wheel YAMAHA YZ426F 2002 Owner's Guide

5 - 4
CHAS

FRONT WHEEL AND REAR WHEEL
EC514200
Wheel axle
1. Measure:

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)
EC594200
Brake disc
1. Measure:

Brake 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:

Brake 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
CHAS

FRONT WHEEL AND REAR WHEEL
EC595000
ASSEMBLY AND INSTALLATION
EC595100
Front wheel
1. Install:

Bearing (left)
1


Spacer
2


Bearing (right)
3


Oil seal
4

NOTE:


Apply the lithium soap base grease on the
bearing and oil seal lip when installing.

Use a socket that matches the outside diam-
eter of the race of the bearing.

Left side of bearing shall be installed first.

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:
Brake disc 1
Bolt (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:
Collar 1
NOTE:
Apply the lithium soap base grease on the oil
seal lip.
Install the collars with their projections a
facing the wheel.
4. Install:
Wheel
NOTE:
Install the brake disc 1 between the brake
pads 2 correctly.

5 - 6
CHASFRONT WHEEL AND REAR WHEEL
5. Install:
Wheel axle 1
NOTE:
Apply the lithium soap base grease on the
wheel axle.
6. Install:
Nut (wheel axle) 1
T R..105 Nm (10.5 m · kg, 75 ft · lb)
7. Tighten:
Bolt (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:
Brake 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)

5 - 7
CHASFRONT WHEEL AND REAR WHEEL
9. Install:
Hose cover 1
Plain washer 2
Bolt [hose cover (M8)] 3
Bolt [hose cover (M6)] 4
T R..16 Nm (1.6 m · kg, 11 ft · lb)
T R..7 Nm (0.7 m · kg, 5.1 ft · lb)
EC5251A0
Rear wheel
1. Install:
Bearing (right) 1
Circlip 2
Spacer 3
Bearing (left) 4
Oil seal 5
NOTE:
Apply the lithium soap base grease on the
bearing and oil seal lip when installing.
Install the bearing with seal facing outward.
Use a socket that matches the outside diam-
eter of the race of the bearing.
Right side of bearing shall be installed first.
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.
New
New
2. Install:
Brake disc 1
Bolt (brake disc) 2
NOTE:
Tighten the bolts in stage, using a crisscross
pattern.
T R..14 Nm (1.4 m · kg, 10 ft · lb)

5 - 8
CHAS
3. Install:
Driven sprocket 1
Bolt (driven sprocket) 2
Plain washer (driven sprocket) 3
Nut (driven sprocket) 4
NOTE:
Tighten the nuts in stage, using a crisscross
pattern.
T R..42 Nm (4.2 m · kg, 30 ft · lb)
FRONT WHEEL AND REAR WHEEL
4. Install:
Collar 1
NOTE:
Apply the lithium soap base grease on the oil
seal lip.
5. Install:
Wheel
NOTE:
Install the brake disc 1 between the brake
pads 2 correctly.
6. Install:
Drive chain 1
NOTE:
Push the wheel 2 forward and install the drive
chain.
7. Install:
Chain puller (left) 1
Wheel axle 2
NOTE:
Install the chain puller (left), and insert the
wheel axle from left side.
Apply the lithium soap base grease on the
wheel axle.

5 - 9
CHASFRONT WHEEL AND REAR WHEEL
8. Install:
Chain puller (right) 1
Plain washer 2
Nut (wheel axle) 3
NOTE:
Temporarily tighten the nut (wheel axle) at this
point.
9. Adjust:
Drive chain slack a
Refer to “DRIVE CHAIN SLACK
ADJUSTMENT” section in the CHAP-
TER 3.
Drive chain slack:
40 ~ 50 mm (1.6 ~ 2.0 in)
10. Tighten:
Nut (wheel axle) 1
Locknut 2
T R..125 Nm (12.5 m · kg, 90 ft · lb)

5 - 11
CHAS
EC5A8100
REAR BRAKE
Extent of removal:1 Caliper removal2 Brake hose removal
3 Master cylinder removal
Extent of removal Order Part name Q’ty Remarks
Preparation for removalREAR BRAKE 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.
Rear wheel Refer to “FRONT WHEEL AND REAR
WHEEL” section.
Drain the brake fluid. Refer to “REMOVAL POINTS”.
1 Pad pin plug 1 Remove when loosening the pad pin.
2 Pad pin 1 Loosen when disassembling the caliper.
3 Caliper 1
4 Brake hose holder 2
5 Union bolt 2
6 Brake hose 1
7 Brake pedal 1
8 Reservoir tank 1
9 Reservoir hose 1
10Master cylinder
1
3
1
321
FRONT BRAKE AND REAR BRAKE

5 - 19
CHASFRONT BRAKE AND REAR BRAKE
2. Install:
Disc cover 1
Bolt (disc cover) 2
T R..7 Nm (0.7 m · kg, 5.1 ft · lb)
3. Install:
Copper washer 1
Brake hose 2
Union bolt 3
WARNING
Always use new copper washers.
ACHTUNG:CAUTION:
Install the brake hose to the caliper with the
paint a on the pipe facing the caliper and
with the pipe contacting the caliper projec-
tion b.
New
T R..30 Nm (3.0 m · kg, 22 ft · lb)
4. Install:
Caliper 1
Rear wheel 2
Refer to “FRONT WHEEL AND REAR
WHEEL” section.
5. Tighten:
Pad pin 3
6. Install:
Pad pin plug 4
T R..18 Nm (1.8 m · kg, 13 ft · lb)
T R..3 Nm (0.3 m · kg, 2.2 ft · lb)

5 - 23
CHASFRONT BRAKE AND REAR BRAKE
4. Install:
Pin 1
Plain washer 2
Cotter pin 3
NOTE:
After installing, check the brake pedal height.
Refer to “REAR BRAKE ADJUSTMENT” sec-
tion in the CHAPTER 3.
New
Front brake hose
1. Install:
Brake 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..10 Nm (1.0 m · kg, 7.2 ft · lb)
2. Install:
Hose cover 1
Plain washer 2
Bolt [hose cover (M8)] 3
Bolt [hose cover (M6)] 4
T R..16 Nm (1.6 m · kg, 11 ft · lb)
T R..7 Nm (0.7 m · kg, 5.1 ft · lb)
3. Pass the brake hose through the cable
guide 1, then through the guide a on
the protector 2.

5 - 27
CHASFRONT FORK
EC550000
FRONT FORK
Extent of removal:1 Front fork removal
Extent of removal Order Part name Q’ty Remarks
Preparation for removalFRONT FORK 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.
Front wheel Refer to “FRONT WHEEL AND REAR
WHEEL” section.
Front caliper Refer to “FRONT BRAKE AND REAR
BRAKE” section.
Number plate
Handlebar Refer to “HANDLEBAR” section.
1 Protector 1
2 Brake hose holder 2
3 Pinch bolt (handle crown) 2 Only loosening.
4 Cap bolt 1Loosen when disassembling the front fork.
5 Pinch bolt (under bracket) 2 Only loosening.
6 Front fork 1
1