wheel YAMAHA YZ250F 2010 User Guide

3-4
MAINTENANCE INTERVALS
REAR SHOCK ABSORBERInspect and adjust ●●
Lube ●(After
rain
ride) ●Molybdenum disulfide grease
Replace spring seat ●Every one year
Retighten ●●
DRIVE CHAIN GUIDE AND
ROLLERS Inspect ●●
SWINGARM Inspect, lube and retighten ●● Molybdenum disulfide grease
RELAY ARM, CONNECTING
ROD Inspect, lube and retighten ●● Molybdenum disulfide grease
STEERING HEAD Inspect free play and retighten ●●
Clean and lube ●Lithium base grease
Replace bearing ●
TIRE, WHEELS Inspect air pressure, wheel run-
out, tire wear and spoke loose-
ness ●●
Retighten sprocket bolt ●●
Inspect bearings ●
Replace bearings ●
Lubricate ●Lithium base grease
THROTTLE, CONTROL CABLE Check routing and connection ●●
Lubricate ●● Yamaha cable lube or SAE 10W-40
motor oil
Inspect and clean (throttle ca-
ble) ●●
Inspect dirt and wear on the throttle
cable on the carburetor side.
HOT STARTER, CLUTCH LEVER Inspect free play ●
Item
After
break- in Every
race
(about 2.5
hours)
Every third
(about 7.5
hours) Every
fifth
(about 12.5
hours)
As re-
quired Remarks

3-5
PRE-OPERATION INSPECTION AND MAINTENANCE
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.
GENERAL INSPECTION AND MAINTENANCE
Item RoutinePage
Coolant Check that coolant is filled up to the radiator cap. Check the cool-
ing system for leakage. P.3-6 – 7
Fuel Check that a fresh gasoline is filled in the fuel tank. Check the fuel
line for leakage. P.1-13
Engine oil Check that the oil level is correct. Check the crankcase and oil line
for leakage.
P.3-9 – 10
Gear shifter and clutch Check that gears can be shifted correctly in order and that the
clutch operates smoothly. P.3-7
Throttle grip/Housing Check that the throttle grip operation and free play are correctly
adjusted. Lubricate the throttle grip and housing, if necessary. P.3-7 – 8
Brakes Check the play of front brake and ef fect of front and rear brake. P.3-14 – 16
Drive chain Check drive chain slack and alignment. Check that the drive chain
is lubricated properly.
P.3-17 – 18
Wheels Check for excessive wear and ti
re pressure. Check for loose
spokes and have no excessive play. P.3-20 – 21
Steering Check that the handlebar can be turned smoothly and have no ex-
cessive play. P.3-21 – 22
Front forks and rear shock
absorber Check that they operate smooth
ly and there is no oil leakage.
P.3-18 – 20
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 pipe Check that the exhaust pipe is tightly mounted and has no cracks. P.4-3 – 4
Rear wheel sprocket Check that the rear whee l sprocket tightening bolt is not loose.P.3-17
Lubrication Check for smooth operation. Lubricate if necessary. P.3-23
Bolts and nuts Check the chassis and engine for loose bolts and nuts. P.1-15
Lead connectors Check that the CDI magneto, CDI
unit, and ignition coil are con-
nected tightly. P.1-7
Settings Is the machine set suitably for the
condition of the racing course
and weather or by taking into account the results of test runs be-
fore racing? Are inspection and maintenance completely done? P.7-1 – 10

