Fork YAMAHA YZ250F 2015 User Guide

MAINTENANCE INTERVALS
3-2
PISTON RING
Inspect Check the end gap of the pis-
ton ring.
Replace Replace the piston, piston pin,
piston pin clip, and piston ring
all as a set.
PISTON PIN
Inspect
Replace Replace the piston, piston pin,
piston pin clip, and piston ring
all as a set.
CYLINDER HEAD Check the coolant passages
for corrosion.
Inspect carbon deposits and
eliminate them.
Inspect and clean Check for warpage, and re-
place the gasket.
CYLINDER
Inspect and clean Inspect score marks.
Replace Inspect wear.
ENGINE OIL
Inspect Check the engine oil amount.
Replace
OIL FILTER ELE-
MENT
Replace
OIL STRAINER
Clean
CLUTCH
Inspect and adjust Inspect housing, friction plate,
clutch plate and spring.
Replace
TRANSMISSION
Inspect
Replace bearings
SHIFT FORK, SHIFT
CAM, GUIDE BAR
Inspect Inspect wear.ITEMAfter
break-
inEvery
race
(about
2.5
hours)Every
third
(about
7.5
hours)Every
fifth
(about
12.5
hours)As re-
quiredRemarks

MAINTENANCE INTERVALS
3-4
FUEL TANK, FUEL
PUMP
Inspect
FUEL HOSE
Inspect
Replace Every four years
FRONT FORK LEG
(S)
Clean Dust seal
Inspect and adjust
Replace oil
Replace oil seal
Clean and grease
oil seals and dust
sealsLithium soap base grease
PROTECTOR
GUIDE
Replace
REAR SHOCK AB-
SORBER
Inspect and adjust
Lubricate(After
rain
ride)Grease pillow balls and bear-
ings.
Retighten Check for tightening torques.
BRAKE(S)
Adjust lever posi-
tion and pedal
height
Lubricate pivot
point
Check brake disc
surface
Check fluid level
and leakage
Retighten brake
disc bolts, caliper
bolts, master cylin-
der bolts and union
boltsCheck for tightening torques.
Replace padsITEMAfter
break-
inEvery
race
(about
2.5
hours)Every
third
(about
7.5
hours)Every
fifth
(about
12.5
hours)As re-
quiredRemarks

PRE-OPERATION INSPECTION AND MAINTENANCE
3-7
EAS1SM5068
PRE-OPERATION INSPECTION AND MAINTENANCE
Before riding for break-in operation, practice or a race, make sure the machine is in good operating
condition.
Before using this machine, check the following points.
EAS1SM5069GENERAL INSPECTION AND MAINTENANCE
TIP
Perform usual maintenance enough so that, in the race course, a confirmation of that and simple set-
ting adjustments may only be left, in order to get enough time to use effectively.ITEM inspect Page
CoolantCheck that coolant is filled up to the radiator cap.
Check the cooling system for leakage.3-8 – 10
FuelCheck that a fresh gasoline is filled in the fuel tank.
Check the fuel line for leakage.1-22
Engine oilCheck that the oil level is correct. Check the crank-
case and oil line for leakage.3-14 – 16
Gear shifter and clutchCheck that gears can be shifted correctly in order and
that the clutch operates smoothly.3-10 – 11
Throttle grip/HousingCheck that the throttle grip operation and free play
are correctly adjusted. Lubricate the throttle grip and
housing, if necessary.3-11 – 12
BrakesCheck the play of front brake and effect of front and
rear brake.3-21 – 27
Drive chainCheck drive chain slack and alignment. Check that
the drive chain is lubricated properly.3-27
4-64 – 65
WheelsCheck for excessive wear and tire pressure. Check
for loose spokes and have no excessive play.3-32 – 33
SteeringCheck that the handlebar can be turned smoothly and
have no excessive play.3-33 – 34
Front forks and rear
shock absorberCheck that they operate smoothly and there is no oil
leakage.3-28 – 32
Cables (wires)Check that the clutch and throttle cables move
smoothly. Check that they are not caught when the
handlebars are turned or when the front forks travel
up and down.—
Exhaust pipeCheck that the exhaust pipe is tightly mounted and
has no cracks.3-13 – 14
Rear wheel sprocketCheck that the rear wheel sprocket tightening bolt is
not loose.4-8 – 9
Lubrication Check for smooth operation. Lubricate if necessary. 3-12, 3-34
Bolts and nutsCheck the chassis and engine for loose bolts and
nuts.1-25 – 26
Lead connectorsCheck that the AC magneto, ECU and ignition coil are
connected tightly.1-12 – 14
SettingsIs the machine set suitably for the condition of the rac-
ing course and weather or by taking into account the
results of test runs before racing? Are inspection and
maintenance completely done?10-1 – 8

