oil YAMAHA WR 250F 2011 Manual Online

6-2
FRONT WHEEL AND REAR WHEEL
REMOVING THE REAR WHEEL
Order Part name Q'ty Remarks
Hold the machine by placing the suitable stand
under the engine.Refer to "HANDLING NOTE".
1 Nut (rear wheel axle) 1
2 Rear wheel axle 1
3 Drive chain puller 2
4 Rear wheel 1 Refer to removal section.
5 Collar 2
6 Rear wheel sprocket 1
7 Oil seal 2
8 Circlip 1
9 Bearing 2 Refer to removal section.
10 Brake disc 1
125 Nm (12.5 m kg, 90 ft lb)
14 Nm (1.4 m kg, 10 ft lb)
19 Nm (1.9 m kg, 13 ft lb)
19 Nm (1.9 m kg, 13 ft lb)
50 Nm (5.0 m kg, 36 ft lb)
6

6-3
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:
• Bearing
Rotate 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 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
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)

6-4
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.
4. Install:
• Speed sensor "1"
• Apply the lithium soap base grease
on the oil seal lip of the speed sen-
sor.
• Make sure the two projections "a" in
the wheel hub are meshed with the
two slots "b" in the speed sensor.
5. Install:
• Wheel
• Install the brake disc "1" between
the brake pads "2" correctly.
• Make sure that the projections "a" in
the speed sensor fits over the stop-
per "b" on the front fork inner tube.
6. Install:
• Wheel axle "1"
Apply the lithium soap base grease
on the wheel axle.
7. Install:
• Nut (wheel axle) "1"
8. 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.
Bolt (brake disc):
12 Nm (1.2 m•kg, 8.7
ft•lb)
Nut (wheel axle):
90 Nm (9.0 m•kg, 65
ft•lb)
Bolt (axle holder):
21 Nm (2.1 m•kg, 15
ft•lb)

6-5
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:
• 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.
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" Bolt (brake disc):
14 Nm (1.4 m•kg, 10
ft•lb)
Nut (rear wheel sprock-
et):
50 Nm (5.0 m•kg, 36
ft•lb)
Drive chain slack:
48–58 mm (1.9–2.3 in)
Nut (wheel axle):
125 Nm (12.5 m•kg, 90
ft•lb)
Locknut:
19 Nm (1.9 m•kg, 13
ft•lb)

6-15
FRONT BRAKE AND REAR BRAKE
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, causing 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.
A. Front
B. Rear
2. Air bleed:
• Brake system
Refer to "BLEEDING THE HY-
DRAULIC BRAKE SYSTEM" sec-
tion in the CHAPTER 3.
3. Inspect:
• Brake fluid level
Fluid at lower level→Fill up.
Refer to "CHECKING THE
BRAKE FLUID LEVEL" section in
the CHAPTER 3.4. Install:
• Reservoir float (front brake)
• Diaphragm
• Brake master cylinder cap "1"
• Screw (bolt) {brake master cylin-
der cap} "2"
After installation, while pulling the
brake lever in or pushing down on
the brake pedal, check whether
there is any brake fluid leaking
where the union bolts are installed
respectively at the brake master
cylinder and brake caliper.
A. Front
B. Rear
5. Install: (rear brake only)
• Protector "1"
• Bolt (protector) "2" Recommended brake flu-
id:
DOT #4
Screw (bolt) {brake mas-
ter cylinder cap}:
2 Nm (0.2 m•kg, 1.4
ft•lb)
Bolt (protector):
7 Nm (0.7 m•kg, 5.1
ft•lb)

6-17
FRONT FORK
DISASSEMBLING THE FRONT FORK
Order Part name Q'ty Remarks
1 Front fork cap bolt 1 Refer to removal section.
2 Fork spring 1 Drain the fork oil.
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 Spring guide 1
12 Base valve 1 Refer to removal section.
13 Damper rod 1 Refer to removal section.

