oil pressure YAMAHA WR 250F 2001 Owners Manual

SPEC

2 - 3
GENERAL SPECIFICATIONS
Tire:
Type With tube
Size (front) 80/100-21 51M (For USA, CDN and ZA)
90/90-21 54R (For EUROPE, AUS and NZ)
Size (rear) 100/100-18 59M (For USA, CDN and ZA)
120/90-18 65R (For EUROPE, AUS and NZ)
Tire pressure (front and rear) 100 kPa (1.0 kg/cm
2

, 15 psi)
Brake:
Front brake type Single disc brake
Operation Right hand operation
Rear brake type Single disc brake
Operation Right foot operation
Suspension:
Front suspension Telescopic fork
Rear suspension Swingarm (link type monocross suspension)
Shock absorber:
Front shock absorber Coil spring/oil damper
Rear shock absorber Coil spring/gas, oil damper
Wheel travel:
Front wheel travel 300 mm (11.8 in)
Rear wheel travel 315 mm (12.4 in)
Electrical:
Ignition system CDI magneto
Headlight type: Quartz bulb (halogen)
Bulb wattage
´
quantity:
Headlight 12 V 60/55 W
´
1
Taillight 12 V 21/5 W
´
1

SPEC

2 - 9
MAINTENANCE SPECIFICATIONS
Lubrication system:
Oil filter type Wire mesh type ----
Oil pump type Trochoid type ----
Tip clearance 0.12 mm or less
(0.0047 in or less)0.20 mm
(0.008 in)
Side clearance 0.09 ~ 0.17 mm
(0.0035 ~ 0.0067 in)0.24 mm
(0.009 in)
Housing and rotor clearance 0.03 ~ 0.10 mm
(0.0012 ~ 0.0039 in)0.17 mm
(0.0067 in)
Cooling:
Radiator core size
Width 117.8 mm (4.6 in) ----
Height 220 mm (8.7 in) ----
Thickness 32 mm (1.26 in) ----
Radiator cap opening pressure110 kPa (1.1 kg/cm
2

, 15.6 psi)----
Radiator capacity (total) 0.6 L (0.53 lmp qt, 0.63 US qt) ----
Water pump
Type Single-suction centrifugal pump ----Item Standard Limit

SPEC

2 - 10
MAINTENANCE SPECIFICATIONS
Part to be tightened Thread size Q’tyTightening torque
Nm m·kg ft·lb
Spark plug M10S
´
1.0 1 13 1.3 9.4
Camshaft cap M6
´
1.0 10 10 1.0 7.2
Cylinder head blind plug screw M12
´
1.0 1 37 3.7 27
Cylinder head (stud bolt) M6
´
1.0 2 7 0.7 5.1
(stud bolt) M8
´
1.25 1 15 1.5 11
(bolt) M9
´
1.25 4 38 3.8 27
(nut) M6
´
1.0 2 10 1.0 7.2
Cylinder head cover M6
´
1.0 2 10 1.0 7.2
Oil pressure check bolt M6
´
1.0 1 10 1.0 7.2
Cylinder M6
´
1.0 1 10 1.0 7.2
Balancer weight M6
´
1.0 2 10 1.0 7.2
Balancer shaft driven gear M14
´
1.0 1 50 5.0 36
Timing chain guide (intake side) M6
´
1.0 2 10 1.0 7.2
Decompression shaft M6
´
1.0 1 7 0.7 5.1
Decompression cable guide M6
´
1.0 1 10 1.0 7.2
Timing chain tensioner M6
´
1.0 2 10 1.0 7.2
Timing chain tensioner cap bolt M6
´
1.0 1 7 0.7 5.1
Impeller M8
´
1.25 1 14 1.4 10
Radiator hose clamp M6
´
1.0 8 2 0.2 1.4
Coolant drain bolt M6
´
1.0 1 10 1.0 7.2
Water pump housing M6
´
1.0 4 10 1.0 7.2
Radiator M6
´
1.0 6 10 1.0 7.2
Radiator guard M6
´
1.0 2 10 1.0 7.2
Radiator pipe M6
´
1.0 1 10 1.0 7.2
Oil pump cover M4
´
0.7 1 3 0.3 2.2
Oil pump M6
´
1.0 3 10 1.0 7.2
Oil filter element drain bolt M6
´
1.0 1 10 1.0 7.2
Oil filter element cover M6
´
1.0 2 10 1.0 7.2
Oil strainer M6
´
1.0 2 10 1.0 7.2
Oil delivery pipe 1 (M10) M10 ´ 1.25 1 20 2.0 14
(M8) M8 ´ 1.25 2 18 1.8 13
Oil delivery pipe 2 M6 ´ 1.0 1 10 1.0 7.2
Oil hose M6 ´ 1.0 3 10 1.0 7.2
Oil hose clamp — 2 2 0.2 1.4
Oil strainer and frame M18 ´ 1.5 1 90 9.0 65
Carburetor joint clamp M4 ´ 0.7 2 3 0.3 2.2
Air filter joint clamp M6 ´ 1.0 1 3 0.3 2.2
Throttle cable cover M5 ´ 0.8 1 4 0.4 2.9
Air filter joint M5 ´ 0.8 2 5 0.5 3.6
Air filter joint and air filter case M5 ´ 0.8 5 1 0.1 0.7
Air filter element M6 ´ 1.0 1 2 0.2 1.4
Air filter case cover M6 ´ 1.0 4 4 0.4 2.9
Exhaust pipe (nut) M8 ´ 1.25 1 13 1.3 9.4
(bolt) M8 ´ 1.25 1 24 2.4 17
Exhaust pipe protector M6 ´ 1.0 3 10 1.0 7.2

