2001 YAMAHA YZ250F engine

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INSP
ADJ
3. Remove:
lOil tank cap 1
4. Inspect:
lOil 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:
lDo not add any chemical additives.
Engine oil also lubricates the clutch and
additives could cause clutch slippage.
lDo not allow foreign material to enter the
crankcase.
Recommended oil:
At 5 ˚C (40 ˚F) or higher
Yamalube 4 (20W-40) or SAE
20W-40 type SH motor oil (Non-
Friction modified)
At 15 ˚C (60 ˚F) or lower õ
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

3 - 15
INSP
ADJ
ENGINE OIL REPLACEMENT
(Except for USA and CDN)
CAUTION:
lDo not add any chemical additives or use
oils with a grade of CD a or higher.
lDo not use oils labeled “ENERGY CON-
SERVING II” b or higher. Engine oil also
lubricates the clutch and additives could
cause clutch slippage.
lDo not allow foreign materials to enter the
crankcase.
5. Install:
lOil tank cap
6. Start the engine and let it warm up for
several minutes.
7. Turn off the engine and inspect the oil
level once again.
NOTE:
Wait a few minutes until the oil settles before
inspecting the oil level.
Recommended oil:
Refer to the following chart for
selection of oils which are suited
to the atmospheric temperatures.
Recommended engine oil classi-
fication:
API STANDARD:
API “SH” or higher grade
(Designed primarily for motor-
cycles)
-20
-4-10
140
3010
5020
6830
8640 50
104
122¡CTemp.
¡F
10W-30
10W-40
20W-40
20W-50
15W-40
a
b
ENGINE OIL REPLACEMENT
1. Start the engine and warm it up for sev-
eral 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 position by placing the
suitable stand under the engine.
3. Place a suitable container under the
engine.

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INSP
ADJ
ENGINE OIL REPLACEMENT
4. Remove:
lOil tank cap 1
lFrame oil drain bolt 2
lCrankcase oil drain bolt 3
lOil filter element drain bolt 4
Drain the crankcase and oil tank
(frame) of its oil.
5. Remove:
lLower engine bracket
lOil hose clamp 1
lBolt (oil hose) 2
lOil hose 3
lOil strainer (frame) 4
6. Inspect:
lOil strainer (frame)
lClogged ® Blow.
7. If the oil filter is to be replaced during this
oil change, remove the following parts
and reinstall them.
Replacement steps:
lRemove the oil filter element cover 1 and
oil filter element 2.
lCheck the O-rings 3, if cracked or dam-
aged, replace them with a new one.
lInstall the oil filter element and oil filter ele-
ment cover.
T R..
Oil filter element cover:
10 Nm (1.0 m • kg, 7.2 ft • lb)

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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
ENGINE IDLING SPEED ADJUSTMENT
1. Start the engine and thoroughly warm it
up.
2. Attach:
lInductive tachometer
To spark plug lead.
3. Adjust:
lEngine idling speed
Adjustment steps:
lAdjust the pilot screw.
Refer to “PILOT SCREW ADJUSTMENT”
section.
lTurn the throttle stop screw 1 until the
engine runs at the lowest possible speed.
To increase idle speed ®
Turn the throttle stop screw 1 in a.
To decrease idle speed ®
Turn the throttle stop screw 1 out b.
Inductive tachometer:
YU-08036-B
Engine tachometer:
90890-03113
Engine idling speed:
1,700 ~ 1,900 r/min
VALVE CLEARANCE INSPECTION AND
ADJUSTMENT
NOTE:
lThe valve clearance should be adjusted
when the engine is cool to the touch.
lThe piston must be at Top Dead Center
(T.D.C.) on compression stroke to check or
adjust the valve clearance.
1. Remove:
lSeat
lFuel tank
Refer to “SEAT, FUEL TANK AND
SIDE COVERS” section in the CHAP-
TER 4.
2. Drain:
lCoolant
Refer to “COOLANT REPLACEMENT”
section.
ENGINE IDLING SPEED ADJUSTMENT/
VALVE CLEARANCE INSPECTION AND ADJUSTMENT

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INSP
ADJ
VALVE CLEARANCE INSPECTION AND ADJUSTMENT
3. Remove:
lRight radiator
Refer to “RADIATOR” section in the
CHAPTER 4.
lCarburetor
Refer to “CARBURETOR” section in
the CHAPTER 4.
lSpark plug
lUpper engine bracket
lCylinder head cover
Refer to “CAMSHAFTS” section in the
CHAPTER 4.
4. Remove:
lTiming mark accessing screw 1
lCrankshaft end accessing screw 2
lO-ring
5. Check:
lValve clearance
Out of specification ® Adjust.
Valve clearance (cold):
Intake valve:
0.10 ~ 0.15 mm (0.0039 ~ 0.0059 in)
Exhaust valve:
0.17 ~ 0.22 mm (0.0067 ~ 0.0087 in)

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INSP
ADJ
VALVE CLEARANCE INSPECTION AND ADJUSTMENT
lLocate the rounded-off value and the
measured valve clearance in the chart
“PAD SELECTION TABLE”. The field
where these two coordinates intersect
shows the new pad number to use.
NOTE:
Use the new pad number only as a guide
when verifying the valve clearance adjust-
ment.
lInstall the new pads 7 and the valve lift-
ers 8.
NOTE:
lApply the engine oil on the valve lifters.
lApply the molybdenum disulfied oil on the
valve stem ends.
lValve lifter must turn smoothly when
rotated with a finger.
lBe careful to reinstall valve lifters and
pads in their original place.
lInstall the decompression shaft 9, copper
washer 0, bolt (decompression shaft) A,
guide B, bolt (guide) C and decompres-
sion cable D.
NOTE:
Apply the engine oil on the decompression
shaft.
T R..
Bolt (decompression shaft):
7 Nm (0.7 m • kg, 5.1 ft • lb)
Bolt (guide):
10 Nm (1.0 m • kg, 7.2 ft • lb)
lInstall the camshafts (exhaust and intake).
Refer to “CAMSHAFTS” section in the
CHAPTER 4.