check oil YAMAHA YZ250F 2005 Notices Demploi (in French)

3 - 18
INSP
ADJ
ENGINE IDLING SPEED ADJUSTMENT
1. Start the engine and thoroughly warm it up.
2. Adjust:
Engine idling speed
Adjustment steps:
Adjust the pilot screw.
Refer to “PILOT SCREW ADJUSTMENT”
section.
Turn the throttle stop screw 1 until the
specified engine idling speed.
NOTE:
Using a digital engine tachometer for idle
speed adjustment, detect the engine idling
speed by bringing the sensing element c of
the engine tachometer close to the ignition
coil 2.
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.
Engine idling speed:
1,900 ~ 2,100 r/min
c2
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 CHAPTER 4.
2. Drain:
Coolant
Refer to “COOLANT REPLACEMENT”
section.
ENGINE IDLING SPEED ADJUSTMENT/
VALVE CLEARANCE INSPECTION AND ADJUSTMENT

3 - 32
INSP
ADJ
DRIVE CHAIN SLACK ADJUSTMENT
4. Check:
Drive chain stiffness a
Clean and oil the drive chain and hold as
illustrated.
Stiff → Replace drive chain.
5. Install:
Drive chain 1
Joint 2
Master link clip 3
CAUTION:
Be sure to install the master link clip to the
direction as shown.
aTurning direction
6. Lubricate:
Drive chain
Drive chain lubricant:
SAE 10W-30 motor oil or
suitable chain lubricants
DRIVE CHAIN SLACK ADJUSTMENT
1. Elevate the rear wheel by placing the suit-
able stand under the engine.
2. Check:
Drive 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 the drive chain
slack with the rear wheel in this “tight chain”
position.
Drive chain slack:
48 ~ 58 mm (1.9 ~ 2.3 in)

3 - 47
INSP
ADJ
IGNITION TIMING CHECK
IGNITION TIMING CHECK
1. Remove:
Timing mark accessing screw 1
2. Attach:
Timing light
Inductive tachometer
To the ignition coil lead (orange lead 1).
Timing light:
YM-33277-A/90890-03141
1
3. Adjust:
Engine idling speed
Refer to “ENGINE IDLING SPEED
ADJUSTMENT” section.
4. Check:
Ignition timing
Visually check the stationary pointer a is
within the firing range b on the rotor.
Incorrect firing range → Check rotor and
pickup assembly.
5. Install:
Timing mark accessing screw

4 - 26
ENGCAMSHAFTS
Decompression system
1. Check:
Decompression system
Timing chain tensioner
1. Check:
While pressing the tensioner rod lightly
with fingers, use a thin screwdriver 1
and wind the tensioner rod up fully clock-
wise.
When releasing the screwdriver by press-
ing lightly with fingers, make sure that the
tensioner rod will come out smoothly.
If not, replace the tensioner assembly.
ASSEMBLY AND INSTALLATION
Camshaft
1. Install:
Exhaust camshaft 1
Intake camshaft 2 Checking steps:
Check that the decompression mecha-
nism cam 1 moves smoothly.
Check that the decompression mecha-
nism cam lever pin 2 projects from the
camshaft.
Installation steps:
Turn the crankshaft counterclockwise with
a wrench.
NOTE:
Apply the molybdenum disulfide oil on the
camshafts.
Apply the engine oil on the decompression
system.
Squeezing the decompression lever
allows the crankshaft to be turned easily.
Align the T.D.C. mark a on the rotor with
the align mark b on the crankcase cover
when piston is at T.D.C. on compression
stroke.

4 - 68
ENGOIL PUMP
INSPECTION
Oil pump
1. Inspect:
Oil pump drive gear 1
Oil pump drive shaft 2
Rotor housing 3
Oil pump cover 4
Cracks/wear/damage → Replace.
1
32
4
2. Measure:
Tip clearance a
(between the inner rotor 1 and outer
rotor 2)
Side clearance b
(between the outer rotor 2 and rotor
housing 3)
Housing 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:
Unsmooth → Repeat steps #1 and #2 or
replace the defective parts.

