2001 YAMAHA YZ125LC steering

CHAPTER 4
ENGINE
SEAT, FUEL TANK AND SIDE
COVERS.....................................................4-1
EXHAUST PIPE AND SILENCER..............4-3
RADIATOR..................................................4-4
CARBURETOR AND REED VALVE...........4-7
CYLINDER HEAD , CYLINDER AND
PISTON.....................................................4-17
CLUTCH AND PRIMARY DRIVEN
GEAR.......................................................4-30
KICK AXLE, SHIFT SHAFT AND
PRIMARY DRIVE GEAR...........................4-38
YPVS GOVERNOR...................................4-46
WATER PUMP..........................................4-49
CDI MAGNETO.........................................4-53
ENGINE REMOVAL..................................4-57
CRANKCASE AND CRANKSHAFT.........4-62
TRANSMISSION, SHIFT CAM AND
SHIFT FORK.............................................4-69
CHAPTER 5
CAHSSIS
FRONT WHEEL AND REAR WHEEL........5-1
FRONT BRAKE AND REAR BRAKE.......5-10
FRONT FORK...........................................5-27
HANDLEBAR............................................5-40
STEERING................................................5-47
SWINGARM..............................................5-52
REAR SHOCK ABSORBER.....................5-59
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1-2
GEN
INFO
MACHINE IDENTIFICATION
EC120001
MACHINE IDENTIFICATION
There are two significant reasons for knowing
the serial number of your machine:
1. When ordering parts, you can give the num-
ber to your Yamaha dealer for positive iden-
tification of the model you own.
2. If your machine is stolen, the authorities will
need the number to search for and identify
your machine.
EC121001
VEHICLE IDENTIFICATION NUMBER
(For USA, CDN, AUS, NZ and E)
The vehicle identification number 1is stamped
on the right of the steering head pipe.
EC122001
FRAME SERIAL NUMBER
(For F, D, GB, I and ZA)
The frame serial number 1is stamped on the
right of the steering head pipe.
EC123001
ENGINE SERIAL NUMBER
The engine serial number 1is stamped into the
elevated part of the right-side of the engine.
EC124000
MODEL LABEL
The model label 1is affixed to the frame under
the rider’s seat. This information will be needed
to order spare parts.
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1-8
GEN
INFO
SPECIAL TOOLS
Part number Tool name / How to use IIIustration
YU-24460-01, 90890-01325Radiator cap testerYU-24460-01 90890-01325
YU-33984, 90890-01352 AdapterYU-33984 90890-01352
These tools are used for checking the cooling
system.
YU-33975, 90890-01403 Ring nut wrench
YU-33975 90890-01403
This tool is used when tighten the steering ring nut
to specification.
YM-1423, 90890-01423 Damper rod holder
YM-1423 90890-01423
Use this tool to remove and install the damper rod.
YM-01442, 90890-01442 Fork seal driver
YM-01442 90890-01442
This tool is used when install the fork oil seal.
YU-3112-C, Yamaha pocket tester
YU-3112-C 90890-03112
90890-03112
Use this tool to inspect the coil resistance,
output voltage and amperage.
YM-91042, 90890-04086 Clutch holding tool
YM-91042 90890-04086
This tool is used to hold the clutch when removing
or installing the clutch boss securing nut.
YM-34487 Dynamic spark tester
YM-34487 90890-06754
90890-06754 Ignition checker
This instrument is necessary for checking the igni-
tion system components.
ACC-QUICK-GS-KT Quick gasket
®ACC-QUICK-GS-KT 90890-85505
90890-85505 YAMAHA Bond No. 1215
This sealant (Bond) is used for crankcase mating
surface, etc.
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1-16
GEN
INFO
TORQUE-CHECK POINTS
EC1A0012
TORQUE-CHECK POINTS
Frame construction Frame to rear frame
Combined seat and tank Fuel tank to frame
Engine mounting Frame to engine
Steering Steering shaft to Steering shaft to frame
handlebar Steering shaft to handle crown
Handle crown to handlebar
Suspension Front Steering shaft to Front fork to handle crown
front fork Front fork to under bracket
Rear For link type Assembly of links
Link to frame
Link to shock absorber
Link to swingarm
Rear Installation of shock Shock absorber to frame
absorber
Rear Installation of swingarm Tightening of pivot shaft
Wheel Installation of wheel Front Tightening of front axle
Tightening of axle holder
Rear Tightening of rear axle
Wheel to sprocket
Brake Front Caliper to front fork
Brake disc to wheel
Tightening of union bolt
Master cylinder to handlebar
Tightening of air bleeder
Rear Brake disc to wheel
Tightening of union bolt
Master cylinder to frame
Tightening of air bleeder
Fuel system Fuel tank to fuel cock
NOTE:
Concerning the tightening torque, refer to “
MAINTENANCE SPECIFICATIONS” section in
the CHAPTER 2.
