2014 YAMAHA YZ250F lock

ENGINE
3-18
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a. Turn the crankshaft counterclockwise with a
wrench.
b. Align the top dead center (TDC) mark “a” on
the rotor with the alignment mark “b” on the
crankcase cover.
TIP
Check that the alignment mark “c” on the cam-
shaft sprocket and the alignment mark “d” on
the intake camshaft sprocket are aligned with
the edge of the cylinder head.
c. Measure the valve clearance “e” using a
thickness gauge “1”.
TIP
Record the measured reading if the clearance
is incorrect.
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5. Adjust:
• Valve clearance
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a. Remove the camshaft (intake and exhaust).
Refer to “CAMSHAFT” on page 5-11.
b. Remove the valve lifter “2” and the adjusting
pad “3” with a valve lapper “1”.
TIP
• Place a cloth in the timing chain space to pre-
vent adjusting pads from falling into the crank-
case.
• Identity each valve lifter and adjusting pad po-
sition very carefully so that they can be rein-
stalled in their original place.
b
a
dc
ee
Valve lapper
90890-04101
Valve lapping tool
YM-A8998
1
1
32

CHASSIS
3-22
EAS1SM1091CHECKING THE BRAKE HOSE
1. Check:
• Brake hose “1”
Cracks/damage/wear  Replace.
2. Check:
• Brake hose clamp
Loose Connection  Tighten the clamp bolt.
3. Stand the vehicle upright and apply the front
brake and the rear brake several times.
4. Check:
• Brake hoses
Brake fluid leaks  Replace the damaged
brake hose.
Refer to “FRONT BRAKE” on page 4-11.
Refer to “REAR BRAKE” on page 4-21.
EAS1SM1092ADJUSTING THE FRONT BRAKE
1. Check:
• Brake lever position “a”2. Remove:
• Brake lever cover
3. Adjust:
• Brake lever position
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a. Loosen the locknut “1”.
b. Turn the adjusting bolt “2” in direction “a” or
“b” until the specified brake lever position is
obtained.
c. Tighten the locknut.
EWA13050
WARNING
A soft or spongy feeling in the brake lever
can indicate the presence of air in the brake
system. Before running, bleed the brake
system. Air in the brake system will cause
braking performance to be reduced.
ECA13490
NOTICE
After adjusting the brake lever position,
make sure that there is no brake drag.
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4. Install:
• Brake lever cover
A. Front
B. Rear
Brake lever position
95 mm (3.74 in)
Extent of adjustment
86–105 mm (3.39–4.13 in)
1
1
Direction “a”
Brake lever position is increased.
Direction “b”
Brake lever position is decreased.
Locknut
5 Nm (0.5 m·kgf, 3.6 ft·lbf)
a
b
T R..

CHASSIS
3-23
EAS1SM1093ADJUSTING THE REAR BRAKE
1. Check:
• Brake pedal position “a”
(distance from the top of the rider footrest to
the top of the brake pedal)
Out of specification  Regulate.
2. Adjust:
• Brake pedal position
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a. Loosen the locknut “1”.
b. Turn the adjusting bolt “2” in direction “a” or
“b” until the specified brake pedal position is
obtained.
c. Tighten the locknut.
EWA1DX1001
WARNING
A soft or spongy feeling in the brake pedal
can indicate the presence of air in the brake
system. Before running, bleed the brake
system. Air in the brake system will cause
braking performance to be reduced.
ECA13510
NOTICE
After adjusting the brake pedal position,
make sure that there is no brake drag.
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EAS1SM1094CHECKING THE FRONT BRAKE PADS
1. Measure:
• Brake pad thickness “a”
Out of specification  Replace as a set.
TIP
The pads worn up to the indicator “b” grooves
mean that the brake pad thickness limit is
reached.
2. Replace:
• Brake pads
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a. Remove the pad pin plug “1”. Brake pedal position
0.0 mm (0.00 in)
Direction “a”
Brake pedal is raised.
Direction “b”
Brake pedal is lowered.
Locknut
6 Nm (0.6 m·kgf, 4.3 ft·lbf)1 2
a
b
T R..
Brake pad lining thickness (inner)
4.4 mm (0.17 in)
Limit
1.0 mm (0.04 in)
Brake pad lining thickness (outer)
4.4 mm (0.17 in)
Limit
1.0 mm (0.04 in)
a
b
a
1

