2001 YAMAHA YZ250F check oil

3 - 17
INSP
ADJ
ENGINE OIL REPLACEMENT
8. Install:
lCopper washer 1
lOil strainer (frame) 2
lOil hose 3
lBolt (oil hose) 4
lOil hose clamp 5
lLower engine bracket
9. Install:
lCopper washer
lOil filter element drain bolt
lCrankcase oil drain bolt
lFrame oil drain bolt
10. Fill:
lEngine oil
11. Check:
lOil leakage
12. Install:
lOil tank cap
13. Check:
lEngine oil level
Oil quantity:
Total amount:
1.7 L (1.50 Imp qt, 1.80 US qt)
Periodic oil change:
1.5 L (1.32 Imp qt, 1.59 US qt)
With oil filter replacement:
1.6 L (1.41 Imp qt, 1.69 US qt)
T R..90 Nm (9.0 m · kg, 65 ft · lb)
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..10 Nm (1.0 m · kg, 7.2 ft · lb)
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
T R..20 Nm (2.0 m · kg, 14 ft · lb)
T R..23 Nm (2.3 m · kg, 17 ft · lb)

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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:
18 Nm (1.8 m • kg, 13 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

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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.
EC369002
DRIVE CHAIN INSPECTION
1. Remove:
lMaster link clip
lJoint 1
lDrive chain 2
2. Clean:
lDrive chain
Place it in kerosene, and brush off as
much dirt as possible. Then remove the
chain from the kerosene and dry the
chain.
3. Measure:
lDrive chain length (10 links) a
Out of specification ® Replace.
Drive chain length (10 links):
: 152.5 mm (6.00 in)
4. Check:
lDrive chain stiffness a
Clean and oil the chain and hold as
illustrated.
Stiff ® Replace drive chain.

3 - 33
INSP
ADJ
DRIVE CHAIN SLACK ADJUSTMENT
5. Install:
lDrive chain 1
lJoint 2
lMaster link clip 3
CAUTION:
Be sure to install the master link clip to the
direction as shown.
aTurning direction
6. Lubricate:
lDrive chain
Drive chain lubricant:
SAE 10W-30 motor oil or suit-
able chain lubricants
EC36A060
DRIVE CHAIN SLACK ADJUSTMENT
1. Elevate the rear wheel by placing the
suitable stand under the engine.
2. Check:
lDrive chain slack a
Above the seal guard installation bolt.
Out of specification ® Adjust.
NOTE:
Before checking and/or adjusting, rotate the
rear wheel through several revolutions and
check the slack several times to find the tight-
est point. Check and/or adjust chain slack with
rear wheel in this “tight chain” position.
Drive chain slack:
40 ~ 50 mm (1.6 ~ 2.0 in)

4 - 67
ENGOIL PUMP
INSPECTION
Oil pump
1. Inspect:
lOil pump drive gear 1
lOil pump drive shaft 2
lRotor housing 3
lOil pump cover 4
Cracks/wear/damage ® Replace.
1
32
4
2. Measure:
lTip clearance a
(between the inner rotor 1 and outer
rotor 2)
lSide clearance b
(between the outer rotor 2 and rotor
housing 3)
lHousing and rotor clearance c
(between the rotor housing 3 and
rotors 1 2)
Out of specification ® Replace the oil
pump assembly.
Tip clearance a:
0.12 mm or less
(0.0047 in or less)
: 0.20 mm (0.008 in)
Side clearance b:
0.09 ~ 0.17 mm (0.0035 ~ 0.0067 in)
: 0.24 mm (0.009 in)
Housing and rotor clearance c:
0.03 ~ 0.10 mm (0.0012 ~ 0.0039 in)
: 0.17 mm (0.0067 in)
3. Check:
lUnsmooth ® Repeat steps #1 and #2
or replace the defective parts.

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ENGCRANKCASE AND CRANKSHAFT
2. Check:
lShifter operation
lTransmission operation
Unsmooth operation ® Repair.
3. Install:
lOil strainer 1
lBolt (oil strainer) 2
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
4. Apply:
lSealant
On the right crankcase 1.
NOTE:
Clean the contacting surface of left and right
crankcase before applying the sealant.
5. Install:
lDowel pin 1
lO-ring 2
lRight crankcase
To left crankcase.
NOTE:
lFit the right crankcase onto the left crank-
case. Tap lightly on the case with soft ham-
mer.
lWhen installing the crankcase, the connect-
ing rod should be positioned at TDC (top
dead center).
Quick gasket®:
ACC-QUICK-GS-KT
YAMAHA Bond No. 1215:
90890-85505

4 - 94
ENGCRANKCASE AND CRANKSHAFT
6. Tighten:
lHose guide 1
lClutch cable holder 2
lBolt (crankcase) 3
NOTE:
Tighten the crankcase tightening bolts in
stage, using a crisscross pattern.
T R..12 Nm (1.2 m · kg, 8.7 ft · lb)
7. Install:
lOil delivery pipe 2 1
lO-ring 2
lBolt (oil delivery pipe 2) 3
NOTE:
Apply the lithium soap base grease on the O-
rings.
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
8. Install:
lTiming chain 1
lTiming chain guide (intake side) 2
lBolt (timing chain guide) 3
9. Remove:
lSealant
Forced out on the cylinder mating sur-
face.
10. Apply:
lEngine oil
To the crank pin, bearing and oil deliv-
ery hole.
11. Check:
lCrankshaft and transmission operation.
Unsmooth operation ® Repair.
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)

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ENGTRANSMISSION, SHIFT CAM AND SHIFT FORK
EC4H4810
Shift fork, shift cam and segment
1. Inspect:
lShift fork 1
Wear/damage/scratches ® Replace.
2. Inspect:
lShift cam 1
lSegment 2
Wear/damage ® Replace.
3. Check:
lShift fork movement
Unsmooth operation ® Replace shift
fork.
NOTE:
For a malfunctioning shift fork, replace not only
the shift fork itself but the two gears each adja-
cent to the shift fork.
EC4H5000
ASSEMBLY AND INSTALLATION
Transmission
1. Install:
l5th pinion gear (24T) 1
l3rd pinion gear (20T) 2
lCollar 3
l4th pinion gear (22T) 4
l2nd pinion gear (16T) 5
To main axle 6.
NOTE:
lApply the molybdenum disulfide oil on the
4th and 5th pinion gears inner circumference
and on the end surface.
lApply the molybdenum disulfide oil on the
2nd and 3rd pinion gears inner circumfer-
ence.