oil YAMAHA YZ250F 2006 Manuale duso (in Italian)

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INSP
ADJ
ENGINE OIL REPLACEMENT
7. If the oil filter is to be replaced during this
oil change, remove the following parts and
reinstall them.
8. Install:
O-ring 1
Oil strainer 2
Oil hose
Bolt (oil hose)
Oil hose clamp
9. Install:
Copper washer
Oil filter element drain bolt
Crankcase oil drain bolt
Oil tank drain bolt
Lower engine guard
10. Fill:
Engine oil
11. Check:
Oil leakage
12. Install:
Oil filler cap
Washer (oil tank)
Bolt (oil tank)
13. Check:
Engine oil level Replacement steps:
Remove the oil filter element cover 1 and
oil filter element 2.
Check the O-rings 3, if cracked or dam-
aged, replace them with a new one.
Install 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)
Oil quantity:
Periodic oil change:
1.15 L (1.01 Imp qt, 1.22 US qt)
With oil filter replacement:
1.25 L (1.10 Imp qt, 1.32 US qt)
Total amount:
1.40 L (1.23 Imp qt, 1.48 US qt)
1
2
T R..9 Nm (0.9 m · kg, 6.5 ft · lb)
T R..8 Nm (0.8 m · kg, 5.8 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..20 Nm (2.0 m · kg, 14 ft · lb)
T R..18 Nm (1.8 m · kg, 13 ft · lb)
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
T R..7 Nm (0.7 m · kg, 5.1 ft · lb)

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INSP
ADJ
OIL PRESSURE INSPECTION
1. Check:
Oil pressure
Checking steps:
Slightly loosen the oil pressure check bolt
1.
Start 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.
Check oil passages and oil pump for dam-
age or leakage.
Start the engine after solving the prob-
lem(s) and recheck the oil pressure.
Tighten 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:
Pilot screw 1
* Except for USA and CDNAdjustment 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.
Turn in the pilot screw until it is lightly
seated.
Turn out the pilot screw by the factory-set
number of turns.
Pilot screw (example):
2-1/2 turns out
* 2-1/4 turns out
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. 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.
ENGINE IDLING SPEED ADJUSTMENT/
VALVE CLEARANCE INSPECTION AND ADJUSTMENT

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INSP
ADJ
VALVE CLEARANCE INSPECTION AND ADJUSTMENT
NOTE:
The thickness a of each pad is indicated in
hundreths of millimeters on the pad upper
surface.
Round off the last digit of the installed pad
number to the nearest increment.
Last digit of pad
numberRounded value
0, 1 or 2 0
4, 5 or 6 5
8 or 9 10
EXAMPLE:
Installed pad number = 148
Rounded off value = 150
NOTE:
Pads can only be selected in 0.05 mm incre-
ments.
Locate the rounded-off value and the mea-
sured 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.
Install the new pads 3 and the valve lift-
ers 4.
NOTE:
Apply the engine oil on the valve lifters.
Apply the molybdenum disulfide oil on the
valve stem ends.
Valve lifter must turn smoothly when
rotated with a finger.
Be careful to reinstall valve lifters and
pads in their original place.
Install the camshafts (exhaust and intake).
Refer to “CAMSHAFTS” section in the
CHAPTER 4.

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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)

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INSP
ADJ
FRONT FORK INSPECTION
3. Adjust:
Drive chain slack
Drive chain slack adjustment steps:
Loosen the axle nut 1 and locknuts 2.
Adjust the drive chain slack by turning the
adjusters 3.
To tighten
→ Turn the adjuster
3 coun-
terclockwise.
To loosen
→ Turn the adjuster
3 clock-
wise and push wheel forward.
Turn each adjuster exactly the same
amount to maintain correct axle alignment.
(There are marks a on each side of the
drive chain puller alignment.)
NOTE:
Turn the adjuster so that the drive chain is in
line with the sprocket, as viewed from the
rear.
CAUTION:
Too small drive chain slack will overload
the engine and other vital parts; keep the
slack within the specified limits.
Tighten the axle nut while pushing down
the drive chain.
T R..
Axle nut:
125 Nm (12.5 m  kg, 90 ft  lb)
Tighten the locknuts.
T R..
Locknut:
16 Nm (1.6 m  kg, 11 ft  lb)
EC36C000
FRONT FORK INSPECTION
1. Inspect:
Front fork smooth action
Operate the front brake and stroke the
front fork.
Unsmooth action/oil leakage → Repair or
replace.

