coolant YAMAHA WR 250F 2002 User Guide

3 - 4
INSP
ADJ
PRE-OPERATION INSPECTION AND MAINTENANCE
EC320000
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 Routine Page
CoolantCheck that coolant is filled up to the radiator cap.
Check that the coolant level is correct in the coolant reservoir.
Check the cooling system for leakage.P.3-5 ~ 9
FuelCheck that a fresh gasoline is filled in the fuel tank. Check the
fuel line for leakage.P.1-14
Engine oilCheck that the oil level is correct. Check the crankcase and
frame oil line for leakage.P.3-14 ~ 18
Gear shifter and clutchCheck that gears can be shifted correctly in order and that the
clutch operates smoothly.P.3-9
Throttle grip/HousingCheck that the throttle grip operation and free play are correctly
adjusted. Lubricate the throttle grip and housing, if necessary.P.3-10 ~ 11
Brakes Check the play of front brake and effect of front and rear brake. P.3-26 ~ 32
Drive chainCheck drive chain slack and alignment. Check that the drive
chain is lubricated properly.P.3-33 ~ 35
WheelsCheck for excessive wear and tire pressure. Check for loose
spokes and have no excessive play.P.3-43 ~ 44
SteeringCheck that the handlebar can be turned smoothly and have no
excessive play.P.3-44 ~ 45
Front forks and rear shock
absorberCheck that they operate smoothly and there is no oil leakage. P.3-35 ~ 42
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 pipeCheck that the exhaust pipe is tightly mounted and has no
cracks.P.4-2
Rear wheel sprocket Check that the rear wheel sprocket tightening bolt is not loose. P.3-33
Lubrication Check for smooth operation. Lubricate if necessary. P.3-46
Bolts and nuts Check the chassis and engine for loose bolts and nuts. P.1-18
Lead connectorsCheck that the CDI magneto, CDI unit, and ignition coil are con-
nected tightly.P.1-6
SettingsIs the machine set suitably for the condition of the racing course
and weather or by taking into account the results of test runs
before racing? Are inspection and maintenance completely
done?P.7-1 ~ 23

3 - 5
INSP
ADJ
EC350000
ENGINE
EC351011
COOLANT LEVEL INSPECTION
WARNING
Do not remove the radiator cap 1, drain
bolt and hoses when the engine and radia-
tor are hot. Scalding 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 counterclockwise to the detent.
This procedure allows any residual pres-
sure to escape. When the hissing sound
has stopped, press down on the cap while
turning counterclockwise and remove it.
CAUTION:
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 position.
2. Inspect:
Coolant level
Coolant level should be between the
maximum a and minimum b marks.
Coolant level is below the “LOW” level
line → Add soft water (tap water) up to
the proper level.
3. Start the engine and let it warm up for
several minutes.
4. Turn off the engine and check the coolant
level again.
NOTE:
Before checking the coolant level, wait a few
minutes until the coolant settles.
LOWFULLCOOLANT
a
b
COOLANT REPLACEMENT
WARNING
Do not remove the radiator cap when the
engine is hot.
ENGINE/COOLANT LEVEL INSPECTION/
COOLANT REPLACEMENT

3 - 6
INSP
ADJ
COOLANT REPLACEMENT
CAUTION:
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 engine.
2. Remove:
Seat
Left side cover
Refer to ”SEAT FUEL TANK AND SIDE
COVERS” section in the CHAPTER 4.
3. Disconnect:
Coolant reservoir hose 1
Drain the coolant completely.
4. Connect:
Coolant reservoir hoseLOWFULLCOOLANT1
5. Remove:
Coolant drain bolt 1
6. Remove:
Radiator cap
Drain the coolant completely.
7. Clean:
Cooling system
Thoroughly flush the cooling system
with clean tap water.
8. Install:
Copper washer
Coolant drain bolt
9. Fill:
Radiator
Engine
To specified level.
Recommended coolant:
High quality ethylene glycol
anti-freeze containing
anti-corrosion for
aluminum engine
Coolant 1 and water
(soft water) 2 mixing ratio:
50%/50%
Coolant capacity:
1.3 L (1.14 Imp qt, 1.37 US qt)
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)

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.
10. Install:
Radiator cap
11. Fill:
Coolant reservoir
Midway a between maximum and min-
imum marks on the tank.
12. Install:
Coolant reservoir cap
13. Start the engine and let it warm up for
several minutes.
14. Turn off the engine and inspect the cool-
ant level.
Refer to “COOLANT LEVEL INSPEC-
TION” section.
NOTE:
Before checking the coolant level wait a few
minutes until the coolant settles.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.
LOWFULLCOOLANTa
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 - 8
INSP
ADJRADIATOR CAP OPENING PRESSURE INSPECTION/
COOLING SYSTEM INSPECTION
RADIATOR CAP OPENING PRESSURE
INSPECTION
1. Attach:
Radiator cap tester 1 and adapter 2
NOTE:
Apply water on the radiator cap seal.
3Radiator cap
2. Apply the specified pressure.
3. Inspect:
Pressure
Impossible to maintain the specified
pressure for 10 seconds → Replace.
Radiator cap tester:
YU-24460-01/90890-01325
Radiator cap tester adapter:
YU-33984/90890-01352
Radiator cap opening pressure:
110 kPa (1.1 kg/cm2, 15.6 psi)
COOLING SYSTEM INSPECTION
1. Inspect:
Coolant level
2. Attach:
Radiator cap tester 1 and adapter 2
3. Apply the specified pressure.
Radiator cap tester:
YU-24460-01/90890-01325
Radiator cap tester adapter:
YU-33984/90890-01352
Standard pressure:
180 kPa (1.8 kg/cm2, 25.6 psi)

