2010 YAMAHA YZ250F oil

5-3
FRONT WHEEL AND REAR WHEEL
HANDLING NOTE
Support the machine securely so
there is no danger of it falling over.
REMOVING THE REAR WHEEL
1. Remove:• Wheel "1"
Push the wheel forward and remove
the drive chain "2".
REMOVING THE WHEEL BEARING
1. Remove:• Bearing "1"
Remove the bearing using a general
bearing puller "2".
CHECKING THE WHEEL
1. Measure:• Wheel runout
Out of limit → Repair/replace.
2. Inspect: • BearingRotate inner race with a finger.
Rough spot/seizure → Replace.
Replace the bearings, oil seal and
wheel collar as a set.
CHECKING THE WHEEL AXLE
1. Measure:
• Wheel axle bendsOut of specification → Replace.
Use the dial gauge "1".
The bending value is shown by one
half of the dial gauge reading.
Do not attempt to straighten a bent
axle.
CHECKING THE 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 condi-
tion, replace the brake disc.
2. Measure: • Brake disc thickness "a"
Out of limit → Replace. INSTALLING THE FRONT WHEEL
1. Install:
• Bearing (left) "1"
• Spacer "2"
• Bearing (right) "3"
• Oil seal "4"
• Apply the lithium soap base grease on the bearing and oil seal lip when
installing.
• Use a socket that matches the out-
side diameter of the race of the
bearing.
• Left side of bearing shall be in- stalled first.
• Install the oil seal with its manufac-
ture's marks or numbers facing out-
ward.
Do not strike the inner race of the
bearing. Contact should be made
only with the outer race.
Wheel runout limit: Radial "1": 2.0 mm
(0.08 in)
Lateral "2": 2.0 mm
(0.08 in)
Wheel axle bending limit:
0.5 mm (0.020 in)
Brake disc deflection lim-
it: Rear:
: 0.15 mm
(0.006 in)
Brake disc thickness: 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)

5-4
FRONT WHEEL AND REAR WHEEL
2. Install:• Brake disc "1"
• Bolt (brake disc) "2"
Tighten the bolts in stage, using a
crisscross pattern.
3. Install:•Collar "1"
• Apply the lithium soap base grease on the oil seal lip.
• Install the collars with their projec-
tions "a" facing the wheel.
4. Install:• Wheel
Install the brake disc "1" between the
brake pads "2" correctly.
5. Install:• Wheel axle "1"
Apply the lithium soap base grease
on the wheel axle.
6. Install:• Nut (wheel axle) "1"
7. Tighten: • Bolt (axle holder) "1"
Before tightening the bolt, fit the
wheel axle to the axle holder by strok-
ing the front fork several times with
the front brake applied.
INSTALLING THE REAR WHEEL
1. Install:• Bearing (right) "1"
• Circlip "2"
• Spacer "3"
• Bearing (left) "4"
• Oil seal "5"
• 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 out- side diameter of the race of the
bearing.
• Right side of bearing shall be in- stalled first.
• Install the oil seal with its manufac- ture's marks or numbers facing out-
ward.
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"
Tighten the bolts in stage, using a
crisscross pattern.
3. Install:
• Rear wheel sprocket "1"
• Bolt (rear wheel sprocket) "2"
• Washer (rear wheel sprocket) "3"
• Nut (rear wheel sprocket) "4"
Tighten the nuts in stage, using a
crisscross pattern.
Bolt (brake disc): 12 Nm (1.2 m•kg, 8.7
ft•lb)
Nut (wheel axle):105 Nm (10.5 m•kg, 75
ft•lb)
Bolt (axle holder): 21 Nm (2.1 m•kg, 15
ft•lb)
Bolt (brake disc): 14 Nm (1.4 m•kg, 10
ft•lb)
Nut (rear wheel sprock-
et): 42 Nm (4.2 m•kg, 30
ft•lb)

5-5
FRONT WHEEL AND REAR WHEEL
4. Install:•Collar "1"
Apply the lithium soap base grease
on the oil seal lip.
5. Install:• Wheel
Install the brake disc "1" between the
brake pads "2" correctly.
6. Install:• Drive chain "1"
Push the wheel "2" forward and install
the drive chain.
7. Install:• Left drive chain puller "1"
• Wheel axle "2"
• 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"
Temporarily tighten the nut (wheel
axle) at this point.
9. Adjust:• Drive chain slack "a"
Refer to "ADJUSTING THE
DRIVE CHAIN SLACK" section in
the CHAPTER 3.
10. Tighten: • Nut (wheel axle) "1"
• Locknut "2"
Drive chain slack: 50–60 mm (2.0–2.4 in)
Nut (wheel axle): 135 Nm (13.5 m•kg, 98
ft•lb)
Locknut: 21 Nm (2.1 m•kg, 15
ft•lb)