3 - 33
INSP
ADJFRONT FORK OIL SEAL AND DUST SEAL CLEANING/
FRONT FORK INTERNAL PRESSURE RELIEVING/
FRONT FORK REBOUND DAMPING FORCE ADJUSTMENT
EC36D001
FRONT FORK OIL SEAL AND DUST SEAL
CLEANING
1. Remove:
Protector
Dust seal 1
NOTE:
Use a thin screw driver, and be careful not to
damage the inner fork tube and dust seal.
2. Clean:
Dust seal a
Oil seal b
NOTE:
Clean the dust seal and oil seal after every
run.
Apply the lithium soap base grease on the
inner tube.
FRONT FORK INTERNAL PRESSURE
RELIEVING
NOTE:
If the front fork initial movement feels stiff dur-
ing a run, relieve the front fork internal pres-
sure.
1. Elevate the front wheel by placing a suit-
able stand under the engine.
2. Remove the air bleed screw 1 and release
the internal pressure from the front fork.
3. Install:
Air bleed screw
EC36H002
FRONT FORK REBOUND DAMPING FORCE
ADJUSTMENT
1. Adjust:
Rebound damping force
By turning the adjuster 1.
Stiffer a → Increase the rebound damp-
ing force. (Turn the adjuster 1 in.)
Softer b → Decrease the rebound damp-
ing force. (Turn the adjuster 1 out.)
T R..1 Nm (0.1 m · kg, 0.7 ft · lb)

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INSP
ADJ
REAR SHOCK ABSORBER INSPECTION
Extent of adjustment
Maximum Minimum
Fully turned in
position20 clicks out
(from maximum
position)
STANDARD POSITION:
This is the position which is back by the spe-
cific number of clicks from the fully turned-in
position.
* For EUROPE
CAUTION:
Do not force the adjuster past the minimum
or maximum extent of adjustment. The
adjuster may be damaged.
WARNING
Always adjust each front fork to the same
setting. Uneven adjustment can cause poor
handling and loss of stability.
Standard position:
12 clicks out
* 10 clicks out
EC36K000
REAR SHOCK ABSORBER INSPECTION
1. Inspect:
Swingarm smooth action
Abnormal noise/unsmooth action →
Grease the pivoting points or repair the
pivoting points.
Damage/oil leakage → Replace.

