2002 YAMAHA YZ426F oil

5 - 35
CHASFRONT FORK
13. Check:
Inner tube smooth movement
Tightness/binding/rough spots →
Repeat the steps 2 to 12.
14. Compress the front fork fully.
15. Fill:
Front fork oil
Until outer tube top surface with recom-
mended fork oil 1.
ACHTUNG:CAUTION:
Be sure to use recommended fork oil. If
other oils are used, they may have an
excessively adverse effect on the front
fork performance.
Never allow foreign materials to enter the
front fork.
Recommended oil:
Suspension oil “01”
16. After filling, pump the damper rod 1
slowly up and down more than 10 times
to distribute the fork oil.
17. Fill:
Front fork oil
Until outer tube top surface with recom-
mended fork oil once more.
18. After filling, pump the outer tube 1 slowly
up and down (about 200 mm (7.9 in)
stroke) to distribute the fork oil once
more.
NOTE:
Be careful not to excessive full stroke. A stroke
of 200 mm (7.9 in) or more will cause air to
enter. In this case, repeat the steps 15 to 18.

5 - 36
CHASFRONT FORK
19. Wait ten minutes until the air bubbles
have been removed from the front fork,
and the oil has dispense evenly in system
before setting recommended oil level.
NOTE:
Fill with the fork oil up to the top end of the
outer tube, or the fork oil will not spread over to
every part of the front forks, thus making it
impossible to obtain the correct level.
Be sure to fill with the fork oil up to the top of
the outer tube and bleed the front forks.
20. Measure:
Oil level (left and right) a
Out of specification → Adjust.
NOTE:
Be sure to install the spring guide 2 when
checking the oil level.
WARNING
Never fail to make the oil level adjustment
between the maximum and minimum level
and always adjust each front fork to the
same setting. Uneven adjustment can
cause poor handling and loss of stability.
Standard oil level:
135 mm (5.31 in)
Extent of adjustment:
80 ~ 150 mm (3.15 ~ 5.91 in)
From top of outer tube with
inner tube and damper rod 1
fully compressed without
spring.

5 - 42
CHASHANDLEBAR
EC5B5000
ASSEMBLY AND INSTALLATION
Handlebar
1. Install:
Handlebar 1
Handlebar holder 2
Bolt (handlebar holder) 3
NOTE:
The upper handlebar holder should be
installed with the punched mark a forward.
First tighten the bolts on the front side of the
handlebar holder, and then tighten the bolts
on the rear side.
2. Install:
Grip (left) 1
Apply the adhesive to the handlebar 2.
NOTE:
Before applying the adhesive, wipe off
grease or oil on the handlebar surface a
with a lacquer thinner.
Install the grip (left) to the handlebar so that
the line b between the two arrow marks
faces straight upward.
T R..28 Nm (2.8 m · kg, 20 ft · lb)
3. Install:
Grip (right) 1
Collar 2
Apply the adhesive on the tube guide
3.
NOTE:
Before applying the adhesive, wipe off
grease or oil on the tube guide surface a
with a lacquer thinner.
Install the grip to the tube guide so that the
grip match mark b and tube guide slot c
form the angle as shown.
R
L
90˚
3 1b
c

5 - 52
CHASSWINGARM
EC578000
SWINGARM DISASSEMBLY
Extent of removal:1 Swingarm disassembly2 Connecting rod removal and disassembly
3 Relay arm removal and disassembly
Extent of removal Order Part name Q’ty Remarks
SWINGARM DISASSEMBLY
1 Cap 2
2 Relay arm 1
3 Connecting rod 1
4 Collar 2
5 Oil seal 2
6 Thrust bearing 2
7 Bush 2
8 Oil seal 8
9 Bearing 8 Refer to “REMOVAL POINTS”.
1
2
32
3