CHASSIS
3-27
EWA13090
WARNING
• Use only the designated brake fluid. Other
brake fluids may cause the rubber seals to
deteriorate, causing leakage and poor
brake performance.
• Refill with the same type of brake fluid that
is already in the system. Mixing brake flu-
ids may result in a harmful chemical reac-
tion, leading to poor brake performance.
• When pouring the brake fluid, be careful
that water does not enter the reservoir.
Water will significantly lower the boiling
point of the brake fluid and could cause
vapor lock.
ECA13540
NOTICE
Immediately wipe off the spilled brake fluid
to avoid damage to painted surfaces or
plastic parts.
EAS1SM1098ADJUSTING THE DRIVE CHAIN SLACKECA13550
NOTICE
A drive chain that is too tight will overload
the engine and other vital parts, and one
that is too loose can skip and damage the
swingarm or cause an accident. Therefore,
keep the drive chain slack within the speci-
fied limits.
1. Use a suitable stand to raise the rear wheel
off the ground.
EWA13120
WARNING
Securely support the vehicle so that there is
no danger of it falling over.
2. Shift the transmission into the neutral posi-
tion.
3. Pull the drive chain up above the drive chain
guide installation bolt with a force of about
50 N (5.0 kgf, 36 lbf).
4. Check:
• Drive chain slack “a”
Out of specification  Regulate.
TIP
Measure drive chain slack between the drive
chain guide and the bottom of the chain as
shown.5. Adjust:
• Drive chain slack
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a. Loosen the wheel axle nut “1”.
b. Loosen both locknuts “2”.
c. Turn the drive chain puller “3” in direction “a”
or “b” until the specified drive chain slack is
obtained.
TIP
• To maintain the proper wheel alignment, ad-
just both sides evenly.
• Push the rear wheel forward to make sure that
there is no clearance between the swingarm
end plates and the ends of the swingarm.
d. Tighten the locknut.
e. Tighten the wheel axle nut.
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Drive chain slack
50–60 mm (1.97–2.36 in)
Direction “a”
The drive chain slack decreases.
Direction “b”
The drive chain slack increases.
Locknut
21 Nm (2.1 m·kgf, 15 ft·lbf)
Wheel axle nut
135 Nm (13.5 m·kgf, 98 ft·lbf)
a
1
32
a
b
T R..
T R..

CHASSIS
3-30
EAS1SM1104CHECKING THE SWINGARM OPERATION
1. Check:
• Swingarm smooth action
• Swingarm free play
Refer to “SWINGARM” on page 4-60.
EAS1SM1105CHECKING 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 4-53.
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 4-53.
EAS1SM1106ADJUSTING THE REAR SHOCK ABSORB-
ER ASSEMBLY
Use a suitable stand to raise the rear wheel off
the ground.
EWA13120
WARNING
Securely support the vehicle so that there is
no danger of it falling over.
Spring preload
ECA13590
NOTICE
Do not turn the adjuster forcibly beyond its
adjusting range.1. Remove:
• Rear frame
Refer to “REAR SHOCK ABSORBER AS-
SEMBLY” on page 4-53.
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.
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.
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
3-31
e. Tighten the locknut.
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3. Install:
• Rear frame
Refer to “REAR SHOCK ABSORBER AS-
SEMBLY” on page 4-53.
Rebound damping force
ECA13590
NOTICE
Do not turn the adjuster forcibly beyond its
adjusting range.
1. Adjust:
• Rebound damping force
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a. Turn the adjuster “1” in the direction of “a” or
“b” to make an adjustment.
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High compression dampingECA13590
NOTICE
Do not turn the adjuster forcibly beyond its
adjusting range.
1. Adjust:
• High compression damping
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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
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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 1/3 turns.*
(USA)(CAN)
Turn it out by 1 1/8 turns.*
(EUR)(JPN)(AUS)(NZL)(ZAF)
Minimum
Turn it out by two turns.*
* With the adjuster fully turned
a
b
1

