2000 YAMAHA YZ426F wheel

4 - 88
ENGTRANSMISSION, SHIFT CAM, SHIFT FORK
2. Install:
l2nd wheel gear (27T) 1
l4th wheel gear (24T) 2
l3rd wheel gear (23T) 3
l5th wheel gear (20T) 4
l1st wheel gear (24T) 5
lO-ring 6
To drive axle 7.
NOTE:
lApply the molybdenum disulfide oil on the
1st, 2nd and 3rd wheel gears inner circum-
ference and on the end surface.
lApply the molybdenum disulfide oil on the
4th and 5th wheel gears inner circumfer-
ence.
lApply the lithium soap base grease on the O-
ring.
3. Install:
lPlain washer 1
lCirclip 2
NOTE:
lBe sure the circlip sharp-edged corner a is
positioned opposite side to the plain washer
and gear b.
lBe sure the circlip end c is positioned at
axle spline groove d.
New
4. Install:
lSpacer 1
NOTE:
lApply the lithium soap base grease on the oil
seal lip.
lWhen installing the spacer into the crank-
case, pay careful attention to the crankcase
oil seal lip.

4 - 89
ENGTRANSMISSION, SHIFT CAM, SHIFT FORK
5. Install:
lShift fork 1 (L) 1
lShift fork 2 (C) 2
lShift fork 3 (R) 3
lShift cam 4
To main axle and drive axle.
NOTE:
lApply the molybdenum disulfide oil on the
shift fork grooves.
lMesh the shift fork #1 (L) with the 4th wheel
gear 5 and #3 (R) with the 5th wheel gear
7 on the drive axle.
lMesh the shift fork #2 (C) with the 3rd pinion
gear 6 on the main axle.
6. Install:
lTransmission assembly 1
To crankcase (left) 2.
NOTE:
Apply the engine oil on the bearings and guide
bars.
7. Check:
lShifter operation
lTransmission operation
Unsmooth operation ® Repair.

5 - 1
CHAS

EC500000
CHASSIS
EC590000
FRONT WHEEL AND REAR WHEEL
EC598000
FRONT WHEEL
FRONT WHEEL AND REAR WHEEL
Extent of removal:
1
Front wheel removal
2
Wheel bearing removal
3
Break disc removal
Extent of removal Order Part name Q’ty Remarks
Preparation for removal
FRONT WHEEL REMOVAL
Hold the machine by placing the
suitable 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”.
10Brake disk
1
WARNING
Support the machine securely so there is nodanger of it falling over.
2
31
3

5

5 - 2
CHAS

EC598100
REAR WHEEL
Extent of removal:
1
Rear wheel removal
2
Wheel bearing removal
3
Break disc removal
Extent of removal Order Part name Q’ty Remarks
Preparation for removal
REAR WHEEL REMOVAL
Hold the machine by placing the
suitable 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”.
10Brake disk
1
WARNING
Support the machine securely so there is nodanger of it falling over.
2
31
3

FRONT WHEEL AND REAR WHEEL

5 - 3
CHAS

FRONT WHEEL AND REAR WHEEL
EC593000
REMOVAL POINTS
EC523101
Rear wheel
1. Remove:
l
Wheel
1

NOTE:

Push the wheel forward and remove the drive
chain
2
.
EC513201
Wheel bearing (if necessary)
1. Remove:
l
Bearing
1

NOTE:

Remove the bearing using a general bearing
puller
2
.
EC594000
INSPECTION
EC514100
Wheel
1. Measure:
l
Wheel runout
Out of limit
®
Repair/replace.
2. Inspect:
l
Bearing
Rotate inner race with a finger.
Rough spot/seizure
®
Replace.
NOTE:

Replace the bearings, oil seal and wheel collar
as a set.
Wheel runout limit:
Radial
1
: 2.0 mm (0.08 in)
Lateral
2
: 2.0 mm (0.08 in)

5 - 4
CHAS

FRONT WHEEL AND REAR WHEEL
EC514200
Wheel axle
1. Measure:
l
Wheel axle bends
Out of specification
®
Replace.
Use the dial gauge
1
.
NOTE:

The bending value is shown by one half of the
dial gauge reading.
WARNING

Do not attempt to straighten a bent axle.
Wheel axle bending limit:
0.5 mm (0.020 in)
EC514302
Brake disc
1. Measure:
l
Brake disc deflection
Use the dial gauge
1
.
Out of specification
®
Inspect wheel
runout.
If wheel runout is in good condition,
replace the brake disc.
2. Measure:
l
Brake disc thickness
a

Out of limit
®
Replace.
Disc deflection limit:
0.15 mm (0.006 in)
Disc wear limit:
Standard

Front
3.0 mm (0.12 in) 2.5 mm (0.10 in)
Rear
4.0 mm (0.16 in) 3.5 mm (0.14 in)

5 - 5
CHAS

FRONT WHEEL AND REAR WHEEL
EC595000
ASSEMBLY AND INSTALLATION
EC595100
Front wheel
1. Install:
l
Bearing (left)
1

l
Spacer
2

l
Bearing (right)
3

l
Oil seal
4

NOTE:

l
Apply the lithium soap base grease on the
bearing and oil seal lip when installing.
l
Use a socket that matches the outside diam-
eter of the race of the bearing.
l
Left side of bearing shall be installed first.
l
Install the oil seal with its manufacture’s
marks or numbers facing outward.
ACHTUNG:CAUTION:
Do not strike the inner race of the bearing.
Contact should be made only with the outer
race.
2. Install:
lBrake disc 1
lBolt (brake disc) 2
NOTE:
Tighten the bolts in stage, using a crisscross
pattern.
New
T R..12 Nm (1.2 m · kg, 8.7 ft · lb)
3. Install:
lCollar 1
NOTE:
lApply the lithium soap base grease on the oil
seal lip.
lInstall the collars with their projections a
facing the wheel.
4. Install:
lWheel
NOTE:
Install the brake disc 1 between the brake
pads 2 correctly.

5 - 6
CHASFRONT WHEEL AND REAR WHEEL
5. Install:
lWheel axle 1
NOTE:
Apply the lithium soap base grease on the
wheel axle.
6. Install:
lNut (wheel axle) 1
T R..105 Nm (10.5 m · kg, 75 ft · lb)
7. Tighten:
lBolt (axle holder) 1
NOTE:
Before tightening the bolt, fit the wheel axle to
the axle holder by stroking the front fork sev-
eral times with the front brake applied.
8. Install:
lBrake hose 1
To brake hose holder 2.
NOTE:
Before tightening the bolt (brake hose holder),
pass the brake hose in front of the axle boss
a, then fit it into the hose groove b so that the
brake hose does not contact the nut (wheel
axle).
T R..23 Nm (2.3 m · kg, 17 ft · lb)
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)