length YAMAHA WR 250F 2015 User Guide

CHASSIS
3-24
EAS2GB2103
CHASSIS
EAS2GB2104BLEEDING THE BRAKE SYSTEMEWA
WARNING
Bleed the brake system whenever:
• The system is disassembled.
• A brake hose is loosened, disconnected,
or replaced.
• The brake fluid level is very low.
• Brake operation is faulty.
1. Remove:
• Brake master cylinder cap
• Reservoir diaphragm
• Reservoir float (front brake)
• Protector (rear brake)
TIP
• Be careful not to spill any brake fluid or allow
the reservoir to overflow.
• Make sure that there is enough brake fluid be-
fore applying the brake. Ignoring this precau-
tion could allow air to enter the brake system,
considerably lengthening the bleeding proce-
dure.
• If bleeding is difficult, it may be necessary to
let the brake fluid settle for a few hours. Re-
peat the bleeding procedure when the tiny
bubbles in the hose have disappeared.
2. Bleed the brake system.
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a. Fill the reservoir to the proper level with the
recommended brake fluid.
b. Install the reservoir diaphragm.
c. Connect the plastic hose “1” to the bleed
screw “2” securely, and place a container
under the end of the plastic hose.d. Slowly apply the brake several times.
e. Fully pull the brake lever or fully press down
the brake pedal and hold it in position.
f. Loosen the bleed screw.
TIP
Loosening the bleed screw will release the
pressure in the brake caliper and cause the
brake lever to contact the throttle grip or the
brake pedal to fully extend.
g. Tighten the bleed screw and then release
the brake lever or brake pedal.
h. Repeat steps (d) to (g) until all of the air bub-
bles have disappeared from the brake fluid
in the plastic hose.
TIP
During the procedure, keep adding brake fluid
to the reservoir.
ECA
NOTICE
• Wipe off any brake fluid on the brake
discs, tires, wheels, etc.
• Brake fluid may erode painted surfaces or
plastic parts. Always clean up spilled fluid
immediately.
i. Tighten the bleed screw.
j. Pour brake fluid to the reservoir up to the
specified level.
Refer to “CHECKING THE BRAKE FLUID
LEVEL” on page 3-29.
EWA
WARNING
After bleeding the hydraulic brake system,
check the brake operation.
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1 2
A
A. Front
B. Rear
Bleed screw
6 Nm (0.6 m·kgf, 4.3 ft·lbf)
2
1B
T R..

CHASSIS
3-33
EAS2GB2118CHECKING THE SWINGARM OPERATION
1. Check:
• Swingarm smooth action
• Swingarm free play
Refer to “SWINGARM” on page 5-64.
EAS2GB2119CHECKING THE REAR SUSPENSION
1. Stand the vehicle upright on a level surface.
EWA
WARNING
Securely support the vehicle so that there is
no danger of it falling over.
2. Check:
• Rear shock absorber assembly
Gas leaks/oil leaks  Replace the rear
shock absorber assembly.
Refer to “REAR SHOCK ABSORBER AS-
SEMBLY” on page 5-57.
3. Check:
• Rear shock absorber assembly smooth ac-
tion
• Rear suspension link smooth action
Sit astride the seat and shake your body up
and down several times to check whether
the rear shock absorber assembly operates
smoothly.
Unsmooth operation  Correct or replace.
Refer to “REAR SHOCK ABSORBER AS-
SEMBLY” on page 5-57.
EAS2GB2120ADJUSTING THE REAR SHOCK ABSORB-
ER ASSEMBLY
Use a suitable stand to raise the rear wheel off
the ground.
EWA
WARNING
Securely support the vehicle so that there is
no danger of it falling over.Spring preload
ECA
NOTICE
Do not turn the adjuster forcibly beyond its
adjusting range.
1. Remove:
• Rear frame
Refer to “REAR SHOCK ABSORBER AS-
SEMBLY” on page 5-57.
2. Adjust:
• Spring preload
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a. Loosen the locknut “1”.
b. Loosen the adjuster “2” until there is some
clearance between the spring and the ad-
juster.
c. Measure the spring free length “a”.
d. Turn the adjuster in the direction of “b” or “c”
to make an adjustment.
Direction “b”
Spring preload is increased (suspen-
sion is harder).
Direction “c”
Spring preload is decreased (suspen-
sion is softer).
Spring installed length “d”
Minimum
Position in which the spring is
turned in 1.5 mm (0.06 in) from
its free length.
STD
Position in which the spring is
turned in 10 mm (0.39 in) from its
free length.
Maximum
Position in which the spring is
turned in 18 mm (0.71 in) from its
free length.