CHASSIS
3-24
b. Loosen the pad pin “2”.
c. Remove the brake caliper “3” from the front
fork.
d. Remove the pad pin and brake pads “4”.
e. Connect the plastic hose “5” to the bleed
screw “6” and place a container under the
end of the plastic hose.
f. Loosen the bleed screw and push the brake
caliper piston in.
EWA@
WARNING
Do not reuse the drained brake fluid.
g. Tighten the bleed screw.
h. Install the brake pads “7” and the pad pin.
TIP
• Install the brake pads with their projections “a”
into the brake caliper recesses “b”.
• Temporarily tighten the pad pin at this point.i. Install the brake caliper “8” and tighten the
pad pin “9”.
j. Install the pad pin plug “10”.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
3. Check:
• Brake fluid level
Refer to “CHECKING THE BRAKE FLUID
LEVEL” on page 3-26.
4. Check:
• Brake lever operation
A softy or spongy feeling  Bleed the brake
system.
Refer to “BLEEDING THE BRAKE SYS-
TEM” on page 3-21. Bleed screw
6 Nm (0.6 m·kgf, 4.3 ft·lbf)
3
2
4
6
5
T R..
Bolt (brake caliper)
28 Nm (2.8 m·kgf, 20 ft·lbf)
Pad pin
17 Nm (1.7 m·kgf, 12 ft·lbf)
Pad pin plug
2.5 Nm (0.25 m·kgf, 1.8 ft·lbf)
7
a b
T R..
8
9
T R..
10

CHASSIS
3-28
EAS1SM5100CHECKING THE FRONT FORK LEGS
1. Stand the vehicle upright on a level surface.
EWA13120
WARNING
Securely support the vehicle so that there is
no danger of it falling over.
2. Check:
• Inner tube
Damage/scratches  Replace.
• Front fork leg (s)
Oil leaks between inner tube and outer tube
 Replace the oil seal.
3. Hold the vehicle upright and apply the front
brake.
4. Check:
• Front fork operation
Push down hard on the handlebar several
times and check if the front fork rebounds
smoothly.
Unsmooth operation  Correct or replace.
Refer to “FRONT FORK” on page 4-37.
EAS1SM5101CHECKING THE FRONT FORK PROTEC-
TOR GUIDE
1. Check:
• Protector guide “1”
Out of specification  Replace.
TIP
The protector guide reaches the limit of its use
when it is worn down to the same height “a” as
of the outer tube circumference.
EAS1SM5102
CLEANING THE FRONT FORK OIL SEAL
AND DUST SEAL
1. Remove:
•Protector
• Dust seal “1”
ECA?
NOTICE
Be careful not to damage the dust seal and
the inner tube by a driver.
2. Clean:
• Dust seal “a”
• Oil seal “b”
TIP
• Clean the dust seal and oil seal after every
run.
• Apply lithium-soap-based grease on the inner
tube.
EAS1SM5103AIR BLEEDING FROM FRONT FORK
TIP
If the front fork initial movement feels stiff dur-
ing a run, relieve the front fork internal pres-
sure.
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 the air bleed screw “1” and release
the internal pressure from the front fork.
1
a
1
LS
a
b

