2016 YAMAHA WR 250F wheel

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
4-1
EAS2GB7136
CHASSIS
EAS2GB7137SELECTION OF THE SECONDARY REDUC-
TION RATIO (SPROCKET)
reduction ratio>
• It is generally said that the secondary gear ra-
tio should be reduced for a longer straight por-
tion of a speed course and should be
increased for a course with many corners. Ac-
tually, however, as the speed depends on the
ground condition of the day of the race, be
sure to run through the circuit to set the ma-
chine suitable for the entire course.
• In actuality, it is very difficult to achieve set-
tings suitable for the entire course and some
settings may be sacrificed. Thus, the settings
should be matched to the portion of the
course that has the greatest effect on the race
result. In such a case, run through the entire
course while making notes of lap times to find
the best balance; then, determine the second-
ary reduction ratio.
• If a course has a long straight portion where a
machine can run at maximum speed, the ma-
chine is generally set such that it can develop
its maximum revolutions toward the end of the
straight line, with care taken to avoid the en-
gine over-revving.
TIP
Riding technique varies from rider to rider and
the performance of a machine also vary from
machine to machine. Therefore, do not imitate
other rider’s settings from the beginning but
choose your own setting according to the level
of your riding technique.
EAS2GB7138DRIVE AND REAR WHEEL SPROCKETS
SETTING PARTS
EAS2GB7139TIRE PRESSURE
Tire pressure should be adjusted to suit the
road surface condition of the circuit.
• Under a rainy, a muddy, a sandy, or a slippery
condition, the tire pressure should be lower
for a larger area of contact with the road sur-
face. Secondary reduction ratio = Number of
rear wheel sprocket teeth/Number of
drive sprocket teeth
Secondary reduction ratio
3.846 (50/13)
Part name Type Part number
Drive sprocket “1”
(STD) 13T 9383B-13218
Rear wheel sprock-
et “2”
48T 5GS-25448-50
(STD) 50T 5TJ-25450-80
52T 5TJ-25452-80
Standard tire pressure
100 kPa (1.00 kgf/cm
2,15 psi)
Extent of adjustment
60–80 kPa (0.60–0.80 kgf/cm
2, 9–
12 psi)

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.
EAS2GB7143FRONT FORK SETTING PARTS
• Front fork spring “1”
TIP
The I.D. mark (slits) “a” is proved on the end of
the spring.
EAS2GB7144REAR 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.
EAS2GB7145CHOOSING 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)

