oil YAMAHA YZ250F 2003 Manuale duso (in Italian)

2 - 19
SPECCABLE ROUTING DIAGRAM
ÒMake sure that the throttle
position sensor lead coupler
does not go out side the chas-
sis.
˜Fasten the throttle position
sensor lead.
ˆFasten the neutral switch lead
on the oil hose with a plastic
locking tie and cut off the tie
end.
ØFasten the neutral switch lead.
∏Fasten the neutral switch lead
and CDI magneto lead.
ŒPass the neutral switch lead,
CDI magneto lead and radiator
breather hose between the
radiator and frame.ÂPass the carburetor breather
hoses and overflow hose so
that all there hoses do not con-
tact the rear shock absorber.

2 - 20
SPEC
1CDI unit
2Hot starter cable
3Throttle cable (return)
4Throttle cable (pull)
5Cable guide
6Ignition coil
7Radiator hose 2
8Radiator breather hose
9Radiator hose 4
0CDI unit bracket
ACDI unit bandÅPass the hot starter cable and
throttle cables through the
cable guides.
ıPass the hot starter cable and
throttle cables between the
radiator and frame, then under
the radiator mounting boss.
ÇPass the throttle cables on the
outside of the ignition coil.
ÎPass the radiator breather
hose in front of the radiator
hose 2, on the left of the chas-
sis, and then between the
frame and radiator hose 4.
‰Insert the CDI unit band over
the CDI unit bracket as far as
possible.ÏFirst install the CDI unit and
CDI unit band to the CDI unit
bracket, then the CDI unit
bracket to the frame.
7
8
91
A0
2
3
4 1 Î
ω
Å
ı
Ç B
A
A
B
5
6
CABLE ROUTING DIAGRAM

3 - 1
INSP
ADJ
MAINTENANCE INTERVALS
EC300000
REGULAR INSPECTION AND ADJUSTMENTS
MAINTENANCE INTERVALS
The following schedule is intended as a general guide to maintenance and lubrication. Bear in mind
that such factors as weather, terrain, geographical location, and individual usage will alter the
required maintenance and lubrication intervals. If you are a doubt as to what intervals to follow in
maintaining and lubricating your machine, consult your Yamaha dealer.
ItemAfter
break-inEvery
race
Every
third
(or
500 km)Every
fifth
(or
1,000 km)As re-
quiredRemarks
ENGINE OIL
Replace
Inspect
●
●●

●
OIL FILTER ELEMENT, OIL STRAINER
Clean
●
VALVES
Check the valve clearances
Inspect
Replace
● ●
●
● The engine must be cold.
Check the valve seats
and valve stems for wear.
VALVE SPRINGS
Inspect
Replace
●
● Check the free length and
the tilt.
VALVE LIFTERS
Inspect
Replace
●
● Check for scratches and
wear.
CAMSHAFTS
Inspect
Replace
●
● Inspect the camshaft sur-
face.
Inspect the decompres-
sion system.
TIMING CHAIN SPROCKETS, TIMING
CHAIN
Inspect
Replace
●
● Check for wear on the
teeth and for damage.
PISTON
Inspect
Clean
Replace
● ●
●
● Inspect crack
Inspect carbon deposits
and eliminate them.
PISTON RING
Inspect
Replace
●
● ● Check ring end gap
PISTON PIN
Inspect
Replace
●
●
CYLINDER HEAD
Inspect and clean
● Inspect carbon deposits
and eliminate them.
Change gasket
CYLINDER
Inspect and clean
Replace
●
● Inspect score marks
Inspect wear
CLUTCH
Inspect and adjust
Replace
● ●
● Inspect housing, friction
plate, clutch plate and
spring
TRANSMISSION
Inspect
Replace bearing
●
●