4 - 94
ENGCRANKCASE AND CRANKSHAFT
2. Check:
Shifter operation
Transmission operation
Unsmooth operation → Repair.
3. Install:
Oil strainer 1
Bolt (oil strainer) 2
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
4. Apply:
Sealant
On the right crankcase 1.
NOTE:
Clean the contacting surface of left and right
crankcase before applying the sealant.
5. Install:
Dowel pin 1
O-ring 2
Right crankcase
To left crankcase.
NOTE:
Fit the right crankcase onto the left crank-
case. Tap lightly on the case with soft ham-
mer.
When 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 - 95
ENGCRANKCASE AND CRANKSHAFT
6. Tighten:
Hose guide 1
Clutch cable holder 2
Bolt (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:
Oil delivery pipe 2 1
O-ring 2
Bolt (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:
Timing chain 1
Timing chain guide (intake side) 2
Bolt (timing chain guide) 3
9. Remove:
Sealant
Forced out on the cylinder mating sur-
face.
10. Apply:
Engine oil
To the crank pin, bearing and oil delivery
hole.
11. Check:
Crankshaft and transmission operation.
Unsmooth operation → Repair.
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)

4 - 98
ENGTRANSMISSION, SHIFT CAM AND SHIFT FORK
EC4H4810
Shift fork, shift cam and segment
1. Inspect:
Shift fork 1
Wear/damage/scratches → Replace.
2. Inspect:
Shift cam 1
Segment 2
Wear/damage → Replace.
3. Check:
Shift 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:
5th pinion gear (24T) 1
3rd pinion gear (20T) 2
Collar 3
4th pinion gear (22T) 4
2nd pinion gear (16T) 5
To main axle 6.
NOTE:
Apply the molybdenum disulfide oil on the
inner and end surface of the idler gear and on
the inner surface of the sliding gear, then
install.

4 - 100
ENGTRANSMISSION, SHIFT CAM AND SHIFT FORK
5. Install:
Shift fork 1 (L) 1
Shift fork 2 (C) 2
Shift fork 3 (R) 3
Shift cam 4
To main axle and drive axle.
NOTE:
Apply the molybdenum disulfide oil on the
shift fork grooves.
Mesh the shift fork #1 (L) with the 4th wheel
gear 5 and #3 (R) with the 5th wheel gear 7
on the drive axle.
Mesh the shift fork #2 (C) with the 3rd pinion
gear 6 on the main axle.
6. Install:
Transmission assembly 1
To left crankcase 2.
NOTE:
Apply the engine oil on the bearings and guide
bars.
7. Check:
Shifter operation
Transmission operation
Unsmooth operation → Repair.

5 - 33
CHASFRONT FORK
4. After filling, pump the damper assembly 1
slowly up and down (about 200 mm (7.9 in)
stroke) several times to bleed the damper
assembly of air.
NOTE:
Be careful not to excessive full stroke. A stroke
of 200 mm (7.9 in) or more will cause air to
enter. In this case, repeat the steps 2 to 4.
5. Inspect:
Oil amount
While keeping the damper assembly fully
stretched, check that the oil is above the
step a on the damper assembly.
Below the step → Replenish fork oil
above the step.
6. Tighten:
Locknut 1
NOTE:
Fully finger tighten the locknut onto the
damper assembly.
7. Loosen:
Compression damping adjuster 1
NOTE:
Loosen the compression damping adjuster
finger tight.
Record the set position of the adjuster (the
amount of turning out the fully turned in posi-
tion).
8. Install:
Base valve 1
To damper assembly 2.
NOTE:
First bring the damper rod pressure to a maxi-
mum. Then install the base valve while releas-
ing the damper rod pressure.