5
CHASSIS
GENERAL CHASSIS........................................................................................ 5-1
REMOVING THE LEFT SIDE COVER ....................................................... 5-3
REMOVING THE SEAT ............................................................................. 5-3
FRONT WHEEL................................................................................................ 5-4
REMOVING THE FRONT WHEEL............................................................. 5-5
CHECKING THE FRONT WHEEL ............................................................. 5-5
DISASSEMBLING THE FRONT WHEEL ................................................... 5-6
ASSEMBLING THE FRONT WHEEL ......................................................... 5-6
INSTALLING THE FRONT WHEEL ........................................................... 5-7
REAR WHEEL.................................................................................................. 5-9
REMOVING THE REAR WHEEL ............................................................. 5-10
CHECKING THE REAR WHEEL.............................................................. 5-10
DISASSEMBLING THE REAR WHEEL ................................................... 5-10
CHECKING AND REPLACING THE REAR WHEEL SPROCKET .......... 5-10
ASSEMBLING THE REAR WHEEL ......................................................... 5-11
INSTALLING THE REAR WHEEL............................................................ 5-11
FRONT BRAKE.............................................................................................. 5-13
INTRODUCTION ...................................................................................... 5-17
CHECKING THE FRONT BRAKE DISC .................................................. 5-17
REMOVING THE FRONT BRAKE CALIPER ........................................... 5-17
DISASSEMBLING THE FRONT BRAKE CALIPER................................. 5-17
CHECKING THE FRONT BRAKE CALIPER ........................................... 5-18
ASSEMBLING THE FRONT BRAKE CALIPER ....................................... 5-18
INSTALLING THE BRAKE CALIPER PISTON ........................................ 5-18
INSTALLING THE FRONT BRAKE CALIPER ......................................... 5-19
REMOVING THE FRONT BRAKE MASTER CYLINDER ........................ 5-20
CHECKING THE FRONT BRAKE MASTER CYLINDER......................... 5-20
ASSEMBLING THE FRONT BRAKE MASTER CYLINDER .................... 5-20
INSTALLING THE FRONT BRAKE MASTER CYLINDER....................... 5-21
REAR BRAKE................................................................................................ 5-23
INTRODUCTION ...................................................................................... 5-27
CHECKING THE REAR BRAKE DISC..................................................... 5-27
REMOVING THE REAR BRAKE CALIPER ............................................. 5-28
DISASSEMBLING THE REAR BRAKE CALIPER ................................... 5-28
CHECKING THE REAR BRAKE CALIPER .............................................. 5-28
ASSEMBLING THE REAR BRAKE CALIPER ......................................... 5-28
INSTALLING THE BRAKE CALIPER PISTON ........................................ 5-29
INSTALLING THE REAR BRAKE CALIPER ............................................ 5-29
REMOVING THE REAR BRAKE MASTER CYLINDER .......................... 5-30
CHECKING THE REAR BRAKE MASTER CYLINDER ........................... 5-30
ASSEMBLING THE REAR BRAKE MASTER CYLINDER....................... 5-30
INSTALLING THE REAR BRAKE MASTER CYLINDER ......................... 5-31

HANDLEBAR................................................................................................. 5-33
REMOVING THE HANDLEBAR............................................................... 5-35
CHECKING THE HANDLEBAR ............................................................... 5-35
INSTALLING THE HANDLEBAR ............................................................. 5-35
FRONT FORK................................................................................................. 5-40
REMOVING THE FRONT FORK LEGS ................................................... 5-42
DISASSEMBLING THE FRONT FORK LEGS ......................................... 5-42
CHECKING THE FRONT FORK LEGS ................................................... 5-43
ASSEMBLING THE FRONT FORK LEGS ............................................... 5-44
INSTALLING THE FRONT FORK LEGS ................................................. 5-50
STEERING HEAD........................................................................................... 5-53
REMOVING THE LOWER BRACKET...................................................... 5-55
CHECKING THE STEERING HEAD ........................................................ 5-55
INSTALLING THE STEERING HEAD ...................................................... 5-55
REAR SHOCK ABSORBER ASSEMBLY..................................................... 5-58
HANDLING THE REAR SHOCK ABSORBER ......................................... 5-61
DISPOSING OF A REAR SHOCK ABSORBER ...................................... 5-61
REMOVING THE REAR SHOCK ABSORBER ASSEMBLY.................... 5-61
REMOVING THE BEARING..................................................................... 5-61
CHECKING THE REAR SHOCK ABSORBER ASSEMBLY .................... 5-62
CHECKING THE CONNECTING ARM AND RELAY ARM ...................... 5-62
INSTALLING THE RELAY ARM............................................................... 5-62
INSTALLING THE REAR SHOCK ABSORBER ASSEMBLY .................. 5-63
SWINGARM.................................................................................................... 5-65
REMOVING THE SWINGARM................................................................. 5-66
REMOVING THE BEARING..................................................................... 5-66
CHECKING THE SWINGARM ................................................................. 5-66
INSTALLING THE SWINGARM ............................................................... 5-67
CHAIN DRIVE................................................................................................. 5-68
REMOVING THE DRIVE CHAIN.............................................................. 5-69
CHECKING THE DRIVE CHAIN .............................................................. 5-69
CHECKING THE DRIVE SPROCKET...................................................... 5-70
CHECKING THE REAR WHEEL SPROCKET ......................................... 5-70
INSTALLING THE DRIVE CHAIN ............................................................ 5-70

