288

3 - 2
INSP
ADJ
PRE-OPERATION INSPECTION AND MAINTENANCE
*: Since these items requires special tools data and technical skills, they should be serviced.
*
1
: For USA
SERVICE NOTES:
No. 1. DRIVE CHAIN: In addition to tension and alignment, chain must be lubricated every
0.5 ~ 1.0 hour. If unit is subjected to extremely hard usage and wet weather riding, chain
must be checked constantly. See “Lubrication Intervals” for additional details.
No. 2. AIR FILTER: Remove and clean filter every 20 ~ 40 hours.
PRE-OPERATION INSPECTION AND MAINTENANCE
Before riding for break-in operation, practice or a race, make sure the machine is in good operating
condition.
Before using this machine, check the following points.
GENERAL INSPECTION AND MAINTENANCE
* Chassis fastenersMake sure that all nuts, bolts and screws are
properly tightened.
Tighten if necessary.
SidestandCheck operation.
Lubricate and repair if necessary.
* Spark arrester
*
1
Clean.
* Front forkCheck operation and for oil leakage.
Correct accordingly.
*Rear shock
absorber assemblyCheck operation and shock absorber for oil
leakage.
Replace shock absorber assembly if necessary.
Item Routine Page
Brake Check operation/adjustment. P3-11
Engine oil Change oil as required. P3-5 ~ 7
Drive chain Check alignment/adjustment/lubrication. P3-12
Spark plug Check color/condition. P3-19
Throttle Check for proper throttle cable operation. P3-3
Air filter Foam type – must be clean and damp oil always P3-3 ~ 4
Wheels and tires Check pressure/runout/spoke tightness/bead stopper/axle nuts. P3-15 ~ 17
Fittings/fasteners Check all – tighten as necessary. P2-13Dealer
NoteItem Checks and maintenance jobsInitial Every
10 hours
(1 month)60 hours
(6 months)120 hours
(12 months)
3
Page 134 of 288
3 - 13
INSP
ADJFRONT FORK INSPECTION/REAR SHOCK ABSORBER INSPECTION/
REAR SHOCK ABSORBER SPRING PRELOAD ADJUSTMENT
lTighten the wheel axle nut while pushing
down the drive chain.
T R..
Axle nut:
60 Nm (6.0 m • kg, 43 ft • lb)
EC36C000
FRONT FORK INSPECTION
1. Inspect:
lFront fork smooth action
Operate the front brake and stroke the
front fork.
Unsmooth action/oil leakage ® Repair
or replace.
EC36K000
REAR SHOCK ABSORBER INSPECTION
1. Inspect:
lSwingarm smooth action
Abnormal noise/unsmooth action ®
Grease the pivoting points or repair the
pivoting points.
Damage/oil leakage ® Replace.
REAR SHOCK ABSORBER SPRING
PRELOAD ADJUSTMENT
1. Elevate the rear wheel by placing the
suitable stand under the engine.
2. Remove:
lRear shock absorber
Refer to “SWINGARM” section in the
CHAPTER 5.
3. Remove:
lSpring guide 1
NOTE:
While compressing the spring, remove the
spring guide.
Page 252 of 288
5 - 7
CHAS
FRONT FORK
EC558000
FRONT FORK DISASSEMBLY
Extent of removal:
1
Oil seal removal
2
Damper rod removal
Extent of removal Order Part name Q’ty Remarks
FRONT FORK DISASSEMBLY
Preparation for disas-
semblyDrain the fork oil.
1
Adjuster 1
2
Fork spring 1
3
Dust cover 1
4
Stopper ring 1
5
Bolt (damper rod) 1 Use special tool.
Refer to “REMOVAL POINTS”.
6
Inner tube 1
7
Damper rod 1
8
Oil seal 1
9
Outer tube 1
1
2
Page 254 of 288
5 - 8
CHAS
FRONT FORK
REMOVAL POINTS
Inner tube
1. Remove:
l
Bolt (damper rod)
NOTE:
While holding the damper rod with the damper
rod holder
1
and T-handle
2
, loosen the bolt
(damper rod).
Damper rod holder:
YM-1300/90890-01294
T-handle:
YM-01326/90890-01326
EC555000
ASSEMBLY AND INSTALLATION
Front fork assembly
1. Install:
l
Oil seal
1
NOTE:
Press the oil seal into the outer tube with fork
seal driver weight
2
and fork seal driver
attachment
3
.
2. Fill:
l
Fork oil
3. After filling up, slowly pump the fork up
and down to distribute the fork oil.
Fork seal driver weight:
YM-33963/90890-01184
Fork seal driver attachment:
90890-01186
Oil quantity:
64 cm
3
(2.26 Imp oz, 2.16 US oz)
Recommended oil:
Fork oil 15W or equivalent