CHASSIS
3-29
3. Tighten:
• Air bleed screw
EAS1SM5104ADJUSTING THE FRONT FORK LEGSEWA32D1006
WARNING
• Always adjust the left and right front forks
evenly. If this is not done, the vehicle may
have poor stability.
• Securely support the vehicle so that there
is no danger of it falling over.
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.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
Compression damping forceECA@
NOTICE
Do not turn the adjuster forcibly beyond its
adjusting range.
1. Adjust:
• Compression damping force
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Turn the adjuster “1” in the direction of “a” or
“b” to make an adjustment.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
Air bleed screw
1.3 Nm (0.13 m·kgf, 0.94 ft·lbf)
Direction “a”
Rebound damping force is increased
(suspension is harder).
Direction “b”
Rebound damping force is decreased
(suspension is softer).
Rebound damping force
Maximum
Turn it in finger-tight.
STD
Turn it out by 12 clicks.*
(USA) (CAN)
Turn it out by 8 clicks.*
(EUR) (JPN) (AUS) (NZL) (ZAF)
Minimum
Turn it out by 20 clicks.*
* With the adjuster fully turned in
T R..
1
Direction “a”
Compression damping force is in-
creased (suspension is harder).
Direction “b”
Compression damping force is de-
creased (suspension is softer).
Compression damping force
Maximum
Turn it in finger-tight.
STD
Turn it out by 10 clicks.*
(USA) (CAN)
Turn it out by 6 clicks.*
(EUR) (JPN) (AUS) (NZL) (ZAF)
Minimum
Turn it out by 20 clicks.*
* With the adjuster fully turned in
1
a
b
a b
1

CHASSIS
3-33
2. Tighten:
• Spokes
Use a spoke nipple wrench “1” for tighten-
ing.
TIP
• Do not give a half turn (180 °) or more for one
tightening.
• Make sure that tightening after a break-in is
done until the initial looseness in nipples dis-
appears.
• Make sure that tightening is done in stages,
not at a time.
EAS1SM5110CHECKING THE WHEELS
1. Check:
• Wheel (s)
Damage/out-of-round  Replace.
EWA13260
WARNING
Never attempt to make any repairs to the
wheel.
TIP
After replacing a tire or a wheel, always bal-
ance the wheel.
EAS1SM5111CHECKING THE WHEEL BEARINGS
1. Check:
• Wheel bearings
“CHECKING THE FRONT WHEEL” on page
4-4and “CHECKING THE REAR WHEEL”
on page 4-8.
EAS1SM5112
CHECKING AND ADJUSTING THE STEER-
ING HEAD
1. Use a suitable stand to raise the front wheel
off the ground.
EWA13120
WARNING
Securely support the vehicle so that there is
no danger of it falling over.
2. Check:
• Steering head
Grasp the bottom of the front fork legs and
gently rock the front fork.
Blinding/looseness  Adjust the steering
head.
3. Remove:
• Handlebar
Refer to “HANDLEBAR” on page 4-31.
• Upper bracket
Refer to “STEERING HEAD” on page 4-49.
4. Adjust:
• Steering head
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Remove the washer “1”.
b. After loosening the ring nut “2” with a steer-
ing nut wrench “3”, tighten it to the specified
torque.
TIP
• Set the torque wrench at a right angle to the
steering nut wrench.
• Move the steering to the left and right a couple
of times to check that it moves smoothly. Spoke nipple wrench (6–7)
90890-01521
YM-01521
Spokes
2.5 Nm (0.25 m·kgf, 1.8 ft·lbf)
1
T R..
1
3
2

