2005 YAMAHA YZ250F oil

5 - 8
CHAS
4. Install:
Collar 1
NOTE:
Apply the lithium soap base grease on the oil
seal lip.
FRONT WHEEL AND REAR WHEEL
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:
Left drive chain puller 1
Wheel axle 2
NOTE:
Install the left drive chain puller, and insert
the wheel axle from left side.
Apply the lithium soap base grease on the
wheel axle.
8. Install:
Right drive chain puller 1
Washer 2
Nut (wheel axle) 3
NOTE:
Temporarily tighten the nut (wheel axle) at this
point.

5 - 24
CHASFRONT BRAKE AND REAR BRAKE
2. Install:
Brake hose holder 1
Screw (brake hose holder) 2
CAUTION:
After installing the brake hose holders,
make sure the brake hose does not contact
the spring (rear shock absorber). If it does,
correct its twist.
Brake fluid
1. Fill:
Brake fluid
Until the fluid level reaches “LOWER”
level line a.
WARNING
Use only the designated quality brake
fluid:
otherwise, the rubber seals may deterio-
rate, causing leakage and poor brake per-
formance.
Refill with the same type of brake fluid;
mixing fluids may result in a harmful
chemical reaction and lead to poor perfor-
mance.
Be careful that water does not enter the
master cylinder when refilling. Water will
significantly lower the boiling point of the
fluid and may result in vapor lock.
CAUTION:
Brake fluid may erode painted surfaces or
plastic parts. Always clean up spilled fluid
immediately.
È
Front
ÉRear
Recommended brake fluid:
DOT #4
T R..1 Nm (0.1 m · kg, 0.7 ft · lb)
È
É

5 - 27
CHASFRONT FORK
EC558000
FRONT FORK DISASSEMBLY
Extent of removal:
1 Oil seal removal
2 Damper assembly removal
Extent of removal Order Part name Q’ty Remarks
FRONT FORK DISASSEMBLY
1Adjuster 1 Drain the fork oil. Use special tool.
Refer to “REMOVAL POINTS”.
2Fork spring 1
3Dust seal 1
Refer to “REMOVAL POINTS”.
4Stopper ring 1
5Inner tube 1
6Outer tube 1
7Piston metal 1
8Slide metal 1
9Oil seal washer 1
0Oil seal 1
ABase valve 1
Drain the fork oil. Use special tool.
Refer to “REMOVAL POINTS”.
BDamper assembly 1
1
2

5 - 28
CHASFRONT FORK
EC556000
HANDLING NOTE
NOTE:
The front fork requires careful attention. So it is
recommended that the front fork be maintained
at the dealers.
CAUTION:
To prevent an accidental explosion of air,
the following instructions should be
observed:
The front fork with a built-in piston rod
has a very sophisticated internal con-
struction and is particularly sensitive to
foreign material.
Use enough care not to allow any foreign
material to come in when the oil is
replaced or when the front fork is disas-
sembled and reassembled.
Before removing the base valves or front
forks, be sure to extract the air from the
air chamber completely.
EC553000
REMOVAL POINTS
Damper assembly
1. Loosen:
Damper assembly 1
NOTE:
Before removing the front fork from the
machine, loosen the damper assembly with
the cap bolt ring wrench 2.
Cap bolt ring wrench:
YM-01501/90890-01501

5 - 29
CHASFRONT FORK
Adjuster
1. Drain the outer tube of its front fork oil at its
top.
2. Loosen:
Adjuster 1
3. Remove:
Adjuster 1
NOTE:
While compressing the inner tube 2, set the
cap bolt ring wrench 4 between the inner
tube and locknut 3.
Hold the locknut and remove the adjuster.
CAUTION:
Do not remove the locknut as it may go into
the damper assembly and not be taken out.
Cap bolt ring wrench:
YM-01501/90890-01501
EC553201
Inner tube
1. Remove:
Dust seal 1
Stopper ring 2
Using slotted-head screwdriver.
CAUTION:
Take care not to scratch the inner tube.
2. Remove:
Inner tube 1
Oil seal removal steps:
Push in slowly a the inner tube just before
it bottoms out and then pull it back quickly
b.
Repeat this step until the inner tube can
be pulled out from the outer tube.

5 - 30
CHAS
Base valve
1. Remove:
Base valve 1
From damper assembly 2.
NOTE:
Hold the damper assembly with the cap bolt
ring wrench 3 and use the cap bolt wrench 4
to remove the base valve.
Cap bolt wrench:
YM-01500/90890-01500
Cap bolt ring wrench:
YM-01501/90890-01501
EC554000
INSPECTION
Damper assembly
1. Inspect:
Damper assembly 1
Bend/damage → Replace.
O-ring 2
Wear/damage → Replace.
CAUTION:
The front fork with a built-in piston rod has
a very sophisticated internal construction
and is particularly sensitive to foreign
material.
Use enough care not to allow any foreign
material to come in when the oil is replaced
or when the front fork is disassembled and
reassembled.
FRONT FORK

5 - 31
CHAS
Base valve
1. Inspect:
Base valve 1
Wear/damage → Replace.
Contamination → Clean.
O-ring 2
Wear/damage → Replace.
Bushing 3
Wear/damage → Replace base valve.
Spring 4
Damage/fatigue → Replace base valve.
Air bleed screw 5
Wear/damage → Replace base valve.
EC554400
Fork spring
1. Measure:
Fork spring free length a
Out of specification → Replace.
EC554502
Inner tube
1. Inspect:
Inner tube surface a
Score marks → Repair or replace.
Use #1,000 grit wet sandpaper.
Damaged oil lock piece → Replace.
Inner tube 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 inner
tube as this may dangerously weaken the
tube.
Fork spring free length:
465 mm (18.3 in)
: 460 mm (18.1 in)
Inner tube bending limit:
0.2 mm (0.008 in)
FRONT FORK

5 - 32
CHAS
EC554600
Outer tube
1. Inspect:
Outer tube 1
Score marks/wear/damage → Replace.
Adjuster
1. Inspect:
Adjuster 1
O-ring 2
Wear/damage → Replace.
EC555000
ASSEMBLY AND INSTALLATION
Front fork assembly
1. Wash the all parts in a clean solvent.
2. Stretch the damper assembly fully.
3. Fill:
Front fork oil 1
To damper assembly.
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 “S1”
Oil capacity:
195 cm
3 (6.86 Imp oz, 6.59 US oz)
FRONT FORK