wheel YAMAHA YZ250LC 2003 Owner's Manual

3-34
TIRE PRESSURE CHECK/SPOKES INSPECTION AND
TIGHTENING/WHEEL INSPECTIONINSP
ADJ
EC36Q001
TIRE PRESSURE CHECK
1. Measure:
9Tire pressure
Out of specification Adjust.
NOTE:
9Check the tire while it is cold.
9Loose bead stoppers allow the tire to slip off its
position on the rim when the tire pressure is
low.
9A tilted tire valve stem indicates that the tire
slips off its position on the rim.
9If the tire valve stem is found tilted, the tire is
considered to be slipping off its position.
Correct the tire position.
EC36S002
SPOKES INSPECTION AND TIGHTENING
1. Inspect:
9Spokes 1
Bend/Damage Replace.
Loose spoke Retighten.
2. Tighten:
9Spokes
NOTE:
Be sure to retighten these spokes before and af-
ter break-in. After a practice or a race check
spokes for looseness.
EC36T000
WHEEL INSPECTION
1. Inspect:
9Wheel runout
Elevate the wheel and turn it.
Abnormal runout Replace.
Standard tire pressure:
100 kPa (1.0 kgf/cm
2, 15 psi)
3 Nm (0.3 m•kg, 2.2 ft•lb)
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3-35
STEERING HEAD INSPECTION AND ADJUSTMENT
INSP
ADJ
2. Inspect:
9Bearing free play
Exist play Replace.
EC36U014
STEERING HEAD INSPECTION AND
ADJUSTMENT
1. Elevate the front wheel by placing a suitable
stand under the engine.
2. Check:
9Steering shaft
Grasp the bottom of the forks and gently
rock the fork assembly back and forth.
Free play Adjust steering head.
3. Check:
9Steering smooth action
Turn the handlebar lock to lock.
Unsmooth action Adjust steering ring
nut.
4. Adjust:
9Steering ring nut
Steering ring nut adjustment steps:
9Remove the number plate.
9Remove the handlebar and handle crown.
9Loosen the ring nut 1using the ring nut
wrench 2.
9Tighten the ring nut 3using ring nut wrench
4.
NOTE:
Set the torque wrench to the ring nut wrench
so that they form a right angle.
Ring nut wrench:
YU-33975/90890-01403
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4-42
KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE GEARENG
EC4C3000
REMOVAL POINTSEC483111
Primary drive gear
1. Loosen:
9Bolt (primary drive gear) 1
NOTE:
Place an aluminum plate abetween the teeth of
the primary drive gear 2and driven gear 3.
EC4B3101
Kick axle assembly
1. Remove:
9Kick axle assembly 1
NOTE:
Unhook the torsion spring 2from the hole ain
the crankcase.
EC4C3101
Shift guide and shift lever assembly
1. Remove:
9Bolt (shift guide)
9Shift guide 1
9Shift lever assembly 2
NOTE:
The shift lever assembly is disassembled at the
same time as the shift guide.
EC4C4000
INSPECTION
EC4C4200
Kick axle and ratchet wheel
1. Check:
9Ratchet wheel 1smooth movement
Unsmooth movement
Replace.
9Kick axle 2
Wear/Damage
Replace.
9Spring 3
Broken
Replace.
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4-43
KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE GEARENG
EC4B4400
Shift shaft
1. Inspect:
9Shift shaft 1
Bend/Damage
Replace.
9Spring 2
Broken
Replace.
EC484300
Primary drive gear and primary driven gear
1. Inspect:
9Primary drive gear 1
9Primary driven gear 2
Wear/Damage
Replace.
EC4C4400
Stopper lever
1. Inspect:
9Stopper lever 1
Wear/Damage
Replace.
9Bearing 2
Rotate outer race with a finger.
Rough spot/Seizure
Replace the stopper
lever.
9Tension spring 3
Broken
Replace.
EC4C4100
Shift guide and shift lever assembly
1. Inspect:
9Shift guide 1
9Shift lever 2
9Pawl 3
9Pawl pin 4
9Spring 5
Wear/Damage
Replace.
EC4C4300
Kick gear, kick idle gear and ratchet wheel
1. Inspect:
9Kick gear 1
9Kick idle gear 2
9Ratchet wheel 3
9Gear teeth a
9Ratchet teeth b
Wear/Damage
Replace.
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4-45
KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE GEARENG
EC4C5310
Shift shaft
1. Install:
9Roller 1
9Plain washer 2
9Shift shaft 3
NOTE:
Apply the transmission oil on the roller and shift
shaft.
2. Install:
9Torsion spring 1
To kick axle 2.
NOTE:
Make sure the stopper aof the torsion spring
fits into the hole bon the kick axle.
EC4C5602
Kick axle assembly
1. Install:
9Kick gear 1
9Plain washer 2
9Circlip 3
9Ratchet wheel 4
9Spring 5
9Plain washer 6
9Circlip 7
To kick axle 8.
NOTE:
9Apply the transmission oil on the kick gear
inner circumference.
9Align the punch mark aon the ratchet wheel
with the punck mark bon the kick axle.
4. Install:
9Bolt (shift guide) 1
10 Nm (1.0 m•kg, 7.2 ft•lb)
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4-57
CDI MAGNETOENG
EC4L5000
ASSEMBLY AND INSTALLATION
EC4L5172
CDI magneto
1. Install:
9Stator 1
9Screw (stator) 2
NOTE:
Temporarily tighten the screw (stator) at this
point.