5-14
FRONT BRAKE AND REAR BRAKE
Install the brake hose so that its
pipe portion "a" directs as shown
and lightly touches the projection
"b" on the brake caliper.
2. Install:• Brake hose holder "1"
• Bolt (brake hose holder) "2"
Align the top "a" of the brake hose
holder with the paint "b" of the brake
hose.
3. Pass the brake hose through the cable guide "1".
4. Install: • Copper washer "1"
• Brake hose "2"
• Union bolt "3"
Always use new copper washers.
Install the brake hose so that its
pipe portion "a" directs as shown
and lightly touches the projection
"b" on the brake master cylinder.
INSTALLING THE REAR BRAKE
HOSE
1. Install:• Copper washer "1"
• Brake hose "2"
• Union bolt "3"
Always use new copper washers.
Install the brake hose so that its
pipe portion "a" directs as shown
and lightly touches the projection
"b" on the brake caliper.
2. Install:• Brake hose holder "1"
• Screw (brake hose holder) "2"
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.
FILLING THE BRAKE FLUID
1. Fill:• Brake fluid
Until the fluid level reaches
"LOWER" level line "a".
• Use only the designated quality brake fluid:
otherwise, the rubber seals may
deteriorate, causi ng leakage and
poor brake performance.
• Refill with the same type of brake
fluid;
mixing fluids may result in a
harmful chemical reaction and
lead to poor performance.
• Be careful that water does not enter the master cylinder when
refilling. Water will significantly
lower the boiling point of the flu-
id and may result in vapor lock.
Brake fluid may erode painted sur-
faces or plastic parts. Always
clean up spilled fluid immediately.
Bolt (brake hose holder):
8 Nm (0.8 m•kg, 5.8 ft
•lb)
Union bolt: 30 Nm (3.0 m•kg, 22
ft•lb)
Union bolt:
30 Nm (3.0 m•kg, 22
ft•lb)
Screw (brake hose hold-
er): 3 Nm (0.3 m•kg, 2.2
ft•lb)
Recommended brake flu-
id:
DOT #4

5-17
FRONT FORK
DISASSEMBLING THE FRONT FORKOrder Part name Q'ty Remarks1 Adjuster 1 Drain the fork oil. Refer to removal section.
2 Fork spring 1
3 Dust seal 1 Refer to removal section.
4 Stopper ring 1 Refer to removal section.
5 Inner tube 1 Refer to removal section.
6 Outer tube 1
7 Piston metal 1
8 Slide metal 1
9 Oil seal washer 1
10 Oil seal 1
11 Base valve 1 Drain the fork o il. Refer to removal section.
12 Damper assembly 1 Drain the fork oil. Refer to removal section.
30 Nm (3.0 m kg, 22 ft lb)
29 Nm (2.9 m kg, 21 ft lb)
29 Nm (2.9 m kg, 21 ft lb)
1 Nm (0.1 m kg, 0.7 ft lb)
55 Nm (5.5 m kg, 40 ft lb)

5-18
FRONT FORK
HANDLING NOTE
Support the machine securely so
there is no danger of it falling over.
The front fork requires careful atten-
tion. So it is recommended that the
front fork be maintained at the deal-
ers.
To prevent an accidental explosion
of air, the following instructions
should be observed:
• The front fork with a built-in pis-ton rod has a very sophisticated
internal construction and is par-
ticularly sensitive to foreign ma-
terial. 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 com-
pletely.
REMOVING THE DAMPER
ASSEMBLY
1. Loosen:
• Damper assembly "1"
Before removing the front fork from
the machine, loosen the damper as-
sembly with the cap bolt ring wrench
"2".
REMOVING THE ADJUSTER
1. Drain the outer tube of its front fork oil at its top.
2. Loosen:
•Adjuster "1"
3. Remove: •Adjuster "1"
• 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.
Do not remove the locknut as the
damper rod may go into the damp-
er assembly and not be taken out.
REMOVING THE INNER TUBE
1. Remove:• Dust seal "1"
• Stopper ring "2"Using slotted-head screwdriver.
Take care not to scratch the inner
tube.
2. Remove:
• Inner tube "1"
Oil seal removal steps:
a. Push in slowly "a" the inner tube just before it bottoms out and then
pull it back quickly "b".
b. Repeat this step until the inner tube can be pulled out from the
outer tube.
REMOVING THE BASE VALVE
1. Remove:• Base valve "1"From damper assembly "2".
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 ring wrench:
YM-01501/90890-01501
Cap bolt ring wrench:YM-01501/90890-01501
Cap bolt wrench: YM-01500/90890-01500
Cap bolt ring wrench: YM-01501/90890-01501

