SPECGENERAL SPECIFICATIONS
2-2
Item Standard Limit
Spark plug
Manufacturer/model NGK/DPR8EA-9 or NGK/DPR9EA-9
Gap 0.8–0.9 mm •••
Clutch typeWet. Multiple-disc
Transmission
Primary reduction system Spur gear
Primary reduction ratio 71/34 (2.088)
Secondary reduction system Chain drive
Secondary reduction ratio 47/15 (3.133)
Number of drive chain sprocket
teeth (front/rear) 15/47
Transmission type Constant mesh 5-speed
Operation Left foot
Gear ratio 1
st2.583
2nd1.588
3rd1.200
4th0.955
5th0.792
Chassis
Frame type Open cradle backbone frame/detachable
rear frame
Caster angle 27° •••
Trail 117 mm •••
Tires
Front:
Type With tube
Size 90/90-21-(54R) / 90/90-21-(54S)
Manufacturer/model Pirelli / MT70 - Michelin / T63
Rear:
Type With tube
Size 130/80-18-(66R) / 130/80-18-(66S)
Manufacturer/model Pirelli / MT70 - Michelin / T63
Maximum load* 180 kg •••
Tire air pressure
(measured on cold tires):
Up to 90 kg* Front 200 kPa; 2.00 kgf/cm
2; 2.00 bar •••
Rear 220 kPa; 2.20 kgf/cm2; 2.20 bar •••
90 kg–maximum* Front 210 kPa; 2.10 kgf/cm2; 2.10 bar •••
Rear 240 kPa; 2.40 kgf/cm2; 2.40 bar •••
Off-road riding Front 150 kPa; 1.50 kgf/cm2; 1.50 bar •••
Rear 160 kPa; 1.60 kgf/cm2; 1.60 bar •••
High-speed riding Front 210 kPa; 2.10 kgf/cm2; 2.10 bar •••
Rear 240 kPa; 2.40 kgf/cm2; 2.40 bar •••
* Total weight of rider, passenger,
cargo and accessories
Wheels
Front:
Type Spoke wheel
Size 21” x 1.85
Rear:
Type Spoke wheel
Size 18” x MT 2.50
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SPECMAINTENANCE SPECIFICATIONS
2-8
Item Standard Limit
Ballancer
Ballancer drive method Gear
Clutch
Clutch release method Inner push, cam push
Friction plate thickness 2.72 - 2.88 mm •••
Wear limit ••• 2.60 mm
Plate quantity 6 pcs
Friction plate thickness 2.94 - 3.06 mm •••
Wear limit ••• 2.8 mm
Plate quantity 2 pcs
Clutch plate thickness 1.20 mm •••
Plate quantity 7 pcs
Max. warpage ••• 0.20 mm
Clutch spring free length 42.8 mm •••
Plate quantity 5 pcs
Clutch housing thrust clearance 0.070 - 0.071 mm •••
Transmission
Max. main axle runout ••• 0.08 mm
Max. drive axle runout ••• 0.08 mm
Shift mechanism type Cam drum and guide bar
Carburetor
ID mark 5CH5 10
Main jet #1:#150 #2:#145
Main air jet #1:1.0 #2:0.9
Jet needle #1:5C5A-3/5 #2:5Y18-3/5
Needle jet 2.600
Cutaway 4.00
Pilot air jet 1 # 0.8 mm
Pilot jet # 50
Bypass 1 # 1.0
Pilot screw turns out 2-3/4 +/- 1/2
Valve seat size 2.5
Starter jet 1 # 74
Float height 6.0 - 8.0 mm •••
Engine idle speed1,150-1,450 r/min •••
CO% 1.5 - 3 •••
Intake vacuum 30.6-33.36 kPa - 230-250 mm Hg •••
Lubrication systemDry sump
Oil filter type Paper type
Oil pump:
Oil pump type Trochoid type
Inner rotor to outer rotor tip clearance 0.12 mm 0.20 mm
Outer rotor to pump housing
clearance 0.030 - 0.080 mm 0.150 mm
Bypass valve opening pressure 80.0 - 120.0 kPa (0.8 - 1.2 kgf/cm
2) •••
Relief valve operating pressure 80.0 - 120.0 kPa (0.8 - 1.2 kgf/cm2) •••
Oil pressure (hot) 13.0 kPa (0.13 kgf/cm2)/1,300 r/min •••
Pressure check location Oil filter chamber •••
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2-20
SPECLUBRlCATlON POINTS AND LUBRICANT TYPE
LUBRlCATlON POINTS AND LUBRICANT TYPES
ENGINE
Lubrication points (part name) Lubricant type
Oil seal edges (completely)
Bearing retainer
Rod pins
Rod (big end)
Piston and piston rings
Hub (weight drive sprocket)
Piston pin
Valve stim and guide
Oil seal (valve stim end)
Rocker shaft and rocker arm
Cam and bearing (camshaft)
Rotor and rotor housing (oil pump)
Push rod (clutch)
Primary driven gear and main shaft
Sliding gear (transmission)
Idle gear (transmission)
Shift forks and bar
Shift cam and bearing (gearshift cam)
Shift shaft
Rod housing coupled surfaces Bonding agent (rapid seal adhesive)®
Yamaha bond No. 1215®
Coupled surfaces (cylinder head and cylinder head cover) Bonding agent (rapid seal adhesive)®
Yamaha bond No. 1215®
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SPECLUBRICATION LAYOUT
2-25
(1) Oil pump
(2) Oil filter
(3) Oil delivery hose
(4) Transmission
(5) Oil strainer[A] DELIVERY
[B] RETRIEVAL
A
B
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CHASDRIVE CHAIN, DRIVE SPROCKET AND REAR WHEEL SPROCKET
4-83
6. Remove:
•Swingarm
•Drive chain
Refer to “REAR SHOCK ABSORBER
REMOVAL” and “SWINGARM REMOVAL”
sections.
