2003 YAMAHA YZ250F oil

INSP
ADJ
CONTROLE DE PRESSION DES PNEUS/CONTROLE ET SERRAGE DES RAYONS/
CONTROLE DE LA ROUE
REIFENLUFTDRUCK KONTROLLIEREN/SPEICHEN KONTROLLIEREN UND
FESTZIEHEN/RÄDER KONTROLLIEREN
CONTROLLO DELLA PRESSIONE DEI PNEUMATICI/ISPEZIONE E SERRAGGIO DEI
RAGGI/ISPEZIONE DELLE RUOTE
REIFENLUFTDRUCK KONTROL-
LIEREN
1. Messen:
Reifenluftdruck
Unvorschriftsmäßig → Ein-
stellen.
HINWEIS:
Den Reifenluftdruck bei kalten Rei-
fen kontrollieren.
Bei zu niedrigem Reifendruck liegt
die Reifenwulst nicht fest an, was
dazu führen kann, daß sich der
Reifen von der Felge löst.
Ein geneigter Reifenventilschaft
deutet an, daß der Reifen ver-
rutscht ist.
Bei geneigtem Reifenventilschaft
muß die Reifenposition berichtigt
werden.
Standard-Reifenluft-
druck
100 kPa (1,0 bar)
SPEICHEN KONTROLLIEREN UND
FESTZIEHEN
1. Kontrollieren:
Speichen 1
Verzug/Beschädigung →
Erneuern.
Speichen locker → Nach-
spannen.
2. Festziehen:
Speichen
HINWEIS:
Die Speichen müssen vor und nach
dem Einfahren nachgezogen wer-
den. Nach jeder Übungsfahrt bzw.
Rennen die Speichenspannung prü-
fen.
T R..3 Nm (0.3 m · kg)
RÄDER KONTROLLIEREN
1. Messen:
Felgenschlag
Das Rad anheben und dre-
hen.
Übermäßig → Erneuern. CONTROLE DE PRESSION DES
PNEUS
1. Mesurer:
Pression des pneus
Hors spécification → Régler.
N.B.:
Vérifier le pneu alors qu’il est froid.
Des butées de bourrelet lâches permet-
tent au pneu de se détacher de sa posi-
tion sur la jante lorsque la pression des
pneus est basse.
Une tige de soupape de pneu inclinée
indique que le pneu se détache de sa
position sur la jante.
Si la tige de soupape de pneu est incli-
née, le pneu a tendance à se détacher
de sa position. Corriger 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.
Rayons desserrés → Resserrer.
2. Serrer:
Rayon
N.B.:
Ne pas oublier de retendre les rayons
avant et après le rodage. Après un entraî-
nement ou une course, contrôler si les
rayons ne sont pas détendus.
T R..3 Nm (0,3 m · kg, 2,2 ft · lb)
CONTROLE DE LA ROUE
1. Mesure:
Voile de roue
Soulever la roue et la tourner.
Voile excessif → Remplacer.CONTROLLO DELLA PRESSIONE
DEI PNEUMATICI
1. Misurare:
Pressione dei pneumatici
Fuori specifica → Regolare.
NOTA:
Controllare i pneumatici a freddo.
I fermi del tallone consentono alla
ruota di scivolare dalla sua posizione
sul cerchio quando la pressione dei
pneumatici è bassa.
Uno stelo della valvola inclinato
indica che il pneumatico scivola dalla
sua posizione sul cerchione.
Se lo stelo della valvola è inclinato,
indica che il pneumatico ha la ten-
denza a scivolare fuori posizione. Cor-
reggere la posizione dei pneumatici.
Pressione standard pneu-
matici:
100 kPa
(1,0 kgf/cm
2, 15 psi)
ISPEZIONE E SERRAGGIO DEI
RAGGI
1. Ispezionare:
Raggi 1
Deformazione/danno → Sosti-
tuire.
Raggi allentati → Serrare.
2. Serrare:
Raggi
NOTA:
Accertarsi di serrare i raggi prima e dopo
il rodaggio. Dopo un allenamento o una
gara controllare l’eventuale allentamento
dei raggi.
T R..3 Nm (0,3 m · kg, 2,2 ft · lb)
ISPEZIONE DELLE RUOTE
1. Ispezionare:
Scentratura
Sollevare la ruota e farla girare.
Scentratura anomala → Sosti-
tuirla.
3 - 41

