2012 YAMAHA YZ250F Owners Manual

3-7
ENGINE
3. Radiator cap
2. Apply the specified pressure.
3. Inspect:
• Pressure
Impossible to maintain the speci-
fied pressure for 10 seconds→
Replace.
CHECKING THE COOLING
SYSTEM
1. Inspect:
• Coolant level
2. Attach:
• Radiator cap tester "1" and adapt-
er "2"
3. Apply the specified pressure.
• Do not apply pressure more than
specified pressure.
• Radiator should be filled fully.
4. Inspect:
• Pressure
Impossible to maintain the speci-
fied pressure for 10 seconds→
Repair.
•Radiator "1"
• Radiator hose joint "2"
Coolant leakage→Repair or re-
place.
• Radiator hose "3"
Swelling→Replace.ADJUSTING THE CLUTCH LEVER
POSITION
1. Adjust:
• Clutch lever position
Clutch lever position adjustment
steps:
a. Loosen the locknuts "1".
b. Turn the adjusting bolt "2" until the
clutch lever position "a" is in the
desired position .
c. Tighten the locknuts.
2. Adjust:
• Clutch cable free play
Refer to "ADJUSTING THE
CLUTCH CABLE FREE PLAY".
ADJUSTING THE CLUTCH CABLE
FREE PLAY
1. Check:
• Clutch lever free play "a"
Out of specification→Adjust.
2. Adjust:
• Clutch lever free play
Clutch lever free play adjustment
steps:
a. Loosen the locknuts "1".
b. Turn the adjuster "2" until free
play "a" is within the specified lim-
its.
c. Tighten the locknuts.
• Before adjustment, expose the ad-
juster by moving the boot "3" and
cap "4" away.
• Make minute adjustment on the le-
ver side using the adjuster "5".
• After adjustment, check proper op-
eration of clutch lever.
3. Install:
•Cap "1"
• Boot "2"
Place the tip "a" of the cap in the boot.
ADJUSTING THE THROTTLE GRIP
FREE PLAY
1. Check:
• Throttle grip free play "a"
Out of specification→Adjust. Radiator cap opening
pressure:
110 kPa (1.1 kg/cm
2,
15.6 psi)
Radiator cap tester:
YU-24460-01/90890-
01325
Radiator cap tester
adapter:
YU-33984/90890-01352
Standard pressure:
180 kPa (1.8 kg/cm
2,
25.6 psi)
Locknut:
5 Nm (0.5 m•kg, 3.6
ft•lb)
Clutch lever free play "a"
:
7–12 mm (0.28–0.47 in)
Locknut:
4 Nm (0.4 m•kg, 2.9
ft•lb)
Throttle grip free play
"a":
3–5 mm (0.12–0.20 in)

3-8
ENGINE
2. Adjust:
• Throttle grip free play
Adjustment steps:
a. Slide the adjuster cover.
b. Loosen the locknut "1".
c. Turn the adjuster "2" until the
specified free play is obtained.
d. Tighten the locknut.
Prior to adjusting throttle grip free
play, the engine idling speed should
be adjusted.
After adjusting the throttle grip
free play, turn the handlebar to the
right and to the left to ensure that
this does not cause the engine
idling speed to change.
LUBRICATING THE THROTTLE
1. Remove:
• Cover (throttle cable cap) "1"
• Cover (grip cap) "2"
• Throttle grip cap "3"
2. Apply:
• Lithium soap base grease
On the throttle cable end "a".3. Install:
• Throttle grip cap
• Screw (throttle grip cap)
• Cover (grip cap)
• Cover (throttle cable cap)
ADJUSTING THE HOT STARTER
LEVER FREE PLAY
1. Check:
• Hot starter lever free play "a"
Out of specification→Adjust.
2. Adjust:
• Hot starter lever free play
Hot starter lever free play adjust-
ment steps:
a. Loosen the locknut "1".
b. Turn the adjuster "2" until free
play "a" is within the specified lim-
its.
c. Tighten the locknut.
After adjustment, check proper oper-
ation of hot starter.
CLEANING THE AIR FILTER
ELEMENT
Proper air filter maintenance is the
biggest key to preventing premature
engine wear and damage.
Never run the engine without the
air filter element in place; this
would allow dirt and dust to enter
the engine and cause rapid wear
and possible engine damage.
1. Remove:
• Seat
• Fitting bolt "1"
• Washer "2"
• Air filter element "3"
• Air filter guide "4"
2. Clean:
• Air filter element
Clean them with solvent.
After cleaning, remove the remaining
solvent by squeezing the element.
• Do not twist the element when
squeezing the element.