DRIVE CHAIN INSPECTION
1. Measure:
•Length of 10 links (drive chain)
Out of specification ➔Replace drive
chain.
Maximum lenght of 10 links (a): 150.2 mm
NOTE:
•Stretch the chain by hand to measure it.
•The length of the 10 links is recorded between
the inside of the link pins (1) and (11) as
shown.
•The length of the 10 links is measured at var-
ious points.
2. Clean:
•Drive chain
Immerge in kerosene and brush thorough-
ly to remove as much dirt as possible.
Remove from kerosene and allow to dry.
This motorcycle is fitted with a chain with
small O-Rings (1) fitted between its plates.
Vapour cleaning, pressurised washing and
certain types of solvents may damage these
seal rings.
To clean the transmission chain use only
kerosene.
CAUTION:
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ENG
CHAPTER 5. ENGINE
ENGINE REMOVAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
MUFFLER, EXHAUST PIPE, ENGINE PROTECTOR, DRIVE SPROCKET,
CRANKCASE COVER, DRIVE SPROCKET AND SHIFT PEDAL . . . . . . . . . . . . . . . 5-1
ENGINE MOUNTING BOLT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4
ENGINE DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5
CYLINDER HEAD, CYLINDER, CAMSHAFT AND PISTON . . . . . . . . . . . . . . . . . . . . 5-5
INTERMEDIATE STARTER GEAR, CRANKCASE COVER (L)
AND GENERATOR STATOR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8
CRANKCASE COVER (R), CLUTCH, PRIMARY DRIVE GEAR
AND BALANCER SHAFT GEAR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9
OIL PUMP AND SHIFT LEVER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-12
AC GENERATOR AND TIMING CHAIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-13
CRANKCASE(R). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-14
GEARBOX AND TRANSMISSION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-16
BALANCER SHAFT AND CRANKSHAFT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-17
OILSTRAINER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-17
ROCKER ARMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-18
VALVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-19
INSPECTION AND REPAIR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-21
CYLINDER HEAD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-21
VALVES AND VALVE GUIDES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-22
VALVESEAT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-23
VALVE SPRINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-27
CAMSHAFT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-28
ROCKER ARMS AND ROCKER SHAFT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-28
CAMSHAFT CHAIN AND SPROCKET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-29
CAMSHAFT CHAIN GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-30
CYLINDER AND PISTON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-30
PISTON RINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-32
PISTONPIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-33
CLUTCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-33
OILPUMP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-35
PRIMARY TRANSMISSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-35
TRANSMISSION AND GEARBOX. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-36
SHIFT SHAFT AND STOPPER LEVER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-37
STARTER TRANSMISSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-38
CRANKSHAFT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-39
BALANCER SHAFT DRIVE
AND DRIVEN GEARS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-40
CRANKCASE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-40
BEARING AND OIL SEAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-40
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ENG
ENGINE ASSEMBLY AND SETTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-41
VALVES AND ROCKER ARMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-41
VALVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-42
ROCKER ARMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-43
CRANKSHAFT AND BALANCER SHAFT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-44
TRANSMISSION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-46
GEARBOX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-47
TRANSMISSION AND GEARBOX. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-48
ENGINE OIL PUMP AND OIL STRAINER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-49
CRANKCASE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-50
ENGINE OIL STRAINER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-51
CRANKCASE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-51
SHIFT SHAFT AND OIL PUMP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-52
TIMING CHAIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-54
PISTON AND RINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-55
CYLINDER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-56
CYLINDER HEAD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-57
CAMSHAFT AND TIMING CHAIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-58
PISTON, CYLINDER, CYLINDER HEAD AND CAMSHAFT . . . . . . . . . . . . . . . . . . . 5-59
AC GENERATOR.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-65
OIL FILTER AND OIL HOSES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-67
BALANCER SHAFT GEAR AND PRIMARY
TRANSMISSION GEAR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-68
CLUTCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-70
STARTER GEARS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-73
STARTER NEUTRAL GEAR AND CRANKCASE COVER (L) . . . . . . . . . . . . . . . . . 5-74
ENGINE REASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-76
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ENGINE DISASSEMBLY
5-16
ENG
GEARBOX AND TRANSMISSION
1. Remove:
•Guide bar (1)
•Shift cam (2)
•Selector fork # 3 (3)
•Selector fork # 2 (4)
•Selector fork # 1 (5)
2. Remove:
•Transmission assembly unit (1)
3. Remove:
•Shift shaft # 1 (1)
•Shift shaft # 2 (2)
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