SPEC
2 - 12
MAINTENANCE SPECIFICATIONS
CHASSIS
Item Standard Limit
Steering system:
Steering bearing type Taper roller bearing ----
Front suspension: USA, CDN EUROPE AUS, NZ, ZA
Front fork travel 300 mm (11.8 in)¬¬
Fork spring free length 460 mm (18.1 in)¬¬
Spring rate, STD K = 4.31 N/mm
(0.44 kg/mm,
24.6 lb/in)K = 4.12 N/mm
(0.42 kg/mm,
23.5 lb/in)K = 4.02 N/mm
(0.41 kg/mm,
23 lb/in)
Optional spring/spacer Yes¬¬
Oil capacity 568 cm
3
(20.0 lmp oz,
19.2 US oz) 578 cm3
(20.3 lmp oz,
19.5 US oz) 568 cm3
(20.0 lmp oz,
19.2 US oz)
Oil level 140 mm (5.51 in) 130 mm (5.12 in) 140 mm (5.51 in)

(From top of outer tube with inner
tube and damper rod fully com-
pressed without spring.)80 ~ 150 mm
(3.15 ~ 5.91 in)¬¬
Oil grade Suspension oil
“01”¬¬
Inner tube outer diameter 46 mm (1.81 in)¬¬
Front fork top end 7 mm (0.28 in) 8 mm (0.31 in) 10.5 mm (0.41 in)
Rear suspension: USA, CDN EUROPE AUS, NZ, ZA
Shock absorber travel 132 mm (5.20 in)¬¬
Spring free length260 mm (10.24 in)¬¬
Fitting length240.5 mm (9.47 in)247 mm (9.72 in)243.5 mm (9.59 in)
240.5 ~ 258.5 mm
(9.47 ~ 10.18 in)¬¬
Spring rate, STD K = 47.0 N/mm
(4.80 kg/mm,
268.8 lb/in)¬¬
Optional spring Yes¬¬
Enclosed gas pressure
1,000 kPa
(10 kg/cm2, 142 psi)
¬¬
Swingarm:
Swingarm free play limit
End ---- 1.0 mm
(0.04 in)

3 - 3
INSP
ADJ

MAINTENANCE INTERVALS
* marked : For USAFRONT FORK OIL SEAL AND DUST
SEAL
Clean and lube
c

c
Lithium base grease
REAR SHOCK ABSORBER
Inspect and adjust
Lube
Retighten
c

c

c

c

c c Molybdenum disulfide
grease
CHAIN GUARD AND ROLLERS
Inspect
c c
SWINGARM
Inspect and retighten
c c
RELAY ARM, CONNECTING ROD
Inspect and lube
c c Molybdenum disulfide
grease
STEERING HEAD
Inspect free play and retighten
Clean and lube
Replace bearing
c c
c
c Lithium base grease
TIRE, WHEELS
Inspect air pressure, wheel run-out,
tire wear and spoke looseness
Retighten sprocket bolt
Inspect bearings
Replace bearings
Lubricate
c
c
c
c
c
c
c
Lithium base grease
THROTTLE, CONTROL CABLE
Check routing and connection
Lubricate
c
c
c
c Yamaha cable lube or
SAE 10W-30 motor oil ItemAfter
break-inEvery
race
Every
third race
or
500 km
(300 mi)Every
fifth race
or
1,000 km
(600 mi)
As re-
quiredRemarks