6-18
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 cap bolts or
front forks, be sure to extract the
air from the air chamber com-
pletely.
REMOVING THE FRONT FORK
CAP BOLT
1. Remove:
• Front fork cap bolt "1"
From the outer tube.
Before removing the front fork from
the machine, loosen the front fork cap
bolt.
2. Remove:
• Front fork cap bolt "1"
Hold the locknut "2" and remove the
front fork cap bolt.
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 DAMPER ROD
1. Remove:
• Base valve "1"
• Damper rod "2"
Use a damper rod holder "3" to lock
the damper rod.
CHECKING THE DAMPER ROD
1. Inspect:
• Damper rod "1"
Bend/damage→Replace damper
rod.
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:
• Valve assembly "1"
Wear/damage →Replace.
• O-ring "2"
Damage→ Replace.
CHECKING THE FORK SPRING
1. Measure:
• Fork spring free length "a"
Out of specification→Replace.
Damper rod holder:
YM-01494/90890-01494
Fork spring free length:
460 mm (18.1 in)
: 455 mm (17.9
in)

6-19
FRONT FORK
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 FRONT FORK
CAP BOLT
1. Inspect: • Front fork cap bolt "1"
• O-ring "2"
• Air bleed screw "3"Wear/damage →Replace. ASSEMBLING THE FRONT FORK
1. Wash the all parts in a clean sol-
vent.
2. Install:
• Damper rod "1"To inner tube "2".
To install the damper rod into the
inner tube, hold the inner tube
aslant. If the inner tube is held ver-
tically, the damper rod may fall into
it, damaging the valve inside.
3. Install:• Copper washer "1"
• O-ring "2"
• Base valve "3"To inner tube "4".
4. Tighten: • Base valve "1"
• Use a damper rod holder "2" to lock the damper rod "3".
• Apply the LOCTITE
® on the base
valve thread.
5. Install:
• Spring guide "1"
• Locknut "2"To damper rod "3".
• Install the spring guide with its
smaller dia.end "a" facing down-
ward.
• With its thread "b" facing upward,
fully finger tighten the locknut onto
the damper rod.
6. 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.
• Install the oil seal washer with its projections "b" facing upward.
Inner tube bending limit:
0.2 mm (0.008 in)
Base valve:55 Nm (5.5 m•kg, 40
ft•lb)
Damper rod holder: YM-01494/90890-01494

6-20
FRONT FORK
7. Install:
• Piston metal "1"
Install the piston metal onto the slot
on inner tube.
8. Install:
• Outer tube "1"
To inner tube "2".
9. Install:
• Slide metal "1"
• Oil seal washer "2"
To outer tube slot.
Press the slide metal into the outer
tube with fork seal driver "3".
10. Install:
• Oil seal "1"
Press the oil seal into the outer tube
with fork seal driver "2".
11. Install:
• Stopper ring "1"
Fit the stopper ring correctly in the
groove in the outer tube.
12. Install:
• Dust seal "1"
Apply the lithium soap base grease
on the inner tube.
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
recommended fork oil "1".
• 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.
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 distrib-
ute the fork oil once more.
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, re-
peat the steps 15 to 18.
Fork seal driver:
YM-A0948/90890-01502
Fork seal driver:
YM-A0948/90890-01502
Recommended oil:
Suspension oil "S1"

6-21
FRONT FORK
19. Wait ten minutes until the air bub-
bles have been removed from the
front fork, and the oil has dis-
pense evenly in system before
setting recommended oil level.
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 ob-
tain 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.
Be sure to install the spring guide "2"
when checking the oil level.
Never fail to make the oil level ad-
justment between the maximum
and minimum level and always ad-
just each front fork to the same
setting. Uneven adjustment can
cause poor handling and loss of
stability.
21. Measure:
• Distance "a"
Out of specification→Turn into
the locknut.
22. Loosen:
• Rebound damping adjuster "1"
• Loosen the rebound damping ad-
juster finger tight.
• Record the set position of the ad-
juster (the amount of turning out the
fully turned in position).
23. Install:
• Push rod "1"
• Fork spring "2"
• Install the fork spring with the
damper rod "3" pulled up.
• After installing the fork spring, hold
the damper rod end so that it will not
go down.
24. Install:
• Spring seat "1"
• Front fork cap bolt "2"
Fully finger tighten the front fork cap
bolt onto the damper rod.
25. Tighten:
• Front fork cap bolt (locknut) "1"
Hold the locknut "2" and tighten the
front fork cap bolt with specified
torque.
26. Install:
• Front fork cap bolt "1"
To outer tube.
Temporarily tighten the cap bolt.
27. Install:
• Protector guide "1"
Install the protector guide with its wid-
er side "a" facing downward.
Standard oil level:
132 mm (5.20 in)
Extent of adjustment:
95–150 mm (3.74–5.91
in)
From top of outer tube
with inner tube and
damper rod "1" fully
compressed without
spring.
Distance "a":
18 mm (0.71 in) or more
Between damper rod
"1" top and locknut "2"
top.
Front fork cap bolt (lock-
nut):
29 Nm (2.9 m•kg, 21
ft•lb)