CHASSIS
3-34
TIP
• Be sure to remove all dirt and mud from
around the locknut and adjusting ring before
adjustment.
• The length of the spring (installed) changes
1.5 mm (0.06 in) per turn of the adjusting ring.
e. Tighten the locknut.
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3. Install:
• Rear frame
Refer to “REAR SHOCK ABSORBER AS-
SEMBLY” on page 5-57.
Rebound damping force
ECA
NOTICE
Do not turn the adjuster forcibly beyond its
adjusting range.
1. Adjust:
• Rebound damping force
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Turn the adjuster “1” in the direction of “a” or
“b” to make an adjustment.
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High compression dampingECA
NOTICE
Do not turn the adjuster forcibly beyond its
adjusting range.
1. Adjust:
• High compression damping
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Turn the adjuster “1” in the direction of “a” or
“b” to make an adjustment. Locknut
30 Nm (3.0 m·kgf, 22 ft·lbf)
Direction “a”
Rebound damping force is increased
(suspension is harder).
Direction “b”
Rebound damping force is decreased
(suspension is softer).
c
b
d
T R..
Rebound damping force
Maximum
Turn it in finger-tight.
STD
Turn it out by 14 clicks.*
Minimum
Turn it out by 30 clicks.*
* With the adjuster fully turned
Direction “a”
High compression damping force is in-
creased (suspension is harder).
Direction “b”
High compression damping force is de-
creased (suspension is softer).
High compression damping
Maximum
Turn it in finger-tight.
STD
Turn it out by 1 1/4 turns.*
Minimum
Turn it out by two turns.*
* With the adjuster fully turned
a
b
1

4
TUNING
CHASSIS.......................................................................................................... 4-1
SELECTION OF THE SECONDARY REDUCTION RATIO
(SPROCKET) ............................................................................................ 4-1
DRIVE AND REAR WHEEL SPROCKETS SETTING PARTS .................. 4-1
TIRE PRESSURE....................................................................................... 4-1
FRONT FORK SETTING............................................................................ 4-2
CHANGE IN AMOUNT AND CHARACTERISTICS OF FORK OIL............ 4-2
SETTING OF SPRING AFTER REPLACEMENT ...................................... 4-2
FRONT FORK SETTING PARTS............................................................... 4-3
REAR SUSPENSION SETTING ................................................................ 4-3
CHOOSING SET LENGTH ........................................................................ 4-3
SETTING OF SPRING AFTER REPLACEMENT ...................................... 4-4
REAR SHOCK ABSORBER SETTING PARTS ......................................... 4-4
SUSPENSION SETTING (FRONT FORK)................................................. 4-6
SUSPENSION SETTING (REAR SHOCK ABSORBER) ........................... 4-7

CHASSIS
4-3
TIP
Generally a stiff spring gives a stiff riding feel-
ing. Rebound damping tends to become weak-
er, resulting in lack of a sense of contact with
the road surface or in a vibrating handlebar.
EAS2GB2145FRONT FORK SETTING PARTS
• Front fork spring “1”
TIP
The I.D. mark (slits) “a” is proved on the end of
the spring.
EAS2GB2146
REAR SUSPENSION SETTING
The rear shock absorber setting should be
made depending on the rider’s feeling of an ac-
tual run and the circuit conditions.
The rear suspension setting includes the fol-
lowing two factors:
1. Setting of spring preload
• Change the set length of the spring.
• Change the spring.
2. Setting of damping force
• Change the rebound damping force.
• Change the compression damping force.
EAS2GB2147CHOOSING SET LENGTH
1. Place a stand or a block under the engine to
put the rear wheel above the floor, and mea-
sure the length “a” between the rear wheel
axle center and the rear fender holding bolt.
2. Remove the stand or block from the engine
and, with a rider astride the seat, measure
the sunken length “b” between the rear
wheel axle center and the rear fender hold-
ing bolt.
3. Loosen the locknut “1” and make adjustment
by turning the adjuster “2” to achieve the
standard figure from the subtraction of the
length “b” from the length “a”. TypeSpring
rate N/
mmPart numberI.D.
Mark
(slits)
SOFT4.1 2GB-23141-A0 |||
4.2 2GB-23141-B0 ||||
4.3 2GB-23141-C0 |||||
STD 4.42GB-23141-30 —
2GB-23141-D0 |-|
STIFF4.5 2GB-23141-E0 |-||
4.6 33D-23141-30 |-|||
a
1
Standard figure
90–100 mm (3.5–3.9 in)