3-16
CHASSIS
2. Replace:• Brake pad
Brake pad replacement steps:
a. Remove the protector "1" and pad pin plug "2".
b. Loosen the pad pin "3".
c. Remove the rear wheel "4" and brake caliper "5".
Refer to "FRONT WHEEL AND
REAR WHEEL" section in the
CHAPTER 5.
d. Remove the pad pin "6" and brake pads "7".
e. Connect the transparent hose "8" to the bleed screw "9" and place
the suitable container under its
end.
f. Loosen the bleed screw and push the brake caliper piston in.
Do not reuse the drained brake flu-
id.
g. Tighten the bleed screw. h. Install the brake pad "10" and pad
pin "11".
• Install the brake pads with their pro-jections "a" into the brake caliper re-
cesses "b".
• Temporarily tighten the pad pin at this point.
i. Install the brake caliper "12" and
rear wheel "13".
Refer to "FRONT WHEEL AND
REAR WHEEL" section in the
CHAPTER 5.
j. Tighten the pad pin "14".
k. Install the pad pin plug "15" and protector "16".
3. Inspect:• Brake fluid levelRefer to "CHECKING THE
BRAKE FLUID LEVEL" section. 4. Check:
• Brake pedal operationA softy or spongy feeling →Bleed
brake system.
Refer to "BLEEDING THE HY-
DRAULIC BRAKE SYSTEM" sec-
tion.
CHECKING THE REAR BRAKE
PAD INSULATOR
1. Remove: • Brake padRefer to "CHECKING AND RE-
PLACING THE REAR BRAKE
PADS" section.
2. Inspect:
• Rear brake pad insulator "1"Damage →Replace.
CHECKING THE BRAKE FLUID
LEVEL
1. Place the brake master cylinder so that its top is in a horizontal po-
sition.
2. Inspect: • Brake fluid level
Fluid at lower level →Fill up.
• Use only designated quality
brake fluid to avoid poor brake
performance.
• Refill with same type and brand of brake fluid; mixing fluids
could result in poor brake perfor-
mance.
• Be sure that water or other con- taminants do not enter master
cylinder when refilling.
• Clean up spilled fluid immediate- ly to avoid erosion of painted
surfaces or plastic parts.
a. Lower level
A. Front
B. Rear
Bleed screw:
6 Nm (0.6 m•kg, 4.3
ft•lb)
Pad pin:18 Nm (1.8 m•kg, 13
ft•lb)
Pad pin plug: 3 Nm (0.3 m•kg, 2.2
ft•lb)
Bolt (protector):
7 Nm (0.7 m•kg, 5.1
ft•lb)
Recommended brake flu-
id: DOT #4

3-17
CHASSIS
CHECKING THE SPROCKET
1. Inspect:• Sprocket teeth "a"Excessive wear →Replace.
Replace the drive sprocket, rear
wheel sprocket and drive chain as a
set.
CHECKING THE DRIVE CHAIN
1. Measure:
• Drive chain length (15 links) "a"Out of specification →Replace.
• While measuring the drive chain
length, push down on the drive
chain to increase its tension.
• Measure the length between drive
chain roller "1" and "16" as shown.
• Perform this measurement at two or three different places.
2. Remove:• Master link clip
•Joint "1"
• Drive chain "2" 3. Clean:
• Drive chainPlace it in kerosene, and brush off
as much dirt as possible. Then re-
move the drive chain from the ker-
osene and dry the drive chain.
4. Check: • Drive chain stiffness "a"
Clean and oil the drive chain and
hold as illustrated.
Stiff →Replace the drive chain.
5. Install: • Drive chain "1"
•Joint "2"
• Master link clip "3"
Be sure to install the master link
clip to the direction as shown.
a. Turning direction
6. Lubricate: • Drive chain ADJUSTING THE DRIVE CHAIN
SLACK
1. Elevate the rear wheel by placing
the suitable stand under the en-
gine.
2. Check: • Drive chain slack "a"
Above the seal guard installation
bolt.
Out of specification →Adjust.
Before checking and/or adjusting, ro-
tate the rear wheel through several
revolutions and check the slack sev-
eral times to find the tightest point.
Check and/or adjust the drive chain
slack with the rear wheel in this "tight
chain" position.
3. Adjust:
• Drive chain slack
Drive chain slack adjustment
steps:
a. Loosen the axle nut "1" and lock- nuts "2".
b. Adjust the drive chain slack by turning the adjusters "3".
c. Turn each adjuster exactly the same amount to maintain correct
axle alignment. (There are marks
"a" on each side of the drive chain
puller alignment.) NOTICE: Im-
proper drive chain slack will
overload the engine aswell as
other vital parts of the motorcy-
cle and can lead to chain slip-
page or breakage. To prevent
this from occurring, keep the
drive chain slack within the
specified limits.
Drive chain length (15
links):
: 242.9 mm
(9.563 in)
Drive chain lubricant:
SAE 10W-40 motor oil
or suitable chain lubri-
cants
Drive chain slack: 50–60 mm (2.0–2.4 in)
To tighten →Turn the adjuster "3"
counterclockwise.
To loosen →Turn the adjuster "3"
clockwise and push wheel for-
ward.