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.1-13
Engine oilCheck that the oil level is correct. Check the crankcase and
frame oil line for leakage.P.3-14 ~ 17
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 ~ 22

3 - 18
INSP
ADJ
OIL PRESSURE INSPECTION
1. Check:
lOil pressure
Checking steps:
lSlightly loosen the oil pressure check bolt
1.
lStart 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.
lCheck oil passages and oil pump for dam-
age or leakage.
lStart the engine after solving the prob-
lem(s) and recheck the oil pressure.
lTighten the oil pressure check bolt.
T R..
Oil pressure check bolt:
10 Nm (1.0 m • kg, 7.2 ft • lb)
PILOT SCREW ADJUSTMENT
1. Adjust:
lPilot screw 1
Adjustment steps:
NOTE:
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 num-
ber as the factory-set number of turns out.
lTurn in the pilot screw until it is lightly
seated.
lTurn out the pilot screw by the factory-set
number of turns.
Pilot screw:
1-3/4 turns out (example)
OIL PRESSURE INSPECTION/
PILOT SCREW ADJUSTMENT

3 - 33
INSP
ADJ
SPROCKETS INSPECTION/DRIVE CHAIN INSPECTION
SPROCKETS INSPECTION
1. Inspect:
lSprocket teeth a
Excessive wear ® Replace.
NOTE:
Replace the drive sprocket, rear wheel
sprocket and drive chain as a set.
DRIVE CHAIN INSPECTION
1. Remove:
lDrive chain 1
NOTE:
Remove the drive chain using a chain cutter
2.
2. Clean:
lDrive chain
Brush off as much dirt as possible.
Then clean the chain using the chain
cleaner.
CAUTION:
This machine has a drive chain with small
rubber O-rings 1 between the chain plates.
Steam cleaning, high-pressure washes,
certain solvent and kerosene can damage
these O-rings.
1
3. Measure:
lDrive chain length (10 links) a
Out of specification ® Replace.
Drive chain length (10 links):
: 150.1 mm (5.91 in)
4. Check:
lDrive chain stiffness a
Clean and oil the chain and hold as
illustrated.
Stiff ® Replace drive chain.

4 - 49
ENGCLUTCH
EC4A0000
CLUTCH
Extent of removal:1 Push rod 1, 2 and push lever shaft removal2 Push pod 1 disassembly
3 Friction plate and clutch plate removal4 Primary driven gear removal
Extent of removal Order Part name Q’ty Remarks
CLUTCH REMOVAL
Preparation for removal Drain the engine oil. Refer to “ENGINE OIL REPLACEMENT”
section in the CHAPTER 3.
Brake pedal Refer to “ENGINE REMOVAL” section.
Clutch cable Disconnect at engine side.
1 Clutch cover 1
2 Clutch spring 5
3 Pressure plate 1
4 Push rod 1 1
5 Circlip 1
6 Washer 1
7 Bearing 1
8 Ball 1
9Push rod 2
1
4
1
12
3

4 - 55
ENGCLUTCH
7. Install:
lPush rod 2 1
lBall 2
lPush rod 1 3
NOTE:
Apply the engine oil on the push rod 1, 2 and
ball.
8. Install:
lPressure plate 1
9. Install:
lClutch spring 1
lBolt (clutch spring) 2
NOTE:
Tighten the bolts in stage, using a crisscross
pattern.
T R..8 Nm (0.8 m · kg, 5.8 ft · lb)
10. Install:
lDowel pin 1
lGasket (clutch cover) 2
11. Install:
lClutch cover 1
lBolt (clutch cover)
NOTE:
Tighten the bolts in stage, using a crisscross
pattern.
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)