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2-7
SPECMAINTENANCE SPECIFICATIONS
EC212201
CHASSIS
Item Standard Limit
Steering system:
Steering bearing type Taper roller bearing…
Front suspension: USA, CDN, ZA
EUROPE
AUS, NZ
Front fork travel
300 mm (11.8 in)¬…
Fork spring free length
460 mm (18.1 in)¬455 mm (17.9 in)
Spring rate, STD K=4.10 N/mm K=Approx.…
(0.410 kg/mm, 4.10 N/mm
23.0 lb/in) (0.410 kg/mm,
23.0 lb/in)
Optional spring/Spacer Yes¬…
Oil capacity 573 cm
3¬…
(20.2 Imp oz,
19.4 US oz)
Oil level
135 mm (5.31 in)¬…
80~150 mm ¬…
(From top of outer tube with inner tube(3.15~5.91 in)
and damper rod fully compressed
without spring.)
Oil grade Suspension oil ¬…
“01”
Inner tube outer diameter 46 mm (1.81 in)¬…
Front fork top end 5 mm (0.20 in)¬…
Rear suspension: USA, CDN, ZA
EUROPE
AUS, NZ
Shock absorber travel
132 mm (5.20 in)¬…
Spring free length
260 mm (10.24 in) 275 mm (10.83 in)…
Fitting length
248 mm (9.76 in)262 mm (10.31 in)…

242~260 mm 257~275 mm…
(9.53~10.24 in)
(10.12~10.83 in)
Spring rate, STD K=46.0 N/mm K=Approx.…
(4.60 kg/mm, 48.0 N/mm
257.6 lb/in) (4.80 kg/mm,
268.8 lb/in)
Optional spring Yes¬…
Enclosed gas pressure 1,000 kPa ¬…
(10 kg/cm
2,
142 psi)
Swingarm:
Swingarm free play limit
End…
1.0 mm (0.04 in)
Side clearance…
0.2~0.9 mm
(0.008~0.035 in)
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2-9
SPECMAINTENANCE SPECIFICATIONS
NOTE:
1. First, tighten the ring nut approximately 38 Nm (3.8 m•kg, 27 ft•lb) by using the ring nut wrench,
then loosen the ring nut one turn.
2. Retighten the ring nut 7 Nm (0.7 m•kg, 5.1 ft•lb).
Part to be tightened Thread size Q'tyT ightening torqueNm m•kg ft•lb
Handle crown and outer tube M 8 ´1.25 4 23 2.3 17
Under bracket and outer tube M 8 ´1.25 4 20 2.0 14
Handle crown and steering shaft M24 ´1.0 1 145 14.5 105
Handlebar holder (upper) M 8 ´1.25 4 28 2.8 20
Steering ring nut M28 ´1.0 1 Refer to NOTE
Front fork and cap bolt M48 ´1.0 2 30 3.0 22
Front fork and base valve M30 ´1.0 2 55 5.5 40
Cap bolt and damper rod (front fork) M12 ´1.25 2 29 2.9 21
Bleed screw (front fork) and cap bolt M 5 ´0.8 2 1 0.1 0.7
Front fork and protector M 6 ´1.0 6 10 1.0 7.2
Cable guide (front brake hose) and guide stayM 5 ´0.8 1 4 0.4 2.9
Front fork and brake hose holder M 6 ´1.0 2 10 1.0 7.2
Front fork and hose cover M 8 ´1.25 1 16 1.6 11
Front fork and hose cover M 6 ´1.0 1 7 0.7 5.1
Throttle cable cap M 4 ´0.7 2 1 0.1 0.7
Front brake master cylinder and bracket M 6 ´ 1.0 2 9 0.9 6.5
Brake lever (bolt) M 6 ´1.0 1 6 0.6 4.3
(nut) M 6 ´1.0 1 6 0.6 4.3
Brake lever position locknut M 6 ´1.0 1 5 0.5 3.6
Clutch lever (bolt) M 6 ´1.0 1 2 0.2 1.4
Clutch lever holder M 5 ´0.8 2 4 0.4 2.9
Front brake master cylinder cap M 4 ´0.7 2 2 0.2 1.4
Front brake hose union bolt (master cylinder)M10 ´1.25 1 30 3.0 22
Front brake hose union bolt (caliper) M10 ´1.25 1 30 3.0 22
Front brake caliper and front fork M 8 ´1.25 2 23 2.3 17
Grip cap upper and lower M 6 ´1.0 2 4 0.4 2.9
Brake caliper (front and rear) and pad pin plugM10 ´1.0 1 3 0.3 2.2
Brake caliper (front and rear) and pad pin M10 ´1.0 1 18 1.8 13
Brake caliper (front and rear) and bleed screwM 8 ´1.25 1 6 0.6 4.3
Front wheel axle and nut M16 ´1.5 1 105 10.5 75
Front wheel axle holder M 8 ´1.25 4 23 2.3 17
Front brake disc and wheel hub M 6 ´1.0 6 12 1.2 8.7
Rear brake disc and wheel hub M 6 ´1.0 6 14 1.4 10
Brake pedal mounting M 8 ´1.25 1 26 2.6 19
s s
s s
s s
s s
s s
s s
s s
s s
s s
s s
s s
s s
s s
s s
s s
s s
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3-2
MAINTENANCE INTERVALS
INSP
ADJ
Item Remarks
COOLING SYSTEM
Check coolant level and leakagell
Check radiator cap operationl
Replace coolantlEvery two years
Inspect hosesl
OUTSIDE NUTS AND BOLTS Refer to “STARTING
RetightenllAND BREAK-IN” section
in the CHAPTER 1.