• Leaving too much of solvent in
the element may result in poor
starting.
3. Inspect:
• Air filter element
Damage→Replace.
4. Apply:
• Foam-air-filter oil or equivalent oil
to the element
Squeeze out the excess oil. Element
should be wet but not dripping.
5. Install:
• Air filter guide "1"
Align the projection "a" on filter guide
with the hole "b" in air filter element.
Screw (throttle grip cap):
4 Nm (0.4 m•kg, 2.9
ft•lb)
Hot starter lever free play
"a":
3–6 mm (0.12–0.24 in)
Locknut:
4 Nm (0.4 m•kg, 2.9
ft•lb)

3-9
ENGINE
6. Apply:
• Lithium soap base grease
On the matching surface "a" on air
filter element.
7. Install:
• Air filter element "1"
• Washer
• Fitting bolt
Align the projection "a" on filter guide
with the hole "b" in air filter case.
CHECKING THE ENGINE OIL
LEVEL
1. Start the engine, warm it up for
several minutes, and then turn off
the engine and wait for five min-
utes.
2. Place the machine on a level
place and hold it up on upright po-
sition by placing the suitable
stand under the engine.
3. Inspect:
• Oil level
The engine oil level should be be-
tween the minimum level mark "a"
and maximum level mark "b".
Below the minimum level mark →
Add the recommended engine oil
to the proper level.
• Engine oil also lubricates the
clutch and the wrong oil types or
additives could cause clutch
slippage. Therefore, do not add
any chemical additives or use en-
gine oils with a grade of CD or
higher and do not use oils la-
beled "ENERGY CONSERVING
II".
• Do not allow foreign materials to
enter the crankcase.
4. Install:
• Oil tank cap
5. Start the engine and let it warm up
for several minutes.
6. Turn off the engine and inspect
the oil level once again.
Wait a few minutes until the oil settles
before inspecting the oil level.
CHANGING THE ENGINE OIL
1. Start the engine and warm it up
for several minutes, and then turn
off the engine and wait for five
minute.
2. Place the machine on a level
place and hold it on upright posi-
tion by placing the suitable stand
under the engine.
3. Place a suitable container under
the engine.4. Remove:
• Lower engine guard "1"
• Bolt (oil tank) "2"
• Washer "3"
• Oil filler cap "4"
• Oil tank drain bolt "5"
• Crankcase oil drain bolt "6"
• Oil filter element drain bolt "7"
Drain the crankcase and oil tank
of its oil.
5. Remove:
• Oil hose clamp "1"
• Bolt (oil hose)
• Oil hose "2"
• Oil strainer "3"
6. Inspect:
• Oil strainer
Clogged→Blow.
7. If the oil filter is to be replaced dur-
ing this oil change, remove the fol-
lowing parts and reinstall them. Fitting bolt:
2 Nm (0.2 m•kg, 1.4
ft•lb)
Recommended brand:
YAMALUBE
Recommended engine
oil type
SAE10W-30, SAE 10W-
40, SAE 10W-50, SAE
15W-40, SAE 20W-40 or
SAE 20W-50
Recommended engine
oilgrade
API service SG type or
higher, JASO standard
MA

3-10
ENGINE
Replacement steps:
a. Remove the oil filter element cov-
er "1" and oil filter element "2".
b. Check the O-rings "3", if cracked
or damaged, replace them with a
new one.
c. Install the oil filter element and oil
filter element cover.
8. Install:
• O-ring "1"
• Oil strainer "2"
• Oil hose
• Bolt (oil hose)
• Oil hose clamp
9. Install:
• Copper washer
• Oil filter element drain bolt
• Crankcase oil drain bolt• Oil tank drain bolt
• Lower engine guard
10. Fill:
• Engine oil
11. Check:
• Oil leakage
12. Install:
• Oil filler cap
• Washer (oil tank)
• Bolt (oil tank)
13. Check:
• Engine oil level
CHECKING THE OIL PRESSURE
1. Check:
• Oil pressure
Checking steps:
a. Slightly loosen the oil pressure
check bolt "1".
b. Start the engine and keep it idling
until oil starts to seep from the oil
pressure check bolt. If no oil
comes out after one minute, turn
the engine off so it will not seize.
c. Check oil passages and oil pump
for damage or leakage.
d. Start the engine after solving the
problem(s) and recheck the oil
pressure.e. Tighten the oil pressure check
bolt.
ADJUSTING THE PILOT SCREW
1. Adjust:
• Pilot screw "1"
Adjustment steps:
To optimize the fuel flow at a smaller
throttle opening, each machine's pilot
screw has been individually set at the
factory. Before adjusting the pilot
screw, turn it in fully and count the
number of turns. Record this number
as the factory-set number of turns
out.
a. Turn in the pilot screw until it is
lightly seated.
b. Turn out the pilot screw by the
factory-set number of turns.