5-19
FRONT FORK
CHECKING THE DAMPER
ASSEMBLY
1. Inspect:• Damper assembly "1"
Bend/damage → Replace.
• O-ring "2" Wear/damage → Replace.
The front fork with a built-in piston
rod has a very sophisticated inter-
nal 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 re-
assembled.
CHECKING THE BASE VALVE
1. Inspect: • Base valve "1"
Wear/damage →Replace.
Contamination →Clean.
• O-ring "2"
Wear/damage →Replace.
• Piston metal "3" Wear/damage →Replace.
• Spring "4" Damage/fatigue →Replace base
valve.
• Air bleed screw "5" Wear/damage →Replace.
CHECKING THE COLLAR
1. Inspect: • Piston metal "1"Wear/damage →Replace. CHECKING THE FORK SPRING
1. Measure:
• Fork spring free length "a"Out of specification →Replace.
CHECKING THE INNER TUBE
1. Inspect: • Inner tube surface "a"Score marks →Repair or replace.
Use #1,000 grit wet sandpaper.
Damaged oil lock piece →Re-
place.
• Inner tube bends Out of specification →Replace.
Use the dial gauge "1".
The bending value is shown by one
half of the dial gauge reading.
Do not attempt to straighten a bent
inner tube as this may dangerous-
ly weaken the tube.
CHECKING THE OUTER TUBE
1. Inspect:
• Outer tube "1"Score marks/wear/damage →Re-
place. CHECKING THE ADJUSTER
1. Inspect:
•Adjuster "1"
• O-ring "2"
Wear/damage →Replace.
ASSEMBLING THE FRONT FORK
1. Wash the all parts in a clean sol- vent.
2. Stretch the damper assembly ful- ly.
3. Fill:
• Front fork oil "1"To damper assembly.
• Be sure to use recommended fork oil. If other oils are used,
they may have an excessively ad-
verse effect on the front fork per-
formance.
• Never allow foreign materials to
enter the front fork.
4. After filling, pump the damper as- sembly "1" slowly up and down
(about 200 mm (7.9 in) stroke)
several times to bleed the damper
assembly of air.
Be careful not to ex cessive full stroke.
A stroke of 200 mm (7.9 in) or more
will cause air to enter. In this case, re-
peat the steps 2 to 4.
Fork spring free length: 454 mm (17.9 in)
: 449 mm (17.7
in)
Inner tube bending limit: 0.2 mm (0.008 in)
Recommended oil: Suspension oil "S1"
Oil capacity: 199 cm
3 (7.00 Imp oz,
6.73 US oz)

5-20
FRONT FORK
5. Measure:• Oil level (left and right) "a"Out of specification → Adjust.
6. Tighten: • Locknut "1"
Fully finger tighten the locknut onto
the damper assembly.
7. Loosen:• Compression damping adjuster "1"
• Loosen the compression damping
adjuster finger tight.
• Record the set position of the ad- juster (the amount of turning out the
fully turned in position).
8. Install:
• Base valve "1"To damper assembly "2".
First bring the damper rod pressure to
a maximum. Then install the base
valve while releasing the damper rod
pressure.
9. Check:
• Damper assemblyNot fully stretched → Repeat the
steps 2 to 8.
10. Tighten: • Base valve "1"
Hold the damper assembly with the
cap bolt ring wrench "2" and use the
cap bolt wrench "3" to tighten the
base valve with specified torque.
11. After filling, pump the damper as-
sembly "1" slowly up and down
more than 10 times to distribute
the fork oil. 12. While protecting the damper as-
sembly "1" with a rag and com-
pressing fully, al low excessive oil
to overflow on the base valve
side.
Take care not to damage the damp-
er assembly.
13. Allow the overflowing oil to es- cape at the hole "a" in the damper
assembly.
14. Check: • Damper assembly smooth move-ment
Tightness/binding/rough spots →
Repeat the steps 2 to 13.
15. Install: • Dust seal "1"
• Stopper ring "2"
• Oil seal "3"
• Oil seal washer "4"
• Slide metal "5" To inner tube "6".
• Apply the fork oil on the inner tube.
• When installing the oil seal, use vi-nyl seat "a" with fork oil applied to
protect the oil seal lip.
• Install the oil seal with its manufac-
ture's marks or number facing the
axle holder side.
Standard oil level: 145-148 mm (5.71-5.83
in)
From top of fully
stretched damper as-
sembly.
Base valve:29 Nm (2.9 m•kg, 21 ft•
lb)
Cap bolt wrench: YM-01500/90890-01500
Cap bolt ring wrench:
YM-01501/90890-01501