2002 YAMAHA WR 250F oil

3 - 49
INSP
ADJ
REPLACING THE HEADLIGHT BULBS
REPLACING THE HEADLIGHT BULBS
1. Remove:
Headlight
Refer to “SEAT, FUEL TANK AND
SIDE COVERS” section in the CHAP-
TER 4.
2. Remove:
Headlight bulb holder cover 1
3. Detach:
Headlight bulb holder 1
4. Remove:
Headlight bulb 2
WARNING
Since the headlight bulb gets extremely
hot, keep flammable products and your
hands away from the bulb unit it has
cooled down.
5. Install:
Headlight bulb
Secure the new headlight bulb with the
headlight bulb holder.
CAUTION:
Avoid touching the glass part of the head-
light bulb to keep it free form oil, otherwise
the transparency of the glass, the life of the
bulb and the luminous flux will be
adversely affected. If the headlight bulb
gets soiled, thoroughly clean it with a cloth
moistened with alcohol or lacquer thinner.
6. Attach:
Headlight bulb holder
7. Install:
Headlight bulb holder cover
8. Install:
Headlight bolt (left and right)
Headlight bolt (lower)
Refer to “SEAT, FUEL TANK AND
SIDE COVERS” section in the CHAP-
TER 4.
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
T R..7 Nm (0.7 m · kg, 5.1 ft · lb)

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

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ENGCAMSHAFTS
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) 5 in a
crisscross 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.
With the rod fully wound and the chain
tensioner UP mark a facing upward,
install the gasket 1 and the timing chain
tensioner 2, and tighten the bolt 3 to the
specified torque.
T R..
Bolt (timing chain tensioner):
10 Nm (1.0 m • kg, 7.2 ft • lb)

4 - 29
ENG
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

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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 Decompression cable guide 1
3 Oil delivery pipe 1
4 Nut 2
5 Bolt [L=135 mm (5.31 in)] 2
6 Bolt [L=145 mm (5.71 in)] 2
7 Cylinder head 1 Disconnect the decompression cable.
8 Timing chain guard (exhaust side) 1
9 Bolt (decompression shaft) 1
10 Decompression shaft 1
1

ENG
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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.
CULASSE
ZYLINDERKOPF
TESTATA DEL CILINDRO

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ENG

CYLINDER HEAD
ASSEMBLY AND INSTALLATION
Cylinder head
1. Install:

Decompression shaft
1


Copper washer
2

Bolt (decompression shaft)
3

NOTE:

Apply the engine oil on the decompression
shaft.
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)

2. Install:

Dowel pin
1


Cylinder head gasket
2


Timing chain guide (exhaust side)
3


Decompression cable
4


Cylinder head
5

NOTE:


Install the decompression cable to the cylin-
der head, and then to the cylinder.

While pulling up the timing chain, install the
timing chain guide (exhaust side) and cylin-
der head.

4 - 33
ENG

3. Install:

Washer
1


Cable guide
2


Bolts [L=145 mm (5.71 in)]
3


Bolts [L=135 mm (5.31 in)]
4


Nuts
5

NOTE:


Apply the molybdenum disulfide grease on
the thread and contact surface of the bolts.

Follow the numerical order shown in the illus-
tration. Tighten the bolts and nuts in two
stages.
T R..38 Nm (3.8 m · kg, 27 ft · lb)
T R..38 Nm (3.8 m · kg, 27 ft · lb)
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)

4. Install:

Copper washer
1

Oil delivery pipe
2


Union bolt (M8)
3


Union bolt (M10)
4

T R..18 Nm (1.8 m · kg, 13 ft · lb)
T R..20 Nm (2.0 m · kg, 14 ft · lb)

5. Install:

Decompression cable guide
1


Bolt (decompression cable guide)
2

T R..10 Nm (1.0 m · kg, 7.2 ft · lb)

6. Install:

Radiator pipe
1


Bolt (radiator pipe)
2
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
CYLINDER HEAD