ELECTRICAL SYSTEM
3-35
EAS1SM1114
ELECTRICAL SYSTEM
EAS1SM1115CHECKING THE SPARK PLUG
1. Remove:
• Seat
• Air scoop (left/right)
Refer to “GENERAL CHASSIS” on page 4-
1.
• Fuel tank “1”
Refer to “FUEL TANK” on page 7-1.
ECA1DX1001
NOTICE
Do not use too much force to pull the hose.
TIP
Remove the fuel tank, turn this 180 ° clockwise,
and put it in the frame “2” as shown.
2. Remove:
• Spark plug cap
• Spark plug
Refer to “CAMSHAFT” on page 5-11.
ECA13330
NOTICE
In order not to allow the dirt accumulated
around the spark plug to drop from the
spark plug hole into the cylinder, clean it be-
fore removing the spark plug.
3. Check:
• Spark plug type
Wrong type  Replace.
4. Check:
• Electrode
Damage/wear  Replace the spark plug.
• Insulator
Abnormal color  Replace the spark plug.
Normal color is medium-to-light tan.5. Clean:
• Spark plug
(with a spark plug cleaner or a wire brush)
6. Measure:
• Spark plug gap “a”
Out of specification  Adjust the spark plug
gap.
7. Install:
• Spark plug
TIP
Before installing the spark plug, clean the spark
plug and gasket surface.
8. Install:
• Spark plug cap
• Fuel tank
• Air scoop (left/right)
• Seat
• Side cover (left/right)
Refer to “GENERAL CHASSIS” on page 4-
1.
EAS1SM1116CHECKING THE IGNITION TIMING
1. Remove:
• Timing mark accessing screw “1”
Manufacturer/model
NGK/LMAR8G
1
1
2
Spark plug gap
0.7–0.8 mm (0.028–0.031 in)
Spark plug
13 Nm (1.3 m·kgf, 9.4 ft·lbf)
T R..
1

REAR WHEEL
4-8
EAS1SM1129REMOVING THE REAR WHEEL
1. Use a suitable stand to raise the rear wheel
off the ground.
EWA13120
WARNING
Securely support the vehicle so that there is
no danger of it falling over.
2. Remove:
• Rear wheel axle nut “1”
3. Loosen:
• Locknut “2”
4. Tighten:
• Adjusting bolt “3”
5. Remove:
• Rear wheel axle
• Rear wheel
TIP
• Push the rear wheel forward and remove the
drive chain from the rear wheel sprocket.
• Do not depress the brake pedal with the rear
wheel removed.
EAS1SM1130CHECKING THE REAR WHEEL
1. Check:
• Rear wheel axle
• Rear wheel
• Bearing
• Oil seals
Refer to “CHECKING THE FRONT WHEEL”
on page 4-4.
2. Check:
•Tire (s)
• Rear wheel
Damage/wear  Replace.
Refer to “CHECKING THE TIRES” on page
3-32 and “CHECKING THE WHEELS” on
page 3-33.
3. Check:
• Spokes
Refer to “CHECKING THE FRONT WHEEL”
on page 4-4.4. Measure:
• Radial wheel runout
• Lateral wheel runout
Refer to “CHECKING THE FRONT WHEEL”
on page 4-4.
EAS1SM1131DISASSEMBLING THE REAR WHEEL
1. Remove:
• Oil seals
• Bearing
Refer to “DISASSEMBLING THE FRONT
WHEEL” on page 4-5.
EAS1SM1132CHECKING AND REPLACING THE REAR
WHEEL SPROCKET
1. Check:
• Rear wheel sprocket
More than 1/4 tooth wear “a”  Replace the
rear wheel sprocket and the drive sprocket
as a set.
Bent tooth  Replace the rear wheel
sprocket and the drive sprocket as a set.
2. Replace:
• Rear wheel sprocket
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a. Remove the self-locking nuts and the rear
wheel sprocket.
b. Clean the rear wheel drive hub with a clean
cloth, especially the surfaces that contact
the sprocket.
c. Install the new rear wheel sprocket.
3
12
Radial wheel runout limit
2.0 mm (0.08 in)
Lateral wheel runout limit
2.0 mm (0.08 in)
b. Correct
1. Drive chain roller
2. Rear wheel sprocket
Rear wheel sprocket self-locking
nut
42 Nm (4.2 m·kgf, 30 ft·lbf)
T R..