FRONT WHEEL
5-4
EAS2GB7154
FRONT WHEEL
Removing the front wheel
Order Part name Q’ty Remarks
Use a suitable stand to raise the front wheel
off the ground.
1 Front wheel axle pinch bolt 4 Loosen.
2 Front wheel axle nut 1
3 Front wheel axle 1
4 Front wheel 1
5 Speed sensor 1
6Collar 1
7 Oil seal 1
8 Bearing 2
9 Brake disc 1
For installation, reverse the removal proce-
dure.
12 Nm (1.2 m kgf, 8.7 ft Ibf)T.R.
New
LT
LS
LS
LS
8
7 8
(6)
9
12
1 3
21 Nm (2.1 m kgf, 15 ft Ibf)T.R.
21 Nm (2.1 m kgf, 15 ft Ibf)T.R.
4
90 Nm (9.0 m kgf, 65 ft lbf)T.R.
5
6

FRONT WHEEL
5-5
EAS2GB7155REMOVING THE FRONT WHEEL
1. Use a suitable stand to raise the front wheel
off the ground.
EWA
WARNING
Securely support the vehicle so that there is
no danger of it falling over.
2. Remove:
• Front wheel
EAS2GB7156CHECKING THE FRONT WHEEL
1. Check:
• Front wheel axle
Roll the front wheel axle on a flat surface.
Bends  Replace.
EWA
WARNING
Do not attempt to straighten a bent wheel
axle.
2. Check:
•Tire(s)
• Front wheel
Damage/wear  Replace.
Refer to “CHECKING THE TIRES” on page
3-35 and “CHECKING THE WHEELS” on
page 3-36.
3. Check:
• Spokes
Bend/damage  Replace.
Loose  Tighten.
Tap the spokes with a screwdriver.
TIP
A tight spoke will emit a clear, ringing tone; a
loose spoke will sound flat.
4. Tighten:
• Spokes
Refer to “CHECKING AND TIGHTENING
THE SPOKES” on page 3-35.
TIP
After tightening the spokes, measure the wheel
runout.
5. Measure:
• Wheel radial runout “a”
• Wheel lateral runout “b”
Out of specification  Repair/replace.
6. Check:
•Collars
Damage/wear  Replace.
7. Check:
• Bearing
Front wheel turns roughly or is loose  Re-
place the wheel bearings.
• Oil seals
Damage/wear  Replace.
Spokes
2.5 Nm (0.25 m·kgf, 1.8 ft·lbf)
Radial wheel runout limit
2.0 mm (0.08 in)
Lateral wheel runout limit
2.0 mm (0.08 in)
T R..
ab

FRONT WHEEL
5-6
EAS2GB7157DISASSEMBLING THE FRONT WHEEL
1. Remove:
• Oil seals
• Bearings
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Clean the outside of the front wheel hub.
b. Remove the oil seals “1” with a flat-head
screwdriver.
TIP
To prevent damaging the wheel, place a rag “2”
between the screwdriver and the wheel sur-
face.
c. Remove the bearings with a bearing puller.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
EAS2GB7158ASSEMBLING THE FRONT WHEEL
1. Install:
• Bearing (left side) “1”
• Spacer “2”
• Bearing (right side) “3”
• Oil seal “4”
TIP
• Apply the lithium-soap-based grease to the
bearing and the oil seal lip when installing.
• Left side of bearing shall be installed first.
• Install the oil seal with its manufacture’s
marks or numbers facing outward.
ECA
NOTICE
Install the bearing by pressing its outer race
parallel.
TIP
Use a socket “1” that matches the diameter of
the bearing outer race and that of the oil seal.
2. Install:
• Brake disc “1”
• Brake disc bolt “2”
TIP
Tighten the bolts in stages and in a crisscross
pattern.
12
New
Brake disc bolt
12 Nm (1.2 m·kgf, 8.7 ft·lbf)
LOCTITE®
3
2
1
4
New
1
T R..