2002 YAMAHA YZ250F oil type

3 - 7
INSP
ADJ
RADIATOR CAP INSPECTION
CAUTION:
Do not mix more than one type of ethyl-
ene glycol antifreeze containing corro-
sion inhibitors for aluminum engine.
Do not use water containing impurities or
oil.
7. Install:
Radiator cap
Start the engine and warm it up for a
several minutes.
8. Check:
Coolant level
Coolant level low → Add coolant. Handling notes of coolant:
The coolant is harmful so it should be han-
dled with special care.
WARNING
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.
EC355000
RADIATOR CAP INSPECTION
1. Inspect:
Seal (radiator cap) 1
Valve and valve seat 2
Crack/damage → Replace.
Exist fur deposits 3 → Clean or
replace.

3 - 14
INSP
ADJ
3. Remove:
Oil tank cap 1
4. Inspect:
Oil level
Oil level should be between maximum
a and minimum b marks.
Oil level is low → Add oil to proper
level.
NOTE:
When inspecting the oil level, do not screw the
oil tank cap into the oil tank. Insert the gauge
lightly.
(For USA and CDN)
CAUTION:
Do not add any chemical additives.
Engine oil also lubricates the clutch and
additives could cause clutch slippage.
Do not allow foreign material to enter the
crankcase.
Recommended oil:
At 5 ˚C (40 ˚F) or higher Å
Yamalube 4 (20W-40) or SAE
20W-40 type SH motor oil (Non-
Friction modified)
At 15 ˚C (60 ˚F) or lower ı
Yamalube 4 (10W-30) or SAE
10W-30 type SH motor oil (Non-
Friction modified)
and/or
Yamalube 4-R (15W-50)
(Non-Friction modified)
ENGINE OIL LEVEL INSPECTION

5 - 25
CHASFRONT BRAKE AND REAR BRAKE
2. Install:
Brake hose holder 1
Screw (brake hose holder) 2
ACHTUNG:CAUTION:
After installing the brake hose holders,
make sure the brake hose does not contact
the spring (rear shock absorber). If it does,
correct its twist.
Brake fluid
1. Fill:
Brake fluid
Until the fluid level reaches “LOWER”
level line a.
WARNING
Use only the designated quality brake
fluid:
otherwise, the rubber seals may deterio-
rate, causing leakage and poor brake per-
formance.
Refill with the same type of brake fluid;
mixing fluids may result in a harmful chem-
ical reaction and lead to poor performance.
Be careful that water does not enter the
master cylinder when refilling. Water will
significantly lower the boiling point of the
fluid and may result in vapor lock.
ACHTUNG:CAUTION:
Brake fluid may erode painted surfaces or
plastic parts. Always clean up spilled fluid
immediately.
ÅFront
ıRear
Recommended brake fluid:
DOT #4
T R..1 Nm (0.1 m · kg, 0.7 ft · lb)
Å
ı

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CHASFRONT FORK
EC556000
HANDLING NOTE
NOTE:
The front fork requires careful attention. So it is
recommended that the front fork be main-
tained at the dealers.
ACHTUNG:CAUTION:
To prevent an accidental explosion of air,
the following instructions should be
observed:
The front fork with a built-in piston rod
has a very sophisticated internal con-
struction and is particularly sensitive to
foreign material.
Use enough care not to allow any foreign
material to come in when the oil is
replaced or when the front fork is disas-
sembled and reassembled.
Before removing the cap bolts or front
forks, be sure to extract the air from the
air chamber completely.
EC553000
REMOVAL POINTS
Front fork cap bolt
1. Remove:
Front fork cap bolt 1
From the outer tube.
NOTE:
Before removing the front fork from the
machine, loosen the front fork cap bolt.
2. Remove:
Front fork cap bolt 1
NOTE:
While compressing the fork spring, set the
thin type spanners 2 between the spacer 3
and spring guide 4.
Hold the locknut 5 and remove the front fork
cap bolt.

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CHAS
HANDLING NOTE
WARNING
This rear shock absorber is provided with a
separate type tank filled with high-pressure
nitrogen gas. To prevent the danger of
explosion, read and understand the follow-
ing information before handling the shock
absorber.
The manufacturer can not be held respon-
sible for property damage or personal
injury that may result from improper han-
dling.
1. Never tamper or attempt to disassem-
ble the cylinder or the tank.
2. Never throw the rear shock absorber
into an open flame or other high heat.
The rear shock absorber may explode
as a result of nitrogen gas expansion
and/or damage to the hose.
3. Be careful not to damage any part of
the gas tank. A damaged gas tank will
impair the damping performance or
cause a malfunction.
4. Take care not to scratch the contact
surface of the piston rod with the cylin-
der; or oil could leak out.
5. Never attempt to remove the plug at
the bottom of the nitrogen gas tank. It
is very dangerous to remove the plug.
6. When scrapping the rear shock
absorber, follow the instructions on
disposal.
NOTES ON DISPOSAL (YAMAHA DEALERS
ONLY)
Before disposing the rear shock absorber, be
sure to extract the nitrogen gas from valve 1.
Wear eye protection to prevent eye damage
from escaping gas and/or metal chips.
WARNING
To dispose of a damaged or worn-out rear
shock absorber, take the unit to your
Yamaha dealer for this disposal procedure.
REAR SHOCK ABSORBER

6 - 9
–+ELECTHROTTLE POSITION SENSOR SYSTEM
3. Inspect:
Throttle position sensor coil variable
resistance
Check that the resistance in increased
as the throttle grip is moved from the
full close position to the full open posi-
tion.
Out of specification → Replace.
Tester (+) lead → Yellow lead 1
Tester (–) lead → Black lead 2
Throttle position sen-
sor coil variable
resistanceTester
selector
position
Full closedFull opened
kΩ × 1 Zero ~ 3 kΩ
at 20 ˚C
(68 ˚F)4 ~ 6 kΩ at
20 ˚C
(68 ˚F)
THROTTLE POSITION SENSOR
REPLACEMENT AND ADJUSTMENT
1. Remove:
Throttle position sensor coupler
Screw (throttle position sensor) 1
Washer 2
Throttle position sensor 3
NOTE:
Loosen the screws (throttle position sensor)
using the T20 bit (tamper resistant fastener
type).
2. Replace:
Throttle position sensor
3. Install:
Throttle position sensor 1
Washer 2
Screw (throttle position sensor) 3
NOTE:
Align the slot a in the throttle position sen-
sor with the projection b on the carburetor.
Temporarily tighten the screws (throttle posi-
tion sensor).