INSP
ADJ
REIFENLUFTDRUCK
KONTROLLIEREN
1. Messen:
Reifenluftdruck
Nicht nach Vorgabe → Einstel-
len.
HINWEIS:
Den Reifenluftdruck bei kaltem
Reifen kontrollieren.
Bei zu niedrigem Reifenluftdruck
besteht die Gefahr, dass der Rei-
fen auf der Felge rutscht.
Ein schräg stehender Ventilschaft
deutet darauf hin, dass der Reifen
sich verschoben hat.
Falls der Ventilschaft schräg steht,
sitzt der Reifen falsch auf. In die-
sem Fall die Reifenlage korrigieren.
Standard-Reifenluft-
druck:
100 kPa
(1,0 kgf/cm
2, 15 psi)
SPEICHEN KONTROLLIEREN UND
SPANNEN
1. Kontrollieren:
Speichen 1
Verbogen/beschädigt →
Erneuern.
Speiche lose → Spannen.
2. Festziehen:
Speichen
HINWEIS:
Die Speichen müssen vor und nach
dem Einfahren gespannt und nach
jeder Fahrt kontrolliert werden.
T R..3 Nm (0,3 m · kg, 2,2 ft · lb)
RÄDER KONTROLLIEREN
1. Kontrollieren:
Felgenschlag
Das Rad anheben und dre-
hen.
Anormaler Schlag → Erneu-
ern. CONTROLE DE LA PRESSION DES
PNEUS
1. Mesurer:
Pression des pneus
Hors spécifications → Régler.
N.B.:
Contrôler les pneus à froid.
Le pneu risque de se déjanter si le
gonflage est insuffisant.
Une tige de valve de pneu inclinée
indique que le pneu est mal assis.
Une tige de valve de pneu inclinée
indique que le pneu est mal assis. Cor-
riger la position du pneu.
Pression des pneus stan-
dard:
100 kPa
(1,0 kgf/cm
2, 15 psi)
CONTROLE ET SERRAGE DES
RAYONS
1. Contrôler:
Rayons 1
Déformation/endommagement →
Remplacer.
Rayon desserré → Resserrer.
2. Serrer:
Rayons
N.B.:
Veiller à resserrer ces rayons avant et
après le rodage. Après tout entraînement
ou toute course, contrôler la tension des
rayons.
T R..3 Nm (0,3 m · kg, 2,2 ft · lb)
CONTROLE DES ROUES
1. Contrôler:
Voile de roue
Surélever la roue et la faire tour-
ner.
Voile excessif → Remplacer.CONTROLLO PRESSIONE DEI
PNEUMATICI
1. Misurare:
Pressione dei pneumatici
Non conforme alle specifiche →
Regolare.
NOTA:
Controllare il pneumatico quando è
freddo.
Se gli elementi di arresto del tallone
sono lenti, il pneumatico scivola via
dalla sua posizione sul cerchio quando
la pressione è bassa.
La valvola del pneumatico inclinata
indica che il pneumatico scivola via
dalla sua posizione sul cerchio.
Se si nota che la valvola del pneuma-
tico è inclinata, il pneumatico è fuori
posizione. Correggere la posizione del
pneumatico.
Pressione standard dei
pneumatici:
100 kPa
(1,0 kgf/cm
2, 15 psi)
CONTROLLO E SERRAGGIO DEI
RAGGI
1. Controllare:
Raggi 1
Deformazioni/danni → Sostituire.
Raggio lento → Serrare.
2. Serrare:
Raggi
NOTA:
Assicurarsi di serrare i raggi prima e
dopo il rodaggio. Dopo l’utilizzo o dopo
una competizione, controllare che i raggi
non siano lenti.
T R..3 Nm (0,3 m · kg, 2,2 ft · lb)
CONTROLLO DELLE RUOTE
1. Controllare:
Scentratura ruota
Sollevare la ruota e farla ruotare.
Scentratura anomala → Sostitu-
ire.
CONTROLE DE LA PRESSION DES PNEUS/
CONTROLE ET SERRAGE DES RAYONS/CONTROLE DES ROUES
REIFENLUFTDRUCK KONTROLLIEREN/
SPEICHEN KONTROLLIEREN UND SPANNEN/RÄDER KONTROLLIEREN
CONTROLLO PRESSIONE DEI PNEUMATICI/
CONTROLLO E SERRAGGIO DEI RAGGI/CONTROLLO DELLE RUOTE
3 - 40

3 - 44
INSP
ADJ
LUBRICATION
LUBRICATION
To ensure smooth operation of all compo-
nents, lubricate your machine during setup,
after break-in, and after every race.
1All control cable
2Clutch lever pivot
3Shift pedal pivot
4Footrest pivot
5Throttle-to-handlebar contact
6Drive chain
7Tube guide cable winding portion
8Throttle cable end
9Clutch cable end
0Hot starter cable end
ÈUse Yamaha cable lube or equivalent on these
areas.
ÉUse SAE 10W-30 motor oil or suitable chain
lubricants.
ÊLubricate the following areas with high quality,
lightweight lithium-soap base grease.
CAUTION:
Wipe off any excess grease, and avoid get-
ting grease on the brake discs.
AAA
AAB
CC