2010 YAMAHA YZ250F oil level

1-5
DESCRIPTION
DESCRIPTION
• The machine you have purchased may differ slightly from those shown in the following.
• Designs and specifications are subject to change without notice.
1. Clutch lever
2. Hot starter lever
3. Front brake lever
4. Throttle grip
5. Radiator cap
6. Fuel tank cap
7. Engine stop switch
8. Kickstarter crank
9. Fuel tank
10. Radiator
11. Coolant drain bolt
12. Rear brake pedal
13. Valve joint14. Fuel cock
15. Cold starter knob
16. Air filter
17. Drive chain
18. Shift pedal
19. Oil level check window
20. Front fork

1-13
STARTING AND BREAK-IN
STARTING AND BREAK-IN
FUEL
Always use the recommended fuel as
stated below. Also, be sure to use
new gasoline the day of a race.
Use only unleaded gasoline. The
use of leaded gasoline will cause
severe damage to the engine inter-
nal parts such as valves, piston
rings, and exhaust system, etc.
If knocking or pinging occurs, use a
different brand of gasoline or higher
octane grade.
• For refueling, be sure to stop the
engine and use enough care not
to spill any fuel. Also be sure to
avoid refueling close to a fire.
• Refuel after the engine, exhaust pipe, etc. have cooled off.
HANDLING NOTE
Never start or run the engine in a
closed area. The exhaust fumes
are poisonous; they can cause
loss of consciousness and death
in a very short time. Always oper-
ate the machine in a well-ventilated
area.
• The carburetor on this machine has a built-in accelerator pump.
Therefore, when starting the en-
gine, do not operate the throttle
or the spark plug will foul.
• Unlike a two-stroke engine, this engine cannot be kick started
when the throttle is open be-
cause the kickstarter may kick
back. Also, if the throttle is open
the air/fuel mixture may be too
lean for the engine to start.
• Before starting the machine, per- form the checks in the pre-opera-
tion check list.
AIR FILTER MAINTENANCE
According to "CLEANING THE AIR
FILTER ELEMENT" section in the
CHAPTER 3, apply the foam-air-filter
oil or its equivalent to the element.
(Excess oil in the element may ad-
versely affect engine starting.)
STARTING A COLD ENGINE
1. Inspect the coolant level.
2. Turn the fuel cock to "ON".
3. Shift the transmission into neutral.
4. Fully open the cold starter knob
"1".
5. Kick the kickstarter crank.
Do not open the throttle while kick-
ing the kickstarter crank. Other-
wise, the kickstarter crank may
kick back.
6. Return the cold starter knob to its original position and run the en-
gine at 3,000–5,000 r/min for 1 or
2 minutes.
Since this model is equipped with an
accelerator pump, if the engine is
raced (the throttle opened and
closed), the air/fuel mixture will be too
rich and the engine may stall. Also
unlike a two-stroke engine, this model
can idle.
Do not warm up the engine for ex-
tended periods of time.
STARTING A WARM ENGINE
Do not operate the cold starter knob
and throttle. Pull the hot starter lever
"1" and start the engine by kicking
the kickstarter crank forcefully with a
firm stroke. As soon as the engine
starts, release the hot starter lever to
close the air passage. Restarting an engine after a fall
Pull the hot starter lever and start the
engine. As soon as the engine starts,
release the hot starter lever to close
the air passage.
The engine fails to start
Pull the hot starter lever all the way
out and while holding the lever, kick
the kickstarter crank 10 to 20 times to
clear the engine. Then, restart the en-
gine. Refer to "Restarting an engine
after a fall".
Observe the following break-in
procedures during initial operation
to ensure optimum performance
and avoid engine damage.
Recommended fuel:
Premium unleaded
gasoline only with a re-
search octane number
of 95 or higher.
Thrott
le
grip
oper-
ation* Cold
start- er
knob Hot
start-
er le- ver
Star
ting
a
cold
en-
gine Air tem-
perature =
less than
5 °C (41
°F)
Open
3 or 4 times ON OFF
Air tem-
perature =
more than
5 °C (41
°F) None ON OFF
Air tem-
perature
(normal
tempera-
ture) = be-
tween 5
°C (41 °F)
and 25 °C
(77 °F) None
ON/
OFF OFF
Air tem-
perature =
more than
25 °C (77
°F) None OFF OFF
Starting an en-
gine after a long
period of time None ON OFF
Restarting a
warm engine None OFF ON
Restarting an
engine after a
fall None OFF ON
* Operate the throttle grip before kick
starting.

3-3
MAINTENANCE INTERVALS
COOLING SYSTEMCheck coolant level and leakage ●●
Check radiator cap operation ●
Replace coolant ●Every two years
Inspect hoses ●
OUTSIDE NUTS AND BOLTS Retighten ●● Refer to "STARTING AND BREAK-
IN" section in the CHAPTER 1.
AIR FILTER Clean and lubricate ●● Use foam air-filter oil or equivalent oil.
Replace ●
OIL FILTER Replace ●●
OIL STRAINER Clean ●
ENGINE GUARD Replace ●Breakage
FRAME Clean and inspect ●●
FUEL TANK, COCK Clean and inspect ●●
BRAKES Adjust lever position and pedal
height ●●
Lubricate pivot point ●●
Check brake disc surface ●●
Check fluid level and leakage ●●
Retighten brake disc bolts, cali-
per bolts, master cylinder bolts
and union bolts ●●
Replace pads ●
Replace brake fluid ●Every one year
FRONT FORKS Inspect and adjust ●●
Replace oil ●● Suspension oil "S1"
Replace oil seal ●
FRONT FORK OIL SEAL AND
DUST SEAL Clean and lube ●● Lithium base grease
PROTECTOR GUIDE Replace ●
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

3-6
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

4-35
OIL FILTER ELEMENT AND WATER PUMP
REMOVING THE IMPELLER
SHAFT
1. Remove:• Impeller "1"
• Washer "2"
• Impeller shaft "3"
Hold the impeller shaft on its width
across the flats "a" with spanners,
etc. and remove the impeller.
REMOVING THE OIL SEAL
It is not necessary to disassemble the
water pump, unless there is an abnor-
mality such as excessive change in
coolant level, discoloration of coolant,
or milky transmission oil.
1. Remove:• Bearing "1"
2. Remove: • Oil seal "1" CHECKING THE OIL DELIVERY
PIPE
1. Inspect:
• Oil delivery pipe "1"
Bend/damage →Replace.
Clogged →Blow.
CHECKING THE IMPELLER SHAFT
1. Inspect: • Impeller shaft "1"Bend/wear/damage →Replace.
Fur deposits →Clean.
CHECKING THE IMPELLER SHAFT
GEAR
1. Inspect: • Gear teeth "a"Wear/damage →Replace.
CHECKING THE BEARING
1. Inspect: •BearingRotate inner race with a finger.
Rough spot/seizure →Replace. CHECKING THE OIL SEAL
1. Inspect:
• Oil seal "1"Wear/damage →Replace.
INSTALLING THE OIL SEAL
1. Install: • Oil seal "1"
• Apply the lithium soap base grease on the oil seal lip.
• Install the oil seal with its manufac- ture's marks or numbers facing the
right crankcase cover "2".
2. Install:• Bearing "1"
Install the bearing by pressing its out-
er race parallel.