3 - 2
INSP
ADJ
MAINTENANCE INTERVALS
SHIFT FORK, SHIFT CAM, GUIDE BAR
Inspect
● Inspect wear
ROTOR NUT
Retighten
● ●
EXHAUST PIPE, SILENCER, PRO-
TECTOR
Inspect and retighten
Clean
Replace
● ●
●
● * Whichever comes first
CRANK
Inspect and clean
● ●
CARBURETOR
Inspect, adjust and clean
● ● When using a high-pres-
sure washer, make sure
that water does not enter
the accelerator pump.
SPARK PLUG
Inspect and clean
Replace
● ●
●
DRIVE CHAIN
Lubricate, slack, alignment
Replace
● ●
● Use chain lube
Chain slack: 40 ~ 50 mm
(1.6 ~ 2.0 in)
COOLING SYSTEM
Check coolant level and leakage
Check radiator cap operation
Replace coolant
Inspect hoses
● ●
●
●
● Every two years
OUTSIDE NUTS AND BOLTS
Retighten
● ● Refer to “STARTING
AND BREAK-IN” section
in the CHAPTER 1.
AIR FILTER
Clean and lubricate
Replace
● ●
● Use foam air-filter oil or
equivalent oil
OIL FILTER
Replace
●●
OIL STRAINER (frame)
Clean
●
FRAME
Clean and inspect
● ●
FUEL TANK, COCK
Clean and inspect
● ●
BRAKES
Adjust lever position and pedal height
Lubricate pivot point
Check brake disc surface
Check fluid level and leakage
Retighten brake disc bolts, caliper
bolts, master cylinder bolts and union
bolts
Replace pads
Replace brake fluid
●
●
●
●
●
●
●
●
●
●
●
● Every one year ItemAfter
break-inEvery
race
Every
third
(or
500 km)Every
fifth
(or
1,000 km)As re-
quiredRemarks
3

3 - 3
INSP
ADJ
MAINTENANCE INTERVALS
FRONT FORKS
Inspect and adjust
Replace oil
Replace oil seal
●
●
●
●
● Suspension oil “01”
FRONT FORK OIL SEAL AND DUST
SEAL
Clean and lube
● ● Lithium base grease
REAR SHOCK ABSORBER
Inspect and adjust
Lube
Retighten
●
●
●
●
●
(After
rain ride)
●Molybdenum disulfide
grease
DRIVE CHAIN GUIDE AND ROLLERS
Inspect
● ●
SWINGARM
Inspect, lube and retighten
● ● Molybdenum disulfide
grease
RELAY ARM, CONNECTING ROD
Inspect, lube and retighten
● ● Molybdenum disulfide
grease
STEERING HEAD
Inspect free play and retighten
Clean and lube
Replace bearing
● ●
●
● Lithium base grease
TIRE, WHEELS
Inspect air pressure, wheel run-out,
tire wear and spoke looseness
Retighten sprocket bolt
Inspect bearings
Replace bearings
Lubricate
●
●
●
●
●
●
●
Lithium base grease
THROTTLE, CONTROL CABLE
Check routing and connection
Lubricate
Inspect and clean (throttle cable)
●
●
● ●

●
● Yamaha cable lube or
SAE 10W-30 motor oil
Inspect dirt and wear on
the throttle cable on the
carburetor side.
HOT STARTER, CLUTCH LEVER
Inspect free play
●
ItemAfter
break-inEvery
race
Every
third
(or
500 km)Every
fifth
(or
1,000 km)As re-
quiredRemarks

INSP
ADJ

PROGRAMME D’ENTRETIEN
FREINS
Régler la position du levier et la hauteur
de la pédale
Graisser les pivots
Contrôler la surface du disque de frein
Contrôler le niveau du liquide et les fuites
Resserrer les boulons du disque de frein,
les boulons d’étrier, les boulons du maî-
tre-cylindre et les boulons-raccords
Remplacer les plaquettes
Remplacer le liquide de frein
●
●
●
●
●●
●
●
●
●
●
●
Chaque année
FOURCHE AVANT
Contrôler et régler
Remplacer l’huile
Remplacer la bague d’étanchéité
●
●●
●
●
Huile de suspension “01”
BAGUE D’ETANCHEITE ET JOINT
ANTIPOUSSIERE DE FOURCHE
AVANT
Nettoyer et lubrifier
●●
Graisse à base de lithium
AMORTISSEUR ARRIERE
Contrôler et régler
Lubrifier
Resserrer
●
●●
●●
(Aprèscon-
duite sous la
pluie)
●
Graisse au bisulfure de
molybdène
GUIDE ET CYLINDRES DE CHAÎNE
D’ENTRAÎNEMENT
Contrôler
●●
BRAS OSCILLANT
Contrôler, lubrifier et resserrer
●●
Graisse au bisulfure de
molybdène
BRAS RELAIS, BIELLE
Contrôler, lubrifier et resserrer
●●
Graisse au bisulfure de
molybdène
TETE DE FOURCHE
Contrôler le jeu
Nettoyer et lubrifier
Remplacer le roulement
●●
●
●
Graisse à base de lithium
PNEUS, ROUES
Contrôler la pression de gonflage, le voile
de roue et l’usure des pneus et la tension
des rayons
Resserrer les boulons de la roue dentée
Contrôler les roulements
Remplacer les roulements
Graisser
●
●●
●
●
●●
Graisse à base de lithium
ACCELERATEUR, CABLES DE COM-
MANDE
Contrôler le cheminement et le branche-
ment
Graisser
Contrôler et nettoyer (câbles des gaz)
●
●
●●
●
●
Yamaha lube pour câble ou
huile moteur SAE 10W-30
Contrôler le degré de saleté
et d’usure des câbles des gaz
côté carburateur.
DEMARREUR A CHAUD, LEVIER
D’EMBRAYAGE
Inspecter le jeu
●
PartieAprès
rodageChaque
courseChaque
3ème (ou
500 km)Chaque
5ème (ou
1.000 km)Si
néces-
saireRemarques
3 - 3