5 - 53
CHASSWINGARM
EC573000
REMOVAL POINTS
EC573200
Bearing
1. Remove:
Bearing 1
NOTE:
Install the bearing by pressing its outer race.
EC574010
INSPECTION
Wash the bearings, bushes, collars, and cov-
ers in a solvent.
EC574111
Swingarm
1. Inspect:
Bearing 1
Bush 2
Free play exists/unsmooth revolution/
rust → Replace bearing and bush as a
set.
2. Inspect:
Oil seal 3
Damage → Replace.
EC574210
Relay arm
1. Inspect:
Bearing 1
Collar 2
Free play exists/unsmooth revolution/rust
→ Replace bearing and collar as a set.
2. Inspect:
Oil seal 3
Damage → Replace.
EC574310
Connecting rod
1. Inspect:
Bearing 1
Collar 2
Free play exists/unsmooth revolution/rust
→ Replace bearing and collar as a set.
2. Inspect:
Oil seal 3
Damage → Replace.

5 - 54
CHASSWINGARM
EC575000
ASSEMBLY AND INSTALLATION
EC575201
Bearing and oil seal
1. Install:
Bearing 1
Oil seal 2
To swingarm.
NOTE:
Apply the molybdenum disulfide grease on
the bearing when installing.
Install the bearing by pressing it on the side
having the manufacture’s marks or numbers.
First install the outer and then the inner bear-
ings to a specified depth from inside.
Installed depth of bearings:
Outer a: Zero mm (Zero in)
Inner b: 8.5 mm (0.33 in)
2. Install:
Bearing 1
Oil seal 2
To relay arm.
NOTE:
Apply the molybdenum disulfide grease on
the bearing when installing.
Install the bearing by pressing it on the side
having the manufacture’s marks or numbers.
3. Install:
Bearing 1
Oil seal 2
To connecting rod.
NOTE:
Apply the molybdenum disulfide grease on
the bearing when installing.
Install the bearing by pressing it on the side
having the manufacture’s marks or numbers.
Installed depth of bearings a:
5 mm (0.20 in)
Installed depth of bearings a:
5 mm (0.20 in)

5 - 55
CHASSWINGARM
EC5751B1
Swingarm
1. Install:
Bush 1
Thrust bearing 2
Oil seal 3
Collar 4
To swingarm 5.
NOTE:
Apply the molybdenum disulfide grease on the
bushes, thrust bearings and oil seal lips.
2. Install:
Collar 1
To relay arm 2.
NOTE:
Apply the molybdenum disulfide grease on the
collars, bearings and oil seal lips.
3. Install:
Collar 1
To connecting rod 2.
NOTE:
Apply the molybdenum disulfide grease on the
collar, bearings and oil seal lips.
4. Install:
Connecting rod 1
Bolt (connecting rod) 2
Plain washer 3
Nut (connecting rod) 4
To relay arm 5.
NOTE:
Apply the molybdenum disulfide grease on the
bolt.
T R..80 Nm (8.0 m · kg, 58 ft · lb)

5 - 60
CHAS
EC586000
HANDLING NOTE
WARNING
This shock absorber is provided with a
separate type tank filled with high-pressure
nitrogen gas. To prevent the danger of
explosion, read and understand the follow-
ing information before handling the shock
absorber.
The manufacturer can not be held respon-
sible for property damage or personal
injury that may result from improper han-
dling.
1. Never tamper or attempt to disassem-
ble the cylinder or the tank.
2. Never throw the shock absorber into
an open flame or other high heat. The
shock absorber may explode as a
result of nitrogen gas expansion and/
or damage to the hose.
3. Be careful not to damage any part of
the gas tank. A damaged gas tank will
impair the damping performance or
cause a malfunction.
4. Take care not to scratch the contact
surface of the piston rod with the cylin-
der; or oil could leak out.
5. Never attempt to remove the plug at
the bottom of the nitrogen gas tank. It
is very dangerous to remove the plug.
6. When scrapping the shock absorber,
follow the instructions on disposal.
EC587000
NOTES ON DISPOSAL (YAMAHA DEALERS
ONLY)
Before disposing the shock absorber, be sure
to extract the nitrogen gas from valve 1. Wear
eye protection to prevent eye damage from
escaping gas and/or metal chips.
WARNING
To dispose of a damaged or worn-out
shock absorber, take the unit to your
Yamaha dealer for this disposal procedure.
REAR SHOCK ABSORBER