AIR FILTER
Clean and lubricatellUse foam air-filter oil
Replacel
FRAME
Clean and inspectll
FUEL TANK, COCK
Clean and inspectll
BRAKES
Adjust lever position and pedal heightll
Lubricate pivot pointll
Check brake disc surfacell
Check fluid level and leakagell
Retighten brake disc bolts, caliper bolts,
ll
master cylinder bolts and union bolts
Replace padsl
Replace brake fluidlEvery one year
FRONT FORKS
Inspect and adjustll
Replace oilllSuspension oil “01”
Replace oil seall
FRONT FORK OIL SEAL AND DUST SEAL
Clean and lubellLithium base grease
REAR SHOCK ABSORBER
Inspect and adjustll
Lube ll
Molybdenum disulfide grease
Retightenll
CHAIN GUARD AND ROLLERS
Inspectll
SWINGARM
Inspect and retightenll
RELAY ARM, CONNECTING ROD
Inspect and lubellMolybdenum disulfide grease
STEERING HEAD
Inspect free play and retightenll
Clean and lubelLithium base grease
Replace bearingl
TIRE, WHEELS
Inspect air pressure, wheel run-out,
ll
tire wear and spoke looseness
Retighten sprocket boltll
Inspect bearingsl
Replace bearingsl
LubricatelLithium base grease
THROTTLE, CONTROL CABLE
Check routing and connectionllYamaha cable lube or
LubricatellSAE 10W-30 motor oil
After
break-
inEvery
raceEvery
thirdEvery
fifthAs re-
quired
3
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3-4
PRE-OPERATION INSPECTION AND MAINTENANCE
INSP
ADJ
EC320000
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.
EC321000
GENERAL INSPECTION AND MAINTENANCE
Item Routine Page
Coolant Check that coolant is filled up to the radiator filler cap.
Check the cooling system for leakage.P3-5~9
Fuel Check that a fresh mixture of oil and gasoline is filled in
the fuel tank. Check the fuel line for leakage.P1-12
Transmission oil Check that the oil level is correct. Check the crankcase
for leakage.P3-12~14
Gear shifter and clutch Check that gears can be shifted correctly in order and
that the clutch operates smoothly.P3-9
Throttle grip/Housing Check that the throttle grip operation and free play
are correctly adjusted. Lubricate the throttle grip and P3-10~11
housing, if necessary.
Brakes Check the play of front brake and effect of front and
rear brake.P3-17~23
Chain Check chain slack and alignment. Check that the chain
is lubricated properly.P3-24~26
Wheels Check for excessive wear and tire pressure. Check for
loose spokes and have no excessive play.P3-34~35
Steering Check that the handlebar can be turned smoothly and
have no excessive play.P3-35~36
Front forks and Check that they operate smoothly and there is no oil
rear shock absorber leakage.P3-26~33
Cables (wires) Check that the clutch and throttle cables move smooth-
ly. Check that they are not caught when the handlebars —
are turned or when the front forks travel up and down.
Muffler Check that the muffler is tightly mounted and has no
cracks.P3-15~16
Sprocket Check that the driven sprocket tightening bolt is
not loose.P3-24
Lubrication Check for smooth operation. Lubricate if necessary. P3-37
Bolts and nuts Check the chassis and engine for loose bolts and nuts. P1-16
Lead connectors Check that the CDI magneto, CDI unit, and ignition coil
are connected tightly.P1-6
Settings Is the machine set suitably for the condition of the
racing course and weather or by taking into account the
P7-1~24
results of test runs before racing? Are inspection and
maintenance completely done?
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