3 - 9
INSP
ADJ
CLUTCH ADJUSTMENT
NOTE:
Do not apply pressure more than specified
pressure.
Radiator should be filled fully.
4. Inspect:
Pressure
Impossible to maintain the specified
pressure for 10 seconds → Repair.
Radiator 1
Radiator hose joint 2
Coolant leakage → Repair or replace.
Radiator hose 3
Swelling → Replace.
CLUTCH ADJUSTMENT
1. Check:
Clutch lever free play a
Out of specification → Adjust.
Clutch lever free play a:
8 ~ 13 mm (0.31 ~ 0.51 in)
2. Adjust:
Clutch lever free play
NOTE:
Make minute adjustment on the lever side
using the adjuster 2.
After adjustment, check proper operation of
clutch lever. Clutch lever free play adjustment steps:
Loosen the locknuts 1.
Adjust the free play by changing their
tightening position.
Tighten the locknuts.

3 - 19
INSP
ADJ
ENGINE IDLING SPEED ADJUSTMENT
1. Start the engine and thoroughly warm it
up.
2. Attach:
Inductive tachometer
To spark plug lead.
3. Adjust:
Engine idling speed
Adjustment steps:
Adjust the pilot screw.
Refer to “PILOT SCREW ADJUSTMENT”
section.
Turn the throttle stop screw 1 until the
engine runs at the lowest possible speed.
To increase idle speed → Turn the throt-
tle stop screw 1 in a.
To decrease idle speed → Turn the throt-
tle stop screw 1 out b.
Inductive tachometer:
YU-8036-B
Engine tachometer:
90890-03113
Engine idling speed:
1,800 ~ 2,100 r/min
VALVE CLEARANCE INSPECTION AND
ADJUSTMENT
NOTE:
The valve clearance should be adjusted
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 CHAP-
TER 4.
2. Drain:
Coolant
Refer to “COOLANT REPLACEMENT”
section.
ENGINE IDLING SPEED ADJUSTMENT/
VALVE CLEARANCE INSPECTION AND ADJUSTMENT

4 - 4
ENG

RADIATOR
EC450001
RADIATOR
Extent of removal:
1
Radiator removal
Extent of removal Order Part name Q’ty Remarks
RADIATOR REMOVAL
Preparation for removal Drain the coolant. Refer to “COOLANT REPLACEMENT”
section in the CHAPTER 3.
Seat, fuel tank and left Refer to “SEAT, FUEL TANK AND SIDE
COVERS” section.
Side cover
1 Radiator guard 2
2 Radiator hose clamp 8 Only loosening.
3 Radiator hose 1 1
4 Left radiator 1
5 Radiator hose 3 1
6 Coolant reservoir hose 1
7 Right radiator 1
8 Radiator hose 2 1
9 Radiator hose 4 1
10 Radiator pipe 1
11 Coolant reservoir breather hose 1
12 Coolant reservoir 1
1

4 - 6
ENGRADIATOR
3. Install:
Right radiator 1
Bolt (right radiator) 2
Radiator hose 3 3
Refer to “CABLE ROUTING DIA-
GRAM” section in the CHAPTER 2.
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
4. Install:
Left radiator 1
Bolt (left radiator) 2
Radiator hose 1 3
Refer to “CABLE ROUTING DIA-
GRAM” section in the CHAPTER 2.
5. Tighten:
Radiator hose clamp 4
6. Install:
Radiator guard 1
Bolt (radiator guard) 2
NOTE:
Fit the hook a on the inner side first into the
radiator.
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
T R..2 Nm (0.2 m · kg, 1.4 ft · lb)
T R..2 Nm (0.2 m · kg, 1.4 ft · lb)
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
7. Install:
Coolant reservoir 1
Clamp 2
Bolt [coolant reservoir (front)] 3
Bolt [coolant reservoir (rear)] 4
Coolant reservoir hose 5
Coolant reservoir breather hose 6
Refer to “CABLE ROUTING DIA-
GRAM” section in the CHAPTER 2.
8. Fill:
Radiator
Engine
Coolant reservoir
Refer to “COOLANT REPLACEMENT”
section in the CHAPTER 3.
LOWFULLCOOLANT
1
5
2
6
34
T R..7 Nm (0.7 m · kg, 5.1 ft · lb)
T R..11 Nm (1.1 m · kg, 8.0 ft · lb)

4 - 57
ENG

OIL FILTER ELEMENT, WATER PUMP AND RIGHT
CRANKCASE COVER
OIL FILTER ELEMENT, WATER PUMP AND RIGHT
CRANKCASE COVER
Extent of removal:
1
Oil filter element removal
2
Water pump removal
3
Right crankcase cover removal
Extent of removal Order Part name Q’ty Remarks
OIL FILTER ELEMENT, WATER
PUMP AND RIGHT CRANK-
CASE COVER REMOVAL
Preparation for removal Drain the engine oil. Refer to “ENGINE OIL REPLACEMENT”
section in the CHAPTER 3.
Drain the coolant. Refer to “COOLANT REPLACEMENT”
section in the CHAPTER 3.
Radiator hose 3 Disconnect at water pump side.
Exhaust pipe Refer to “EXHAUST PIPE AND
SILENCER” section.
Brake pedal Refer to “ENGINE REMOVAL” section.
Right engine guard
1 Oil filter element cover 1
2 Oil filter element 1
13