lock YAMAHA WR 250F 2002 Repair Manual

5 - 30
CHASFRONT FORK
EC556000
HANDLING NOTE
NOTE:
The front fork requires careful attention. So it is
recommended that the front fork be main-
tained at the dealers.
CAUTION:
To prevent an accidental explosion of air,
the following instructions should be
observed:
The front fork with a built-in piston rod
has a very sophisticated internal con-
struction and is particularly sensitive to
foreign material.
Use enough care not to allow any foreign
material to come in when the oil is
replaced or when the front fork is disas-
sembled and reassembled.
Before removing the cap bolts or front
forks, be sure to extract the air from the
air chamber completely.
EC553000
REMOVAL POINTS
Front fork cap bolt
1. Remove:
Front fork cap bolt 1
From the outer tube.
NOTE:
Before removing the front fork from the
machine, loosen the front fork cap bolt.
2. Remove:
Front fork cap bolt 1
NOTE:
While compressing the fork spring, set the
thin type spanners 2 between the spacer 3
and spring guide 4.
Hold the locknut 5 and remove the front fork
cap bolt.

5 - 30
CHAS
FOURCHE AVANT
TELESKOPGABEL
FORCELLA ANTERIORE
HANDHABUNGSHINWEIS
HINWEIS:
Die Teleskopgabel erfordert beson-
dere Aufmerksamkeit und sollte am
besten vom Yamaha-Händler gewar-
tet werden.
ACHTUNG:
Um einen plötzlichen Druckverlust
und damit verbundene Gefahren
zu vermeiden, unbedingt folgen-
de Hinweise beachten.
Der feine Teleskopgabel-Mecha-
nismus ist sehr auf Fremdstoffe
anfällig.
Deshalb beim Gabelölwechsel
sowie bei der Demontage und -
Montage darauf achten, daß
keine Fremdstoffe in die Tele-
skopgabel eindringen.
Vor dem Lösen der Verschluß-
schrauben unbedingt die Luft
aus den Gabelbeinen vollstän-
dig ablassen.
AUSBAU
Verschlußschraube
1. Demontieren:
Telegabelverschlußschrau-
be 1
(vom Standrohr)
HINWEIS:
Die Verschlußschrauben vor der Te-
leskopgabel-Demontage lockern.
2. Demontieren:
Telegabelverschlußschrau-
be 1
HINWEIS:
Die Gabelfeder komprimieren und
dabei einen flachen Schlüssel 2
zwischen dem Distanzstück 3 und
dem Federsitz 4 ansetzen.
Die Sicherungsmutter 5 gegenhal-
ten und die Verschlußschraube lö-
sen. REMARQUES CONCERNANT LA
MANIPULATION
N.B.:
La fourche avant nécessite une soi-
gneuse attention. Il est donc recom-
mandé de la faire entretenir chez le
revendeur.
ATTENTION:
Pour éviter une explosion accidentelle,
les instructions suivantes doivent être
observées:
La construction interne d’une four-
che avant à tige de piston incorpo-
rée est très sophistiquée et est
particulièrement sensible aux subs-
tances étrangères.
Faire suffisamment attention à ne
pas laisser pénétrer de substances
étrangères lorsque l’huile est rem-
placée ou lorsque la fourche avant
est démontée ou remontée.
Avant de dévisser les bouchons de
tube de fourche ou d’enlever les
bras de fourche avant, être sûr
d’avoir complètement purgé l’air
du réservoir d’air.
POINTS DE DEPOSE
Bouchon de tube de fourche
1. Déposer:
Bouchon de tube de fourche 1
Du fourreau.
N.B.:
Avant de démonter la fourche avant de la
machine, desserrer le bouchon de tube de
fourche.
2. Déposer:
Bouchon de tube de fourche 1
N.B.:
Tout en comprimant le ressort de four-
che, placer la clé à ergots fine 2 entre
l’entretoise 3 et le guide de ressort
4.
Maintenir le contre-écrou 5 et retirer
le bouchon de tube de fourche.NOTA PER LA MANIPOLAZIONE
NOTA:
La forcella anteriore richiede particolare
cautela. Pertanto si consiglia di affidare
la manutenzione della forcella anteriore
ai rivenditori.
ATTENZIONE:
Per impedire esplosioni di aria acci-
dentali, seguire le seguenti istruzioni:
La forcella anteriore con l’asta del
pistone incorporata ha una strut-
tura interna molto sofisticata ed è
particolarmente sensibile a corpi
estranei.
Fare molta attenzione a non far
penetrare materiale estraneo
durante il cambio dell’olio o quando
la forcella anteriore viene smontata
e rimontata.
Prima di rimuovere le viti senza
dado o le forcelle anteriori, accer-
tarsi di aver estratto completamente
l’aria dalla campana d’aria.
PUNTI DI RIMOZIONE
Vite mordente forcella anteriore
1. Rimuovere:
Vite mordente forcella ante-
riore 1
Dal fodero.
NOTA:
Prima di rimuovere la forcella anteriore
dal veicolo, allentare la vite mordente
della forcella anteriore.
2. Rimuovere:
Vite mordente forcella ante-
riore 1
NOTA:
Comprimendo la molla della forcella,
inserire le chiavi di tipo sottile 2 tra il
distanziatore 3 e la guida della molla
4.
Mantenere il controdado 5 e rimuo-
vere la vite mordente della forcella
anteriore.