3-18
CHASSIS
A. Right
B. Left
Turn the adjuster so that the drive
chain is in line with the sprocket, as
viewed from the rear.
d. Tighten the axle nut while pushing down the drive chain.
e. Tighten the locknuts.
CHECKING THE FRONT FORK
1. Inspect: • Front fork smooth action
Operate the front brake and
stroke the front fork.
Unsmooth action/oil leakage →
Repair or replace.
CHECKING THE FRONT FORK
PROTECTOR GUIDE
1. Inspect: • Protector guide "1"Out of specification →Replacet.
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.
CLEANING THE FRONT FORK OIL
SEAL AND DUST SEAL
1. Remove:
•Protector
• Dust seal "1"
Use a thin screw driver, and be care-
ful not to damage the inner fork tube
and dust seal.
2. Clean:• Dust seal "a"
• Oil seal "b"
• Clean the dust seal and oil seal af-
ter every run.
• Apply the lithium soap base grease on the inner tube.
RELIEVING THE FRONT FORK
INTERNAL PRESSURE
If the front fork initial movement feels
stiff during a run, re lieve the front fork
internal pressure.
1. Elevate the front wheel by placing a suitable stand under the engine.
2. Remove the air bleed screw "1" and release the internal pressure
from the front fork.
3. Install: • Air bleed screw ADJUSTING THE FRONT FORK
REBOUND DAMPING FORCE
1. Adjust:
• Rebound damping forceBy turning the adjuster "1".
• STANDARD POSITION: This is the position which is back
by the specific number of clicks
from the fully turned-in position.
Do not force the adjuster past the
minimum or maximum extent of
adjustment. The adjuster may be
damaged.
Always adjust each front fork to
the same setting. Uneven adjust-
ment can cause poor handling and
loss of stability.
Axle nut: 135 Nm (13.5 m•kg, 98
ft•lb)
Locknut: 21 Nm (2.1 m•kg, 15
ft•lb)
Air bleed screw:
1 Nm (0.1 m•kg, 0.7
ft•lb)
Stiffer "a" →Increase the re-
bound damping force. (Turn
the adjuster "1" in.)
Softer "b" →Decrease the re-
bound damping force. (Turn
the adjuster "1" out.)
Extent of adjustment:
Maximum Minimum
Fully turned in
position 20 clicks out
(from maximum
position)
Standard position: 10 clicks out
* 9 clicks out
* Except for USA and CDN

3-19
CHASSIS
ADJUSTING THE FRONT FORK
COMPRESSION DAMPING FORCE
2. Adjust:• Compression damping force
By turning the adjuster "1".
• STANDARD POSITION: This is the position which is back
by the specific number of clicks
from the fully turned-in position.
Do not force the adjuster past the
minimum or maximum extent of
adjustment. The adjuster may be
damaged.
Always adjust each front fork to
the same setting. Uneven adjust-
ment can cause poor handling and
loss of stability.
CHECKING THE REAR SHOCK
ABSORBER
1. Inspect:• Swingarm smooth actionAbnormal noise/unsmooth action
→ Grease the pivoting points or
repair the pivoting points.
Damage/oil leakage →Replace. ADJUSTING THE REAR SHOCK
ABSORBER SPRING PRELOAD
1. Elevate the rear wheel by placing
the suitable stand under the en-
gine.
2. Remove: • Rear frame
3. Measure:
• Spring fitting length
The I.D. mark "a" is marked at the end
of the spring.
4. Adjust: • Spring preload
Adjustment steps:
a. Loosen the locknut "1".
b. Loosen the adjuster "2" until there is some clearance between the
spring and adjuster.
c. Measure the spring free length
"a".
d. Turn the adjuster "2".
• Be sure to remove all dirt and mud from around the locknut and adjust-
er before adjustment.
• The length of the spring (installed) changes 1.5 mm (0.06 in) per turn
of the adjuster.
Never attempt to tu rn the adjuster
beyond the maximum or minimum
setting.
e. Tighten the locknut.
5. Install: • Rear frame (upper)
• Rear frame (lower)
ADJUSTING THE REAR SHOCK
ABSORBER REBOUND DAMPING
FORCE
1. Adjust: • Rebound damping forceBy turning the adjuster "1".
Stiffer "a"
→Increase the com-
pression damping force. (Turn
the adjuster "1" in.)
Softer "b" →Decrease the com-
pression damping force. (Turn
the adjuster "1" out.)
Extent of adjustment:
Maximum Minimum
Fully turned in
position 20 clicks out
(from maximum
position)
Standard position: 8 clicks out
* 6 clicks out
* Except for USA and CDN
Standard fitti ng length:
I.D. MARK/Q'TY Length
Yellow/1 250 mm (9.84 in)
Stiffer →Increase the spring pre-
load. (Turn the adjuster "2" in.)
Softer →Decrease the spring pre-
load. (Turn the adjuster "2"
out.)
Extent of adjustment:
Maximum Minimum
Position in
which the
spring is turned
in 20 mm (0.79
in) from its free
length. Position in
which the
spring is turned
in 1.5 mm (0.06
in) from its free
length.
Locknut: 30 Nm (3.0 m•kg, 22
ft•lb)
Rear frame (upper): 32 Nm (3.2 m•kg, 23
ft•lb)
Rear frame (lower): 32 Nm (3.2 m•kg, 23
ft•lb)
Stiffer "a" →Increase the re-
bound damping force. (Turn
the adjuster "1" in.)
Softer "b" →Decrease the re-
bound damping force. (Turn
the adjuster "1" out.)