2. Remove:
9Rotor 1
Use the flywheel puller 2.
NOTE:
When installing the flywheel puller, turn it coun-
terclockwise.
EC4L3000
REMOVAL POINTS
EC4L3102
Rotor
1. Remove:
9Nut (rotor) 1
9Plain washer 2
Use the rotor holding tool 3.
EC4L4000
INSPECTION
EC4L4101
CDI magneto
1. Inspect:
9Rotor inner surface a
9Stator outer surface b
Damage
Inspect the crankshaft runout
and crankshaft bearing.
If necessary, replace CDI magneto and/or
stator.
EC4L4200
Woodruff key
1. Inspect:
9Woodruff key 1
Damage
Replace.
Rotor holding tool:
YU-1235/90890-01235
Flywheel puller:
YM-1189/90890-01189
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4-75
TRANSMISSION, SHIFT CAM AND SHIFT FORKENG
4. Install:
9Spacer 1
NOTE:
9Apply the lithium soap base grease on the oil
seal lip.
9When installing the spacer into the crankcase,
pay careful attention to the crankcase oil seal
lip.
9Install the spacer with its chamfered side a
facing the crankcase.
3. Install:
9Plain washer 1
9Circlip 2
NOTE:
9Be sure the circlip sharp-edged corner ais
positioned opposite side to the plain washer
and gear b.
9Be sure the circlip end cis positioned at axle
spline groove d.
2. Install:
92nd wheel gear (23 T) 1
94th wheel gear (24 T) 2
93rd wheel gear (23 T) 3
95th wheel gear (20 T) 4
91st wheel gear (27 T) 5
9O-ring 6
To drive axle 7.
NOTE:
9Apply the molybdenum disulfide oil on the 1st,
2nd and 3rd wheel gears inner circumference
and on the end surface.
9Apply the molybdenum disulfide oil on the 4th
and 5th wheel gears inner circumference.
9Apply the lithium soap base grease on the O-
ring.
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4-76
TRANSMISSION, SHIFT CAM AND SHIFT FORKENG
5. Install:
9Shift fork 1 (L) 1
9Shift fork 2 (C10) 2
9Shift fork 3 (R) 3
9Shift cam 4
To main axle and drive axle.
NOTE:
9Apply the molybdenum disulfide oil on the shift
fork grooves.
9Mesh the shift fork #1 (L) with the 4th wheel
gear 5and #3 (R) with the 5th wheel gear 7
on the drive axle.
9Mesh the shift fork #2 (C10) with the 3rd pinion
gear 6on the main axle.
6. Install:
9Transmission assembly 1
To crankcase (left) 2.
NOTE:
Apply the transmission oil on the bearings and
guide bars.
7. Check:
9Shifter operation
9Transmission operation
Unsmooth operation
Repair.
5UP-9-30-4C 5/24/02 5:33 PM Page 54

5-1
CHASFRONT WHEEL AND REAR WHEEL
Extent of removal Order Part name Q’ty Remarks
FRONT WHEEL REMOVAL
Preparation for
Hold the machine by placing the
removalsuitable stand under the engine.
1 Hose cover 1
2 Bolt (brake hose holder) 2 Only loosening.
3 Bolt (axle holder) 4 Only loosening.
4 Nut (front wheel axle) 1
5 Front wheel axle 1
6 Front wheel 1
7 Collar 2
8 Oil seal 2
9 Bearing 2 Refer to “REMOVAL POINTS”.
10 Brake disc 1
EC500000
CHASSISEC590000
FRONT WHEEL AND REAR WHEELEC598000
FRONT WHEEL
2
13
3
Extent of removal:1Front wheel removal2Wheel bearing removal3Brake disc removal
w
Support the machine securely so there is no dan-
ger of it falling over.
23 Nm (2.3 m•kg, 17 ft•lb)
23 Nm (2.3 m•kg, 17 ft•lb)
105 Nm (10.5 m•kg, 75 ft•lb)
16 Nm (1.6 m•kg, 11 ft•lb)
7 Nm (0.7 m•kg, 5.1 ft•lb)12 Nm (1.2 m•kg, 8.7 ft•lb)
10 Nm (1.0 m•kg, 7.2 ft•lb)
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5-2
CHASFRONT WHEEL AND REAR WHEEL
EC598100
REAR WHEEL
Extent of removal:1Rear wheel removal2Wheel bearing removal3Brake disc removal
Extent of removal Order Part name Q’ty Remarks
REAR WHEEL REMOVAL
Preparation for
Hold the machine by placing the
removalsuitable stand under the engine.
1 Nut (rear wheel axle) 1
2 Rear wheel axle 1
3 Chain puller 2
4 Rear wheel 1 Refer to “REMOVAL POINTS”.
5 Collar 2
6 Driven sprocket 1
7 Oil seal 2
8 Circlip 1
9 Bearing 2 Refer to “REMOVAL POINTS”.
10 Brake disc 1
2
13
3
w
Support the machine securely so there is no dan-
ger of it falling over.
125 Nm (12.5 m•kg, 90 ft•lb)
14 Nm (1.4 m•kg, 10 ft•lb)
16 Nm (1.6 m•kg, 11 ft•lb)
16 Nm (1.6 m•kg, 11 ft•lb)
42 Nm (4.2 m•kg, 30 ft•lb)
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