2010 YAMAHA YZ250F checking oil

CONTENTS
CHAPTER 1GENERAL
INFORMATION
LOCATION OF
IMPORTANT LABELS ..... 1-1
DESCRIPTION ................. 1-5
CONSUMER
INFORMATION................. 1-6
INCLUDED PARTS .......... 1-6
IMPORTANT
INFORMATION................. 1-6
CHECKING OF
CONNECTION .................. 1-7
SPECIAL TOOLS ............. 1-8
CONTROL
FUNCTIONS ................... 1-12
STARTING AND
BREAK-IN ...................... 1-13
TORQUE-CHECK
POINTS........................... 1-15
CLEANING AND
STORAGE ...................... 1-16
CHAPTER 2
SPECIFICATIONS
GENERAL
SPECIFICATIONS ............ 2-1
MAINTENANCE
SPECIFICATIONS ............ 2-3
TIGHTENING
TORQUES ...................... 2-10
LUBRICATION
DIAGRAMS .................... 2-16
CABLE ROUTING
DIAGRAM ....................... 2-18
CHAPTER 3 REGULAR
INSPECTION AND ADJUSTMENTS
MAINTENANCE
INTERVALS ...................... 3-1
PRE-OPERATION
INSPECTION AND
MAINTENANCE................ 3-5
ENGINE ............................ 3-6
CHASSIS ........................ 3-14
ELECTRICAL ................. 3-24
CHAPTER 4 ENGINE
SEAT, FUEL TANK AND
SIDE COVERS.................. 4-1
EXHAUST PIPE AND
SILENCER ........................ 4-3
RADIATOR ....................... 4-5
CARBURETOR................. 4-7
CAMSHAFTS.................. 4-14
CYLINDER HEAD........... 4-19
VALVES AND VALVE
SPRINGS ........................ 4-21
CYLINDER AND
PISTON ........................... 4-25
CLUTCH ......................... 4-29
OIL FILTER ELEMENT
AND WATER PUMP ....... 4-33
BALANCER .................... 4-38
OIL PUMP ....................... 4-40
KICK SHAFT AND
SHIFT SHAFT ................. 4-44
CDI MAGNETO............... 4-49
ENGINE REMOVAL ....... 4-51
CRANKCASE AND
CRANKSHAFT ............... 4-55
TRANSMISSION,
SHIFT CAM AND
SHIFT FORK................... 4-61
CHAPTER 5CHASSIS
FRONT WHEEL AND
REAR WHEEL ..................5-1
FRONT BRAKE AND
REAR BRAKE ..................5-6
FRONT FORK .................5-16
HANDLEBAR..................5-24
STEERING ......................5-28
SWINGARM ....................5-31
REAR SHOCK
ABSORBER ....................5-36
CHAPTER 6
ELECTRICAL
ELECTRICAL
COMPONENTS AND
WIRING DIAGRAM ...........6-2
IGNITION SYSTEM...........6-3
THROTTLE POSITION
SENSOR SYSTEM ...........6-6
CHAPTER 7 TUNING
ENGINE.............................7-1
CHASSIS ..........................7-6

1-7
CHECKING OF CONNECTION
4. During the machine disassembly, clean all parts and place them in
trays in the order of disassembly.
This will speed up assembly time
and help assure that all parts are
correctly reinstalled.
5. Keep away from fire.
ALL REPLACEMENT PARTS
1. We recommend to use Yamaha genuine parts for all replace-
ments. Use oil and/or grease rec-
ommended by Yamaha for
assembly and adjustment.
GASKETS, OIL SEALS AND O-
RINGS
1. All gaskets, oil seals, and O-rings should be replaced when an en-
gine is overhauled. All gasket sur-
faces, oil seal lips, and O-rings
must be cleaned.
2. Properly oil all mating parts and
bearings during reassembly. Ap-
ply grease to the oil seal lips.
LOCK WASHERS/PLATES AND
COTTER PINS
1. All lock washers/plates "1" and cotter pins must be replaced
when they are removed. Lock
tab(s) should be bent along the
bolt or nut flat(s) after the bolt or
nut has been properly tightened. BEARINGS AND OIL SEALS
1. Install the bearing(s) "1" and oil
seal(s) "2" with their manufactur-
er's marks or numbers facing out-
ward. (In other words, the
stamped letters must be on the
side exposed to view.) When in-
stalling oil seal(s), apply a light
coating of lightweight lithium base
grease to the seal lip(s). Oil the
bearings liberally when installing.
Do not use compressed air to spin
the bearings dry. This causes dam-
age to the bearing surfaces.
CIRCLIPS
1. All circlips should be inspected carefully before reassembly. Al-
ways replace piston pin clips after
one use. Replace distorted cir-
clips. When installing a circlip "1",
make sure that the sharp-edged
corner "2" is positioned opposite
to the thrust "3" it receives. See
the sectional view.
CHECKING OF
CONNECTION
Dealing with stains, rust, moisture,
etc. on the connector.
1. Disconnect:• Connector 2. Dry each terminal with an air
blower.
3. Connect and disconnect the con- nector two or three times.
4. Pull the lead to check that it will
not come off.
5. If the terminal comes off, bend up the pin "1" and reinsert the termi-
nal into the connector.
6. Connect: • Connector
The two connectors "click" together.
7. Check for continuity with a tester.
• If there in no continuity, clean the terminals.
• Be sure to perform the steps 1 to 7 listed above when checking the
wire harness.
• For a field remedy, use a contact re- vitalizer available on the market.
• Use the tester on the connector as
shown.