CHASSIS
4-4
TIP
• If the machine is new and after it is broken in,
the same set length of the spring may change
because of the initial fatigue, etc. of the
spring. Therefore, be sure to make reevalua-
tion.
• If the standard figure cannot be achieved by
adjusting the adjuster and changing the set
length, replace the spring with an optional one
and make readjustment.
EAS2GB2148SETTING OF SPRING AFTER REPLACE-
MENT
After replacement, be sure to adjust the spring
to the set length [sunken length 90–100 mm
(3.5–3.9 in)] and set it.
1. Use of soft spring
• Adjust to decrease rebound damping force
to compensate for less spring load. Run with
the rebound damping force adjuster one or
two clicks turned out, and readjust it to suit
your preference.
2. Use of stiff spring
• Adjust to increase rebound damping force to
compensate for greater spring load. Run
with the rebound damping force adjuster
one or two clicks turned in, and readjust it to
suit your preference.
TIP
Adjusting the rebound damping force will be fol-
lowed more or less by a change in the com-
pression damping force. For correction, adjust
to decrease compression damping force.
EWA
WARNING
When using a rear shock absorber other
than currently installed, use the one whose
overall length “a” does not exceed the stan-
dard as it may result in faulty performance.
Never use one whose overall length is
greater than standard.
EAS2GB2149REAR SHOCK ABSORBER SETTING
PARTS
• Rear shock spring “1”
TIP
• The I.D. mark “a” is marked at the end of the
spring.
• Spring specification varies according to the
color of I.D. marks.
Length “a” of standard shock
462.5 mm (18.21 in)
TypeSpring
rate N/
mmPart numberI.D.
Mark
SOFT482GB-22212-10
(Blue)Black
502GB-22212-00
(Blue)Green
521SL-22212-40
(Blue)Yellow
STD 541SL-22212-60
(Blue)Pink
STIFF561SL-22212-20
(Blue)White
581SL-22212-00
(Blue)Silver
601SL-22212-80
(Blue)Brown

CHASSIS
4-5
• Extent of adjustment (spring preload)
TIP
For the spring preload adjustment, refer to “AD-
JUSTING THE REAR SHOCK ABSORBER
ASSEMBLY” on page 3-33.Maximum Minimum
Position in which
the spring is turned
in 18 mm (0.71 in)
from its free length.Position in which
the spring is turned
in 1.5 mm (0.06 in)
from its free length.

CHASSIS
4-6
EAS2GB2150SUSPENSION SETTING (FRONT FORK)
TIP
• If any of the following symptoms is experienced with the standard position as the base, make reset-
ting by reference to the adjustment procedure given in the same chart.
• Before any change, set the rear shock absorber sunken length to the standard figure 90–100 mm
(3.5–3.9 in).
SymptomSection
Check Adjust
JumpLarge
gapMedi-
um
gapSmall
gap
Stiff over entire
rangeCompression
damping forceTurn adjuster counterclock-
wise (about 2 clicks) to de-
crease damping.
Oil amount Decrease oil amount by about
5–10 cm
3 (0.2–0.3 US oz, 0.2–
0.4 Imp.oz).
Spring Replace with soft spring.
Unsmooth
movement over
entire rangeOuter tube
Inner tubeCheck for any bends, dents,
other noticeable scars, etc. If
any, replace affected parts.
Slide metal Replace with a new one for ex-
tended use.
Piston metal Replace with a new one for ex-
tended use.
Lower bracket
tightening
torqueRetighten to specified torque.
Poor initial
movementRebound
damping forceTurn adjuster counterclock-
wise (about 2 clicks) to de-
crease damping.
Oil seals Apply grease in oil seal wall.
Soft over entire
range, bottom-
ing outCompression
damping forceTurn adjuster clockwise (about
2 clicks) to increase damping.
Oil amount Increase oil amount by about
5–10 cm
3 (0.2–0.3 US oz, 0.2–
0.4 Imp.oz).
Spring Replace with stiff spring.
Stiff toward
stroke endOil amountDecrease oil amount by about
5 cm
3 (0.2 US oz, 0.2 Imp.oz).
Soft toward
stroke end, bot-
toming outOil amountIncrease oil amount by about 5
cm
3 (0.2 US oz, 0.2 Imp.oz).
Stiff initial
movementCompression
damping forceTurn adjuster counterclock-
wise (about 2 clicks) to de-
crease damping.