ADJUSTING THE ENGINE IDLING
SPEED
1. Start the engine and thoroughly
warm it up.
2. Adjust:
• Engine idling speed
Adjustment steps:
a. Adjust the pilot screw.
Refer to "ADJUSTING THE PI-
LOT SCREW" section. Oil filter element cover:
10 Nm (1.0 m•kg, 7.2
ft•lb)
Oil strainer:
9 Nm (0.9 m•kg, 6.5
ft•lb)
Bolt (oil hose):
8 Nm (0.8 m•kg, 5.8
ft•lb)
Oil hose clamp:
2 Nm (0.2 m•kg, 1.4
ft•lb)
Oil filter element drain
bolt:
10 Nm (1.0 m•kg, 7.2
ft•lb)
Crankcase oil drain bolt:
20 Nm (2.0 m•kg, 14
ft•lb)
Oil tank drain bolt:
18 Nm (1.8 m•kg, 13
ft•lb)
Lower engine guard:
10 Nm (1.0 m•kg, 7.2
ft•lb)
Oil quantity:
Periodic oil change:
0.95 L (0.84 Imp qt,
1.00 US qt)
With oil filter replace-
ment:
1.05 L (0.92 Imp qt,
1.11 US qt)
Total amount:
1.20 L (1.06 Imp qt,
1.27 US qt)
Bolt (oil tank):
4 Nm (0.4 m•kg, 2.9
ft•lb)
Oil pressure check bolt:
10 Nm (1.0 m•kg, 7.2
ft•lb)
Pilot screw (example):
2 turns out
*2-1/4 turns out
* For EUROPE

3-11
ENGINE
b. Turn the throttle stop screw "1"
until the specified engine idling
speed.
Using a digital engine tachometer for
idle speed adjustment, detect the en-
gine idling speed by bringing the
sensing element "c" of the engine ta-
chometer close to the ignition coil "2".
ADJUSTING THE VALVE
CLEARANCE
• This section is intended for those
who have basic knowledge and skill
concerning the servicing of Yama-
ha motorcycles (e.g., Yamaha deal-
ers, service engineers, etc.) Those
who have little knowledge and skill
concerning servicing are requested
not to undertake inspection, adjust-
ment, disassembly, or reassembly
only by reference to this manual. It
may lead to servicing trouble and
mechanical damage.
• The valve clearance should be ad-
justed when the engine is cool to
the touch.
• The piston must be at Top Dead
Center (T.D.C.) on compression
stroke to check or adjust the valve
clearance.
1. Remove:
•Seat
•Fuel tank
Refer to "SEAT, FUEL TANK
AND SIDE COVERS" section in
the CHAPTER 4.
2. Remove:
• Spark plug
• Cylinder head cover
Refer to "CAMSHAFTS" section
in the CHAPTER 4.
3. Remove:
• Timing mark accessing screw "1"
• Crankshaft end accessing screw
"2"
• O-ring
4. Check:
• Valve clearance
Out of specification→Adjust.
Checking steps:
a. Turn the crankshaft counterclock-
wise with a wrench.
b. Align the T.D.C. mark "a" on the
rotor with the align mark "b" on the
crankcase cover when piston is at
T.D.C. on compression stroke.
In order to be sure that the piston is at
Top Dead Center, the punch mark "c"
on the exhaust camshaft and the
punch mark "d" on the intake cam-
shaft must align with the cylinder
head surface, as shown in the illustra-
tion.
c. Measure the valve clearance "e"
using a feeler gauge "1".
Record the measured reading if the
clearance is incorrect.
5. Adjust:
• Valve clearance
Adjustment steps:
a. Remove the camshaft (intake and
exhaust).
Refer to "CAMSHAFTS" section
in the CHAPTER 4.
b. Remove the valve lifters "1" and
the pads "2".
• Place a rag in the timing chain
space to prevent pads from falling
into the crankcase.
• Identity each valve lifter and pad
position very carefully so that they
can be reinstalled in their original
place.
To increase idle speed→Turn the
throttle stop screw "1" in "a".
To decrease idle speed→Turn the
throttle stop screw "1" out "b".
Engine idling speed:
1,900–2,100 r/min
Valve clearance (cold):
Intake valve:
0.12–0.17 mm
(0.0047–0.0067 in)
Exhaust valve:
0.17–0.22 mm
(0.0067–0.0087 in)

3-12
ENGINE
c. Select the proper pad using the
pad selecting table.