1-9
SPECIAL TOOLS
Radiator cap tester
YU-24460-01, 90890-01325
Radiator cap tester adapter
YU-33984, 90890-01352These tools are used for checking
the cooling system.
Steering nut wrench
YU-33975, 90890-01403 This tool is used when tighten the
steering ring nut to specification.
Cap bolt wrench
YM-01500, 90890-01500 This tool is used to loosen or tighten
the base valve.
Cap bolt ring wrench
YM-01501, 90890-01501 This tool is used to loosen or tighten
the damper assembly.
Fork seal driver
YM-A0948, 90890-01502 This tool is used when install the fork
oil seal.
Spoke nipple wrench
YM-01521, 90890-01521 This tool is used to tighten the
spoke.
Pocket tester
YU-3112-C, 90890-03112 Use this tool to inspect the coil resis-
tance, output voltage and amper-
age.
Tool name/Part number How to use Illustration

3-6
ENGINE
ENGINE
CHECKING THE COOLANT LEVEL
Do not remove the radiator cap
"1", drain bolt and hoses when the
engine and radiator are hot. Scald-
ing hot fluid and steam may be
blown out under pressure, which
could cause serious injury. When
the engine has cooled, place a
thick towel over the radiator cap,
slowly rotate the cap counter-
clockwise to the detent. This pro-
cedure allows any residual
pressure to escape. When the
hissing sound has stopped, press
down on the cap while turning
counterclockwise and remove it.
Hard water or salt water is harmful
to the engine parts. You may use
distilled water, if you can't get soft
water.
1. Place the machine on a level place, and hold it in an upright po-
sition.
2. Remove: • Radiator cap
3. Check: • Coolant level "a"Coolant level low →Add coolant.
1. Radiator
CHANGING THE COOLANT
Do not remove the radiator cap
when the engine is hot.
Take care so that coolant does not
splash on painted surfaces. If it
splashes, wash it away with water.
1. Place a container under the en- gine.
2. Remove: • Coolant drain bolt "1"
3. Remove: • Radiator capDrain the coolant completely.
4. Clean:
• Cooling systemThoroughly flush the cooling sys-
tem with clean tap water.
5. Install: • Copper washer
• Coolant drain bolt
6. Fill: • Radiator
•EngineTo specified level.
• Do not mix more than one type of
ethylene glycol antifreeze con-
taining corrosion inhibitors for
aluminum engine.
• Do not use water containing im- purities or oil.
Handling notes of coolant:
The coolant is harmful so it should be
handled with special care.
• When coolant splashes to your
eye.
Thoroughly wash your eye with
water and see your doctor.
• When coolant splashes to your clothes.
Quickly wash it away with water
and then with soap.
• When coolant is swallowed. Quickly make him vomit and take
him to a doctor.
7. Install:• Radiator cap
Start the engine and warm it up
for a several minutes.
8. Check:
• Coolant levelCoolant level low →Add coolant.
CHECKING THE RADIATOR CAP
1. Inspect: • Seal (radiator cap) "1"
• Valve and valve seat "2"Crack/damage →Replace.
Exist fur deposits "3" →Clean or
replace.
CHECKING THE RADIATOR CAP
OPENING PRESSURE
1. Attach: • Radiator cap tester "1" and adapt-er "2"
Apply water on the radiator cap seal.
Coolant drain bolt:
10 Nm (1.0 m•kg, 7.2
ft•lb)
Recommended coolant: High quality ethylene
glycol anti-freeze con-
taining anti -corrosion
for aluminum engine
Coolant "1" and water
(soft water) "2" mixing ra-
tio: 50%/50%
Coolant capacity: 1.00 L (0.88 Imp qt, 1.06
US qt)
Radiator cap tester:
YU-24460-01/90890-
01325
Radiator cap tester
adapter: YU-33984/90890-01352

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 levelThe 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 fore ign 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 strainerClogged →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 typeSAE10W-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): 1-3/4 turns out

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 tankRefer to "SEAT, FUEL TANK
AND SIDE COVERS" section in
the CHAPTER 4.
2. Remove:
• Spark plug
• Cylinder head coverRefer to "CAMSHAFTS" section
in the CHAPTER 4.
3. Remove: • Timing mark accessing screw "1"
• Crankshaft end accessing screw "2"
• O-ring
4. Check: • Valve clearanceOut 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)

3-17
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.