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 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.3-13 ~ 16
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
Brakes Check the play of front brake and effect of front and rear brake. P.3-24 ~ 30
Drive chainCheck drive chain slack and alignment. Check that the drive
chain is lubricated properly.P.3-31 ~ 33
WheelsCheck for excessive wear and tire pressure. Check for loose
spokes and have no excessive play.P.3-41 ~ 42
SteeringCheck that the handlebar can be turned smoothly and have no
excessive play.P.3-42 ~ 43
Front forks and rear shock
absorberCheck that they operate smoothly and there is no oil leakage. P.3-33 ~ 40
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.4-3
Rear wheel sprocket Check that the rear wheel sprocket tightening bolt is not loose. P.3-31
Lubrication Check for smooth operation. Lubricate if necessary. P.3-44
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 - 7
INSP
ADJ
RADIATOR CAP INSPECTION
CAUTION:
Do not mix more than one type of ethyl-
ene glycol antifreeze containing corro-
sion inhibitors for aluminum engine.
Do not use water containing impurities or
oil.
7. Install:
Radiator cap
Start the engine and warm it up for a
several minutes.
8. Check:
Coolant level
Coolant level low → Add coolant. Handling notes of coolant:
The coolant is harmful so it should be han-
dled with special care.
WARNING
When coolant splashes to your eye.
Thoroughly wash your eye with water
and see your doctor.
When coolant splashes to your clothes.
Quickly wash it away with water and
then with soap.
When coolant is swallowed.
Quickly make him vomit and take him
to a doctor.
EC355000
RADIATOR CAP INSPECTION
1. Inspect:
Seal (radiator cap) 1
Valve and valve seat 2
Crack/damage → Replace.
Exist fur deposits 3 → Clean or
replace.

3 - 12
INSP
ADJ
AIR FILTER CLEANING
2. Clean:
Air filter element
Clean them with solvent.
NOTE:
After cleaning, remove the remaining solvent
by squeezing the element.
CAUTION:
Do not twist the element when squeezing
the element.
Leaving too much of solvent in the ele-
ment may result in poor starting.
3. Inspect:
Air filter element
Damage → Replace.
4. Apply:
Foam-air-filter oil or equivalent oil to the
element.
NOTE:
Squeeze out the excess oil. Element should
be wet but not dripping.
5. Install:
Air filter guide 1
NOTE:
Align the projection a on air filter guide with
the hole b in air filter element.
6. Apply:
Lithium soap base grease
On the matching surface a on air filter
element.

3 - 13
INSP
ADJ
7. Install:
Air filter element 1
Washer
Fitting bolt
NOTE:
Align the projection a on filter guide with the
hole b in air filter case.
T R..2 Nm (0.2 m · kg, 1.4 ft · lb)
ENGINE OIL LEVEL INSPECTION
1. Start the engine, warm it up for several
minutes, and then turn off the engine and
wait for five minutes.
2. Place the machine on a level place and
hold it up on upright position by placing
the suitable stand under the engine.
3. Remove:
Oil tank cap 1
1
4. Inspect:
Oil 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.
a
b
ENGINE OIL LEVEL INSPECTION