The thickness "a" of each pad is indi-
cated in hundredths of millimeters on
the pad upper surface.
d. Round off the last digit of the in-
stalled pad number to the nearest
increment.
EXAMPLE:
Installed pad number = 148
Rounded off value = 150
Pads can only be selected in 0.05
mm increments.
e. Locate the rounded-off value and
the measured valve clearance in
the chart "PAD SELECTION TA-
BLE". The field where these two
coordinates intersect shows the
new pad number to use.
Use the new pad number only as a
guide when verifying the valve clear-
ance adjustment.
f. Install the new pads "3" and the
valve lifters "4".
• Apply the engine oil on the valve lift-
ers.
• Apply the molybdenum disulfide oil
on the valve stem ends.
• Valve lifter must turn smoothly
when rotated with a finger.
• Be careful to reinstall valve lifters
and pads in their original place.
g. Install the camshafts (exhaust
and intake).
Refer to "CAMSHAFTS" section
in the CHAPTER 4.
Pad rangePad Availabili-
ty: 25 incre-
ments
No.
120–N
o. 2401.20
mm–2.
40 mmPads are avail-
able in 0.05 mm
increments
Last digit of pad
numberRounded valve
0, 1 or 2 0
4, 5 or 6 5
8 or 9 10

3-13
ENGINE
INTAKE
EXHAUST
120 125 130 135 140 145 150 155 160 165 170175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.00 - 0.01
0.02 - 0.06
0.07 - 0.11
0.12 - 0.17
0.18 - 0.22
0.23 - 0.27
0.28 - 0.32
0.33 - 0.37
0.38 - 0.42
0.43 - 0.47
0.48 - 0.52
0.53 - 0.57
0.58 - 0.62
0.63 - 0.67
0.68 - 0.72
0.73 - 0.77
0.78 - 0.82
0.83 - 0.87
0.88 - 0.92
0.93 - 0.97
0.98 - 1.02
1.03 - 1.07
1.08 - 1.12
1.13 - 1.17
1.18 - 1.22
1.23 - 1.27
1.28 - 1.32
120 125 130 135 140 145 150 155160 165 170 175 180 185 190 195 200 205 210 215 220 225 230120 125 130 135 140 145
150 155 160 165
170 175 180 185 190 195 200 205 210 215 220 225 230 235
125130135140145150155160165170175180 185 190 195 200 205 210 215 220 225 230 235240
130135140145150155160165170175180185 190 195 200 205 210 215 220 225 230 235240
135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235240
140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235240
145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235240
150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235240
155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235240
160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235240
165 170 175 180 185 190 195 200 205 210 215 220 225 230 235240
170 175 180 185 190 195 200 205 210 215 220 225 230 235240
175 180 185 190 195 200 205 210 215 220 225 230 235240
180 185 190 195 200 205 210 215 220 225 230 235 240
185 190 195 200 205 210 215 220 225 230 235
240
190 195 200 205 210 215 220 225 230 235240
195 200 205 210 215 220 225 230 235240
200 205 210 215 220 225 230 235240
205 210 215 220 225 230 235240
210 215 220 225 230 235240
215 220 225 230 235240
220 225 230 235240
225 230 235240
230 235240
235240
240
150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225
120 125 130 135 140 145
1.33 - 1.37
VALVE CLEARANCE (cold):
0.12 - 0.17 mm
Example: Installed is 175
Measured clearance is 0.23 mm
Replace 175 pad with 185 pad
MEASURED
CLEARANCEINSTALLED PAD NUMBER
STANDARD CLEARANCE
Pad number: (example)
Pad No. 175 = 1.75 mm
Pad No. 185 = 1.85 mm
MEASURED
CLEARANCEINSTALLED PAD NUMBER
120 125 130 135 140 145 150 155 160 165 170
175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.00 - 0.04 120 125 130 135 140 145 150 155
160 165 170 175 180 185 190 195 200 205 210 215 220 225
0.05 - 0.09
120 125 130 135 140 145 150 155 160165 170 175 180 185 190 195 200 205 210 215 220 225 230
0.10 - 0.16
120125130135140145150155160165170 175 180 185 190 195 200 205 210 215 220 225230235
0.17 - 0.22STANDARD CLEARANCE
0.23 - 0.25 125 130 135 140 145 150 155 160 165 170 175
180 185 190 195 200 205 210 215 220 225230235240
0.26 - 0.30130135140145150155160165170175180185 190 195 200 205 210 215 220 225230235240
0.31 - 0.35 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225230235240
0.36 - 0.40 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225230235240