CHASSIS
3-34
c. Turn the front fork to the right and left a few
times, and make sure that the steering ro-
tates smoothly. If it does not turn smoothly,
remove the lower bracket and check the up-
per and lower bearings.
Refer to “STEERING HEAD” on page 4-49.
d. Loosen the ring nut fully turn and then tight-
en it to specification with a steering nut
wrench.
EWA13140
WARNING
Do not overtighten the lower ring nut.
e. Check the steering head for looseness or
binding by turning the front fork all the way in
both directions. If any binding is felt, remove
the lower bracket and check the upper and
lower bearings.
Refer to “STEERING HEAD” on page 4-49.
f. Install the washer “1”.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
5. Install:
• Upper bracket
Refer to “STEERING HEAD” on page 4-49.
• Handlebar
Refer to “HANDLEBAR” on page 4-31.
EAS1SM5113
LUBRICATING THE LEVERS
1. Lubricate the pivoting points and metal-to-
metal moving parts of the following parts.
•Brake lever
• Clutch lever
EAS1SM5114LUBRICATING THE PEDAL
1. Lubricate the pivoting point and metal-to-
metal moving parts of the pedal. Steering nut wrench
90890-01403
Exhaust flange nut wrench
YU-A9472
Ring nut (initial tightening torque)
38 Nm (3.8 m·kgf, 27 ft·lbf)
Ring nut (final tightening torque)
7 Nm (0.7 m·kgf, 5.1 ft·lbf)
T R..
T R..
1
Recommended lubricant
Silicone grease
Recommended lubricant
Lithium-soap-based grease
Recommended lubricant
Lithium-soap-based grease

HANDLEBAR................................................................................................. 4-31
REMOVING THE HANDLEBAR............................................................... 4-33
CHECKING THE HANDLEBAR ............................................................... 4-33
INSTALLING THE HANDLEBAR ............................................................. 4-33
FRONT FORK................................................................................................. 4-37
REMOVING THE FRONT FORK LEGS ................................................... 4-39
DISASSEMBLING THE FRONT FORK LEGS ......................................... 4-39
CHECKING THE FRONT FORK LEGS ................................................... 4-40
ASSEMBLING THE FRONT FORK LEGS ............................................... 4-41
INSTALLING THE FRONT FORK LEGS ................................................. 4-47
STEERING HEAD........................................................................................... 4-49
REMOVING THE LOWER BRACKET...................................................... 4-50
CHECKING THE STEERING HEAD ........................................................ 4-50
INSTALLING THE STEERING HEAD ...................................................... 4-50
REAR SHOCK ABSORBER ASSEMBLY..................................................... 4-53
HANDLING THE REAR SHOCK ABSORBER ......................................... 4-56
DISPOSING OF A REAR SHOCK ABSORBER ...................................... 4-56
REMOVING THE REAR SHOCK ABSORBER ASSEMBLY.................... 4-56
REMOVING THE BEARING..................................................................... 4-56
CHECKING THE REAR SHOCK ABSORBER ASSEMBLY .................... 4-57
CHECKING THE CONNECTING ARM AND RELAY ARM ...................... 4-57
INSTALLING THE RELAY ARM............................................................... 4-57
INSTALLING THE REAR SHOCK ABSORBER ASSEMBLY .................. 4-58
SWINGARM.................................................................................................... 4-60
REMOVING THE SWINGARM................................................................. 4-61
REMOVING THE BEARING..................................................................... 4-61
CHECKING THE SWINGARM ................................................................. 4-61
INSTALLING THE SWINGARM ............................................................... 4-62
CHAIN DRIVE................................................................................................. 4-63
REMOVING THE DRIVE CHAIN.............................................................. 4-64
CHECKING THE DRIVE CHAIN .............................................................. 4-64
CHECKING THE DRIVE SPROCKET...................................................... 4-65
CHECKING THE REAR WHEEL SPROCKET ......................................... 4-65
INSTALLING THE DRIVE CHAIN ............................................................ 4-65

FRONT WHEEL
4-6
3. Install:
• Collar “1”
TIP
Apply the lithium soap base grease on the oil
seal lip.
EAS1SM5128INSTALLING THE FRONT WHEEL
1. Install:
• Front wheel
TIP
Install the brake disc “1” between the brake
pads “2” correctly.
2. Install:
• Front wheel axle “1”
TIP
Apply the lithium soap base grease to the front
wheel axle.3. Tighten:
• Front wheel axle nut “1”
ECA14140
NOTICE
Before tightening the front wheel axle nut,
push down hard on the handlebar(s) several
times and check if the front fork rebounds
smoothly.
4. Tighten:
• Front wheel axle pinch bolt “1”
1
LS
Front wheel axle nut
115 Nm (11.5 m·kgf, 83 ft·lbf)
Front wheel axle pinch bolt
21 Nm (2.1 m·kgf, 15 ft·lbf)
T R..
1
T R..
1 1