3-21
CHASSIS
CHECKING AND TIGHTENING THE
SPOKES
The following procedure applies to all
of the spokes.
1. Check:• SpokesBend/damage →Replace.
Loose spoke →Retighten.
Tap the spokes with a screw-
driver.
A tight spoke will emit a clear, ringing
tone; a loose spoke will sound flat.
2. Tighten: • Spokes
(with a spoke nipple wrench "1")
Be sure to retighten these spokes be-
fore and after break-in.
CHECKING THE WHEELS
1. Inspect:• Wheel runout
Elevate the wheel and turn it.
Abnormal runout → Replace. 2. Inspect:
• Bearing free playExist play →Replace.
CHECKING AND ADJUSTING THE
STEERING HEAD
1. Place a stand under the engine to raise the front wheel off the
ground. WARNING! Securely
support the vehicle so that
there is no danger of it falling
over.
2. Check: • Steering stemGrasp the bottom of the forks and
gently rock the fork assembly
back and forth.
Free play →Adjust steering head.
3. Check: • Steering smooth actionTurn the handlebar lock to lock.
Unsmooth action →Adjust steer-
ing ring nut.
4. Adjust: • Steering ring nut
Steering ring nut adjustment
steps:
a. Remove the number plate.
b. Remove the handlebar and upper
bracket. c. Loosen the steering ring nut "1"
using the steering nut wrench "2".
d. Tighten the steering ring nut "3" using steering nut wrench "4".
• Apply the lithium soap base grease on the thread of the steering stem.
• Set the torque wrench to the steer-
ing nut wrench so that they form a
right angle.
e. Loosen the steering ring nut one turn.
f. Retighten the steering ring nut us- ing the steering nut wrench.
Avoid over-tightening.
g. Check the steering stem by turn-ing it lock to lock. If there is any
binding, remove the steering stem
assembly and inspect the steer-
ing bearings.
Spoke nipple wrench:
YM-01521/90980-01521
Spokes: 3 Nm (0.3 m•kg, 2.2
ft•lb)
Steering nut wrench:YU-33975/90890-01403
Steering nut wrench: YU-33975/90890-01403
Steering ring nut (initial
tightening): 38 Nm (3.8 m•kg, 27
ft•lb)
Steering ring nut (final
tightening): 7 Nm (0.7 m•kg, 5.1
ft•lb)

4-44
KICK SHAFT AND SHIFT SHAFT
KICK SHAFT AND SHIFT SHAFT
REMOVING THE KICK SHAFT AND SHIFT SHAFTOrder Part name Q'ty Remarks Oil pump Refer to "OIL PUMP" section.
1 Kick idle gear 1
2 Kick shaft assembly 1 Refer to removal section.
3 Spring guide 1
4 Torsion spring 1
5 Ratchet wheel 1
6 Kick gear 1
7 Kick shaft 1
8 Washer 1
9 Shift pedal 1
10 Shift shaft 1
11 Collar 1
12 Torsion spring 1
13 Roller 1
14 Shift guide 1 Refer to removal section.
15 Shift lever assembly 1 Refer to removal section.
16 Shift lever 1