0.41 - 0.45 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225230235240
0.46 - 0.50 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225230235240
0.51 - 0.55 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225230235240
0.56 - 0.60 160 165 170 175 180 185 190 195 200 205 210 215 220 225230235240
0.61 - 0.65 165 170 175 180 185 190 195 200 205 210 215 220 225230235240
0.66 - 0.70 170 175 180 185 190 195 200 205 210 215 220 225230235240
0.71 - 0.75 175 180 185 190 195 200 205 210 215 220 225230235240
0.76 - 0.80 180 185 190 195 200 205 210 215 220 225230235240
0.81 - 0.85 185 190 195 200 205 210 215 220 225230235240
VALVE CLEARANCE (cold):
0.17 - 0.22 mm
Example: Installed is 175
Measured clearance is 0.27 mm
Replace 175 pad with 185 pad
Pad number: (example)
Pad No. 175 = 1.75 mm
Pad No. 185 = 1.85 mm0.86 - 0.90 190 195 200 205 210 215 220 225230235240
0.91 - 0.95 195 200 205 210 215 220 225230235240
0.96 - 1.00 200 205 210 215 220 225230235240
1.01 - 1.05 205 210 215 220 225230235240
1.06 - 1.10 210 215 220 225230235240
1.11 - 1.15 215 220 225230235240
1.16 - 1.20 220 225230235240
1.21 - 1.25 225230235240
1.26 - 1.30 230235240
1.31 - 1.35 235240
1.36 - 1.40 240

3-14
CHASSIS
CHASSIS
BLEEDING THE HYDRAULIC
BRAKE SYSTEM
Bleed the brake system if:
• The system has been disassem-
bled.
• A brake hose has been loosened
or removed.
• The brake fluid is very low.
• The brake operation is faulty.
A dangerous loss of braking per-
formance may occur if the brake
system is not properly bled.
1. Remove:
• Brake master cylinder cap
• Diaphragm
• Reservoir float (front brake)
• Protector (rear brake)
2. Bleed:
• Brake fluid
Air bleeding steps:
a. Add proper brake fluid to the res-
ervoir.
b. Install the diaphragm. Be careful
not to spill any fluid or allow the
reservoir to overflow.
c. Connect the clear plastic tube "2"
tightly to the caliper bleed screw
"1".
A. Front
B. Rear
d. Place the other end of the tube
into a container.
e. Slowly apply the brake lever or
pedal several times.
f. Pull the lever in or push down on
the pedal. Hold the lever or pedal
in position.
g. Loosen the bleed screw and allow
the lever or pedal to travel to-
wards its limit.h. Tighten the bleed screw when the
lever or pedal limit has been
reached; then release the lever or
pedal.
i. Repeat steps (e) to (h) until of the
air bubbles have been removed
from the system.
If bleeding is difficult, it may be nec-
essary to let the brake fluid system
stabilize for a few hours. Repeat the
bleeding procedure when the tiny
bubbles in the system have disap-
peared.
j. Add brake fluid to the level line on
the reservoir.
Check the operation of the brake
after bleeding the brake system.
3. Install:
• Protector (rear brake)
• Reservoir float (front brake)
• Diaphragm
• Brake master cylinder cap
ADJUSTING THE FRONT BRAKE
1. Check:
• Brake lever position "a"
2. Remove:
• Brake lever cover
3. Adjust:
• Brake lever position
Brake lever position adjustment
steps:
a. Loosen the locknut "1".b. Turn the adjusting bolt "2" until the
lever position "a" is within speci-
fied position.
c. Tighten the locknut.
Be sure to tighten the locknut, as it
will cause poor brake perfor-
mance.
4. Install:
• Brake lever cover
ADJUSTING THE REAR BRAKE
1. Check:
• Brake pedal height "a"
Out of specification→Adjust.
2. Adjust:
• Brake pedal height
Pedal height adjustment steps:
a. Loosen the locknut "1".
b. Turn the adjusting nut "2" until the
pedal height "a" is within specified
height.
c. Tighten the locknut.
• Adjust the pedal height between
the maximum "A" and the mini-
mum "B" as shown. (In this ad-
justment, the bolt "3" end "b"
should protrude out of the
threaded portion "4" but not be
less than 2 mm (0.08 in) "c" away
from the brake pedal "5").
• After the pedal height adjust-
ment, make sure that the rear
brake does not drag.
Bleed screw:
6 Nm (0.6 m•kg, 4.3
ft•lb)
Brake lever position "a":
Standard posi-
tionExtent of ad-
justment
95 mm (3.74 in)86–105 mm
(3.39–4.13 in)
Locknut:
5 Nm (0.5 m •kg, 3.6
ft•lb)
Brake pedal height "a":
Zero mm (Zero in)