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 endÅUse Yamaha cable lube or equivalent on these
areas.
ıUse SAE 10W-30 motor oil or suitable chain
lubricants.
ÇLubricate 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

4 - 21
ENGCAMSHAFTS
CAMSHAFTS
CYLINDER HEAD COVER
Extent of removal:1 Cylinder head cover removal
Extent of removal Order Part name Q’ty Remarks
CYLINDER HEAD COVER
REMOVAL
Preparation for removal Seat and fuel tank Refer to “SEAT, FUEL TANK AND SIDE
COVERS” section.
Carburetor Refer to “CARBURETOR” section.
1 Spark plug 1
2 Cylinder head breather hose 1
3 Oil tank breather hose 1
4 Bolt (cylinder head cover) 2
5 Cylinder head cover 1
6 Cylinder head cover gasket 1
7Timing chain guide (top side)
1
1

4 - 26
ENGCAMSHAFTS
Decompression system
1. Check:
Decompression system
Checking steps:
Check that the decompression mecha-
nism cam 1 moves smoothly.
Check that the decompression mechanism
cam lever pin 2 projects from the camshaft.
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
clockwise.
When releasing the screwdriver by
pressing 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
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 - 27
ENGCAMSHAFTS
Fit the timing chain 3 onto both camshaft
sprockets and install the camshafts on the
cylinder head.
NOTE:
The camshafts should be installed onto the
cylinder head so that the punch mark c on
the exhaust camshaft and the punch mark
d on the intake camshaft must align with
the cylinder head surface, as shown in the
illustration.
CAUTION:
Do not turn the crankshaft during the
camshaft installation. Damage or
improper valve timing will result.
Install the clips, camshaft caps 4 and
bolts (camshaft cap) 5.
T R..
Bolt (camshaft cap):
10 Nm (1.0 m • kg, 7.2 ft • lb)
NOTE:
Before removing the clips, cover the cylin-
der head with a clean rag to prevent the
clips from into the cylinder head cavity.
Apply the engine oil on the thread and con-
tact surface of the bolts (camshaft cap).
Tighten the bolts (camshaft cap) in a criss-
cross pattern.
CAUTION:
The bolts (camshaft cap) must be tight-
ened evenly, or damage to the cylinder
head, camshaft caps, and camshaft will
result.
2. Install:
Timing chain tensioner
Installation steps:
While pressing the tensioner rod lightly
with fingers, use a thin screwdriver and
wind the tensioner rod up fully clockwise.

4 - 29
ENG
6. Install:
Timing chain guide (top side) 1
Cylinder head cover gasket 2
Cylinder head cover 3
Bolt (cylinder head cover) 4
NOTE:
Apply the sealant on the cylinder head cover
gasket.
Quick gasket®:
ACC-QUICK-GS-KT
YAMAHA Bond No. 1215:
90890-85505
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
7. Install:
Oil tank breather hose
Cylinder head breather hose
Spark plug
T R..13 Nm (1.3 m · kg, 9.4 ft · lb)
CAMSHAFTS

4 - 30
ENGCYLINDER HEAD
CYLINDER HEAD
Extent of removal:1 Cylinder head removal
Extent of removal Order Part name Q’ty Remarks
CYLINDER HEAD REMOVAL
Preparation for removal Seat and fuel tank Refer to “SEAT, FUEL TANK AND SIDE
COVERS” section.
Exhaust pipe and silencer Refer to “EXHAUST PIPE AND
SILENCER” section.
Radiator hose 1 Disconnect at cylinder head side.
Carburetor Refer to “CARBURETOR” section.
Camshaft Refer to “CAMSHAFTS” section.
Upper engine bracket Refer to “ENGINE REMOVAL” section.
1 Radiator pipe 1
2 Oil delivery pipe 1
3 Nut 2
4 Bolt [L=135 mm (5.31 in)] 2
5 Bolt [L=145 mm (5.71 in)] 2
6 Cylinder head 1
7 Timing chain guard (exhaust side) 1
1

