2001 YAMAHA YZ426F wheel

4 - 94
ENG

TRANSMISSION, SHIFT CAM AND SHIFT FORK
2. Install:
l
2nd wheel gear (23T)
1

l
4th wheel gear (24T)
2

l
3rd wheel gear (23T)
3

l
5th wheel gear (20T)
4

l
1st wheel gear (24T)
5

l
O-ring
6
To drive axle
7
.
NOTE:

l
Apply the molybdenum disulfide oil on the
1st, 2nd and 3rd wheel gears inner circum-
ference and on the end surface.
l
Apply the molybdenum disulfide oil on the
4th and 5th wheel gears inner circumfer-
ence.
l
Apply the lithium soap base grease on the O-
ring.
3. Install:
l
Plain washer
1

l
Circlip
2

NOTE:

l
Be sure the circlip sharp-edged corner
a
is
positioned opposite side to the plain washer
and gear
b
.
l
Be sure the circlip end
c
is positioned at
axle spline groove
d
.
New

4. Install:
l
Collar
1

NOTE:

l
Apply the lithium soap base grease on the oil
seal lip.
l
When installing the spacer into the crank-
case, pay careful attention to the crankcase
oil seal lip.

4 - 95
ENG

TRANSMISSION, SHIFT CAM AND SHIFT FORK
5. Install:
l
Shift fork 1 (L)
1

l
Shift fork 2 (C)
2

l
Shift fork 3 (R)
3

l
Shift cam
4

To main axle and drive axle.
NOTE:

l
Apply the molybdenum disulfide oil on the
shift fork grooves.
l
Mesh the shift fork #1 (L) with the 4th wheel
gear
5
and #3 (R) with the 5th wheel gear
7
on the drive axle.
l
Mesh the shift fork #2 (C) with the 3rd pinion
gear
6
on the main axle.
6. Install:
l
Transmission assembly
1

To crankcase (left)
2
.
NOTE:

Apply the engine oil on the bearings and guide
bars.
7. Check:
l
Shifter operation
l
Transmission 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 removal2 Wheel bearing removal
3 Break disc removal
Extent of removal Order Part name Q’ty Remarks
Preparation for removalFRONT WHEEL REMOVAL
Hold the machine by placing the
suitable stand under the engine.
WARNING
Support the machine securely so there is nodanger of it falling over.
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
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.
WARNING

Support the machine securely so there is no
danger of it falling over.
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
2
31
3

FRONT WHEEL AND REAR WHEEL

5 - 3
CHASFRONT WHEEL AND REAR WHEEL
EC593000
REMOVAL POINTS
EC523101
Rear wheel
1. Remove:
lWheel 1
NOTE:
Push the wheel forward and remove the drive
chain 2.
EC513201
Wheel bearing (if necessary)
1. Remove:
lBearing 1
NOTE:
Remove the bearing using a general bearing
puller 2.
EC594000
INSPECTION
EC514100
Wheel
1. Measure:
lWheel runout
Out of limit ® Repair/replace.
2. Inspect:
lBearing
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
CHASFRONT WHEEL AND REAR WHEEL
EC514200
Wheel axle
1. Measure:
lWheel 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)
EC594200
Brake disc
1. Measure:
lBrake disc deflection (only rear brake
disc)
Use the dial gauge 1.
Out of specification ® Inspect wheel
runout.
If wheel runout is in good condition,
replace the brake disc.
2. Measure:
lBrake disc thickness a
Out of limit ® Replace.
Disc deflection limit:
Standard
Rear —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
CHASFRONT WHEEL AND REAR WHEEL
EC595000
ASSEMBLY AND INSTALLATION
EC595100
Front wheel
1. Install:
lBearing (left) 1
lSpacer 2
lBearing (right) 3
lOil seal 4
NOTE:
lApply the lithium soap base grease on the
bearing and oil seal lip when installing.
lUse a socket that matches the outside diam-
eter of the race of the bearing.
lLeft side of bearing shall be installed first.
lInstall 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)