4-46
KICK SHAFT AND SHIFT SHAFT
REMOVING THE KICK SHAFT
ASSEMBLY
1. Remove:• Kick shaft assembly "1"
Unhook the torsion spring "2" from
the hole "a" in the crankcase.
REMOVING THE SHIFT GUIDE
AND SHIFT LEVER ASSEMBLY
1. Remove:• Bolt (shift guide)
• Shift guide "1"
• Shift lever assembly "2"
The shift lever assembly is disassem-
bled at the same time as the shift
guide.
REMOVING THE SEGMENT
1. Remove:
• Bolt (segment) "1"
• Segment "2"
Turn the segment counterclockwise
until it stops and loosen the bolt.
If the segment gets an impact, it
may be damaged. Take care not to
give an impact to the segment
when removing the bolt.
CHECKING THE KICK SHAFT AND
RATCHET WHEEL
1. Check:• Ratchet wheel "1" smooth move-
ment
Unsmooth movement →Replace.
• Kick shaft "2"
Wear/damage →Replace.
• Spring "3" Broken →Replace.
CHECKING THE KICK GEAR, KICK
IDLE GEAR AND RATCHET
WHEEL
1. Inspect: • Kick gear "1"
• Kick idle gear "2"
• Ratchet wheel "3"
• Gear teeth "a"
• Ratchet teeth "b"Wear/damage →Replace.
CHECKING THE SHIFT SHAFT
1. Inspect: • Shift shaft "1"
Bend/damage →Replace.
• Spring "2" Broken →Replace. CHECKING THE SHIFT GUIDE AND
SHIFT LEVER ASSEMBLY
1. Inspect:
• Shift guide "1"
• Shift lever "2"
•Pawl "3"
• Pawl pin "4"
• Spring "5"Wear/damage →Replace.
CHECKING THE STOPPER LEVER
1. Inspect: • Stopper lever "1"Wear/damage →Replace.
• Torsion spring "2"
Broken →Replace.
INSTALLING THE SEGMENT
1. Install: • Segment "1"
• Bolt (segment)
Align the notch "a" on the segment
with the pin "b" on the shift cam.
If the segment gets an impact, it
may be damaged. Take care not to
give an impact to the segment
when tightening the bolt.
Bolt (segment): 30 Nm (3.0 m•kg, 22
ft•lb)

4-47
KICK SHAFT AND SHIFT SHAFT
INSTALLING THE STOPPER
LEVER
1. Install:• Torsion spring "1"
• Stopper lever "2"
• Bolt (stopper lever) "3"
Align the stopper lever roller with the
slot on segment.
INSTALLING THE SHIFT GUIDE
AND SHIFT LEVER ASSEMBLY
1. Install:• Spring "1"
• Pawl pin "2"
•Pawl "3"To shift lever "4".
Apply the engine oil on the spring,
pawl pin and pawl.
2. Install:
• Shift lever assembly "1"To shift guide "2".
3. Install: • Shift lever assembly "1"
• Shift guide "2"
• The shift lever assembly is installed at the same time as the shift guide.
• Apply the engine oil on the bolt
(segment) shaft.
4. Install:• Bolt (shift guide) "1"
INSTALLING TH E SHIFT SHAFT
1. Install: • Roller "1"
• Collar "2"
• Torsion spring "3"
• Shift shaft "4"
Apply the engine oil on the roller and
shift shaft.
2. Install:• Shift pedal "1"
• Bolt (shift pedal) "2"
Install with the punch mark "a" on the
shift pedal in alignment with the
punch mark "b" on the shift shaft.
INSTALLING THE KICK SHAFT
ASSEMBLY
1. Install:• Kick gear "1"
• Washer "2"
• Circlip "3"
• Ratchet wheel "4"
• Spring "5"
• Washer "6"
• Circlip "7"
To kick shaft "8".
• Apply the molybdenum disulfide oil on the inner circumferences of the
kick gear and ratchet wheel.
• Align the punch mark "a" on the ratchet wheel with the punch mark
"b" on the kick shaft.
2. Install:• Torsion spring "1"To kick shaft "2".
Make sure the stopper "a" of the tor-
sion spring fits into the hole "b" on the
kick shaft.
3. Install:• Spring guide "1"
Slide the spring guide into the kick
shaft, make sure the groove "a" in the
spring guide fits on the stopper of the
torsion spring.
Bolt (stopper lever): 10 Nm (1.0 m•kg, 7.2
ft•lb)
Bolt (shift guide):
10 Nm (1.0 m•kg, 7.2
ft•lb)
Bolt (shift pedal): 12 Nm (1.2 m•kg, 8.7
ft•lb)