wheel YAMAHA YZ426F 2001 Owner's Manual

4 - 66
ENGKICK AXLE AND SHIFT SHAFT
KICK AXLE AND SHIFT SHAFT
KICK AXLE AND SHIFT SHAFT
Extent of removal:1 Kick axle removal2 Kick axle disassembly
3 Shift shaft removal4 Segment removal
Extent of removal Order Part name Q’ty Remarks
KICK AXLE AND SHIFT SHAFT
REMOVAL
Preparation for removal Shift pedal Refer to “CDI MAGNETO” section.
Oil pump Refer to “OIL PUMP” section.
1 Kick idle gear 1
2 Kick axle assembly 1 Refer to “REMOVAL POINTS”.
3 Spring guide 1
4 Torsion spring 1
5 Ratchet wheel 1
6 Kick gear 1
7 Kick axle 1
8 Plain washer 1
9 Shift shaft 1
10Collar
1
3
2
1
4
1

4 - 68
ENGKICK AXLE AND SHIFT SHAFT
REMOVAL POINTS
EC4B3101
Kick axle assembly
1. Remove:
lKick axle assembly 1
NOTE:
Unhook the torsion spring 2 from the hole a
in the crankcase.
EC4C3101
Shift guide and shift lever assembly
1. Remove:
lBolt (shift guide)
lShift guide 1
lShift lever assembly 2
NOTE:
The shift lever assembly is disassembled at
the same time as the shift guide.
EC4N3100
Segment
1. Remove:
lBolt (segment) 1
lSegment 2
NOTE:
Turn the segment counterclockwise until it
stops and loosen the bolt.
INSPECTION
EC4C4200
Kick axle and ratchet wheel
1. Check:
lRatchet wheel 1 smooth movement
Unsmooth movement ® Replace.
lKick axle 2
Wear/damage ® Replace.
lSpring 3
Broken ® Replace.
EC4C4300
Kick gear, kick idle gear and ratchet wheel
1. Inspect:
lKick gear 1
lKick idle gear 2
lRatchet wheel 3
lGear teeth a
lRatchet teeth b
Wear/damage ® Replace.

4 - 71
ENGKICK AXLE AND SHIFT SHAFT
4. Install:
lBolt (shift guide) 1
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
EC4C5301
Shift shaft
1. Install:
lRoller 1
lCollar 2
lTorsion spring 3
lShift shaft 4
NOTE:
Apply the engine oil on the roller and shift
shaft.
Kick axle assembly
1. Install:
lKick gear 1
lPlain washer 2
lCirclip 3
lRatchet wheel 4
lSpring 5
lPlain washer 6
lCirclip 7
To kick axle 8.
NOTE:
lApply the molybdenum disulfide oil on the
kick gear inner circumference.
lAlign the punch mark a on the ratchet wheel
with the punch mark b on the kick axle.
New
New
2. Install:
lTorsion spring 1
To kick axle 2.
NOTE:
Make sure the stopper a of the torsion spring
fits into the hole b on the kick axle.

4 - 74
ENGCDI MAGNETO
EC4L3000
REMOVAL POINTS
EC4L3101
Rotor
1. Remove:
lNut (rotor) 1
lPlain washer
Use the rotor holding tool 2.
2. Remove:
lRotor 1
Use the flywheel puller 2.
NOTE:
When installing the flywheel puller, turn it
counterclockwise.
Rotor holding tool:
YU-1235/90890-01235
Flywheel puller:
YM-1189/90890-01189
EC4L4000
INSPECTION
EC4L4101
CDI magneto
1. Inspect:
lRotor inner surface a
lStator outer surface b
Damage ® Inspect the crankshaft
runout and crankshaft bearing.
If necessary, replace CDI magneto and/
or stator.
EC4L4200
Woodruff key
1. Inspect:
lWoodruff key 1
Damage ® Replace.

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)