CHASSIS
4-7
EAS2GB2151SUSPENSION SETTING (REAR SHOCK ABSORBER)
TIP
• If any of the following symptoms is experienced with the standard position as the base, make reset-
ting by reference to the adjustment procedure given in the same chart.
• Adjust the rebound damping in 2-click increments or decrements.
• Adjust the low compression damping in 1-click increments or decrements.
• Adjust the high compression damping in 1/6 turn increments or decrements. Low front, tend-
ing to lower
front postureCompression
damping forceTurn adjuster clockwise (about
2 clicks) to increase damping.
Rebound
damping forceTurn adjuster counterclock-
wise (about 2 clicks) to de-
crease damping.
Balance with
rear endSet sunken length for 95–100
mm (3.7–3.9 in) when one
passenger is astride seat (low-
er rear posture).
Oil amount Increase oil amount by about 5
cm
3 (0.2 US oz, 0.2 Imp.oz).
“Obtrusive”
front, tending to
upper front pos-
tureCompression
damping forceTurn adjuster counterclock-
wise (about 2 clicks) to de-
crease damping.
Balance with
rear endSet sunken length for 90–95
mm (3.5–3.7 in) when one
passenger is astride seat (up-
per rear posture).
Spring Replace with soft spring.
Oil amount Decrease oil amount by about
5–10 cm
3 (0.2–0.3 US oz, 0.2–
0.4 Imp.oz).
SymptomSection
Check Adjust
JumpLarge
gapMedi-
um
gapSmall
gap
Stiff, tending to
sinkRebound
damping forceTurn adjuster counterclock-
wise (about 2 clicks) to de-
crease damping.
Spring set
lengthSet sunken length for 90–100
mm (3.5–3.9 in) when one
passenger is astride seat.
Spongy and un-
stableRebound
damping forceTurn adjuster clockwise (about
2 clicks) to increase damping.
Low compres-
sion dampingTurn adjuster clockwise (about
1 click) to increase damping.
Spring Replace with stiff spring. SymptomSection
Check Adjust
JumpLarge
gapMedi-
um
gapSmall
gap

CHASSIS
4-8
Heavy and
draggingRebound
damping forceTurn adjuster counterclock-
wise (about 2 clicks) to de-
crease damping.
Spring Replace with soft spring.
Poor road grip-
pingRebound
damping forceTurn adjuster counterclock-
wise (about 2 clicks) to de-
crease damping.
Low compres-
sion dampingTurn adjuster clockwise (about
1 click) to increase damping.
High compres-
sion dampingTurn adjuster clockwise (about
1/6 turn) to increase damping.
Spring set
lengthSet sunken length for 90–100
mm (3.5–3.9 in) when one
passenger is astride seat.
Spring Replace with soft spring.
Bottoming outHigh compres-
sion dampingTurn adjuster clockwise (about
1/6 turn) to increase damping.
Spring set
lengthSet sunken length for 90–100
mm (3.5–3.9 in) when one
passenger is astride seat.
Spring Replace with stiff spring.
BouncingRebound
damping forceTurn adjuster clockwise (about
2 clicks) to increase damping.
Spring Replace with soft spring.
Stiff travelHigh compres-
sion dampingTurn adjuster counterclock-
wise (about 1/6 turn) to de-
crease damping.
Spring set
lengthSet sunken length for 90–100
mm (3.5–3.9 in) when one
passenger is astride seat.
Spring Replace with soft spring. SymptomSection
Check Adjust
JumpLarge
gapMedi-
um
gapSmall
gap