ENG
4 - 31
CULASSE
ZYLINDERKOPF
TESTATA DEL CILINDRO
PRÜFUNG
Zylinderkopf
1. Entfernen:
Ölkohleablagerungen (im
Brennraum)
Einen abgerundeten Scha-
ber verwenden.
HINWEIS:
Keine scharfkantigen Gegenstände
benutzen, um Beschädigungen und
Kratzer an folgenden Stellen zu ver-
meiden:
Zündkerzenbohrung
Ventilsitze
2. Kontrollieren:
Zylinderkopf
Kratzer/Beschädigungen →
Erneuern.
3. Messen:
Zylinderkopf-Verzug
Grenzwert überschritten →
Planschleifen.
Zylinderkopf-Verzugs-
grenze
unter 0,05 mm
Arbeitsschritte
Lineal und Fühlerlehre über den
Zylinderkopf legen.
Verzug mit der Fühlerlehre
messen.
Ist die Verzugsgrenze über-
schritten, den Zylinderkopf
planschleifen.
Den Zylinderkopf mit Naßschleif-
papier (Körnung 400–600) auf ei-
ner planen Platte in einer Achter-
bewegung abschleifen.
HINWEIS:
Den Zylinderkopf mehrmals dre-
hen, um eine ebene Oberfläche
zu gewährleisten.
CONTROLE
Culasse
1. Eliminer:
Dépôt de calamine
(de la chambre de combustion)
Utiliser un grattoir arrondi.
N.B.:
Ne pas utiliser d’instrument pointu pour
éviter d’endommager ou de rayer:
Filets de bougies
Sièges de soupape
2. Contrôler:
Culasse
Rayures/endommagement →
Remplacer.
3. Mesurer:
Déformation de la culasse
Hors spécifications → Surfa-
cer.
Limite de déformation de
la culasse:
Moins de 0,05 mm
(0,002 in)
Etapes de la mesure de la limite de
déformation et du surfaçage:
Placer une règle et une jauge
d’épaisseur sur la culasse.
Utiliser une jauge d’épaisseur pour
mesurer la déformation.
Si la déformation est hors spécifi-
cations, surfacer la culasse.
Mettre un morceau de toile émeri
n˚ 400 à 600 humide sur une pla-
que à surfacer et surfacer la culasse
en décrivant des “huit”.
N.B.:
Tourner la culasse plusieurs fois pour
obtenir une surface lisse.
ISPEZIONE
Testata del cilindro
1. Eliminare:
Depositi carboniosi (dalle
camere di combustione)
Utilizzare un raschietto arro-
tondato.
NOTA:
Non utilizzare uno strumento appuntito
per evitare di danneggiare o di graffiare:
Filettature candela di accensione
Sedi delle valvole
2. Ispezionare:
Testata del cilindro
Graffi/danno → Sostituire.
3. Misurare:
Deformazione testata del cilin-
dro
Fuori specifica → Spianare.
Deformazione della testata
del cilindro:
Meno di 0,05 mm
(0,002 in)
Misurazione della deformazione e
fasi per lo spianamento:
Posizionare un guardapiano ed uno
spessimetro sulla testata del cilin-
dro.
Utilizzare uno spessimetro per
misurare la deformazione.
Se la deformazione è fuori speci-
fica, spianare la testata del cilindro.
Posizionare carta vetrata di grana
400 ~ 600 umida su un piano di
riscontro e spianare la testata con
un movimento a otto.
NOTA:
Per ottenere una superficie uniforme,
ruotare la testata del cilindro diverse
volte.