5 - 31
CHAS

EC553201
Inner tube
1. Remove:

Dust seal
1


Stopper ring
2

Using slotted-head screwdriver.
CAUTION:

Take care not to scratch the inner tube.
2. Remove:

Inner tube
1

Oil seal removal steps:

Push in slowly
a
the inner tube just before
it bottoms out and then pull it back quickly
b
.

Repeat this step until the inner tube can
be pulled out from the outer tube.
EC553311
Damper rod
1. Remove:

Base valve
1


Damper rod
2

NOTE:

Use a damper rod holder
3
to lock the damper
rod.
EC554000
INSPECTION
EC554100
Damper rod
1. Inspect:

Damper rod
1

Bend/damage
→
Replace damper rod.
CAUTION:

The front fork with a built-in piston rod has
a very sophisticated internal construction
and is particularly sensitive to foreign
material.
Use enough care not to allow any foreign
material to come in when the oil is replaced
or when the front fork is disassembled and
reassembled.
Damper rod holder:
YM-1423/90890-01423
FRONT FORK

5 - 32
CHAS

EC554200
Base valve
1. Inspect:

Valve assembly
1

Wear/damage
→
Replace.

O-ring
2

Damage
→
Replace.
EC554400
Fork spring
1. Measure:

Fork spring free length
a

Out of specification
→
Replace.
EC554502
Inner tube
1. Inspect:

Inner tube surface
a

Score marks
→
Repair or replace.
Use #1,000 grit wet sandpaper.
Damaged oil lock piece
→
Replace.

Inner tube bends
Out of specification
→
Replace.
Use the dial gauge
1
.
NOTE:

The bending value is shown by one half of the
dial gauge reading.
WARNING

Do not attempt to straighten a bent inner
tube as this may dangerously weaken the
tube.
EC554600
Outer tube
1. Inspect:

Outer tube
1

Score marks/wear/damage
→
Replace.
Fork spring free length:
460 mm (18.1 in)
: 455 mm (17.9 in)
Inner tube bending limit:
0.2 mm (0.008 in)
FRONT FORK

5 - 33
CHAS

Front fork cap bolt
1. Inspect:

Front fork cap bolt
1


O-ring
2


Air bleed screw
3

Wear/damage
→
Replace.
FRONT FORK
EC555000
ASSEMBLY AND INSTALLATION
Front fork assembly
1. Wash the all parts in a clean solvent.
2. Install:

Damper rod
1

To inner tube
2
.
CAUTION:

To install the damper rod into the inner
tube, hold the inner tube aslant. If the inner
tube is held vertically, the damper rod may
fall into it, damaging the valve inside.
3. Install:

Copper washer
1


O-ring
2
Base valve 3
To inner tube 4.
4. Tighten:
Base valve 1
NOTE:
Use a damper rod holder 2 to lock the
damper rod 3.
Apply the LOCTITE® on the base valve
thread.
Damper rod holder:
YM-1423/90890-01423
T R..55 Nm (5.5 m · kg, 40 ft · lb)

5 - 34
CHASFRONT FORK
5. Install:
Spring guide 1
Locknut 2
To damper rod 3.
NOTE:
Install the spring guide with its cut a facing
upward.
With its thread b facing upward, fully finger
tighten the locknut onto the damper rod.
6. Install:
Dust seal 1
Stopper ring 2
Oil seal 3
Oil seal washer 4
Slide metal 5
To inner tube 6.
NOTE:
Apply the fork oil on the inner tube.
When installing the oil seal, use vinyl seat a
with fork oil applied to protect the oil seal lip.
Install the oil seal with its manufacture’s
marks or number facing the axle holder side.
7. Install:
Piston metal 1
NOTE:
Install the piston metal onto the slot on inner
tube.
8. Install:
Outer tube 1
To inner tube 2.

5 - 38
CHASFRONT FORK
21. Measure:
Distance a
Out of specification → Turn into the
locknut.
Distance a:
20 mm (0.79 in) or more
Between damper rod 1 top and
locknut 2 top.
22. Loosen:
Rebound damping adjuster 1
NOTE:
Loosen the rebound damping adjuster finger
tight.
Record the set position of the adjuster (the
amount of turning out the fully turned in posi-
tion).
23. Install
Cushion rubber 1
Washer 2
Spacer 3
To front fork cap bolt 4.
NOTE:
Install the cushion rubber with its smaller
dia.end a facing the front fork cap bolt.
24. Install:
Push rod 1
Fork spring 2
NOTE:
Install the fork spring with the damper rod 3
pulled up.
After installing the fork spring, hold the
damper rod end so that it will not go down.
25. Install:
Front fork cap bolt 1
Fully tighten the front fork cap bolt onto
the damper rod by hand.

5 - 39
CHASFRONT FORK
26. Tighten:
Front fork cap bolt (locknut) 1
NOTE:
While compressing the fork spring, set the
thin type spanners 2 between the spacer 3
and spring guide 4.
Hold the locknut 5 and tighten the front fork
cap bolt with specified torque.
T R..29 Nm (2.9 m · kg, 21 ft · lb)
27. Install:
Front fork cap bolt 1
To outer tube.
NOTE:
Temporarily tighten the cap bolt.
28. Install:
Protector guide 1
Installation
1. Install:
Front fork 1
NOTE:
Temporarily tighten the pinch bolts (lower
bracket).
Do not tighten the pinch bolts (upper bracket) yet.
2. Tighten:
Front fork cap bolt 1
3. Adjust:
Front fork top end a
* For EUROPE
** For AUS, NZ and ZA
Front fork top end (standard) a:
5 mm (0.20 in)
* 8 mm (0.31 in)
** 10.5 mm (0.41 in)
T R..30 Nm (3.0 m · kg, 22 ft · lb)

5 - 48
CHAS
ETAPES DE SERRAGE:Serrer l’écrou crénelé de direction à un couple d’environ 38 Nm (3,8 m • kg, 27 ft • lb).Le desserrer d’un tour.Le resserrer à un couple d’environ 7 Nm (0,7 m • kg, 5,1 ft • lb)
Organisation de la dépose Ordre Nom de pièce QtéRemarques
8 Roulement supérieur 1
9 Roulement inférieur 1 Se reporter à “POINTS DE DEPOSE”.
10Cage à billes
2Se reporter à “POINTS DE DEPOSE”.
2
ANZUGSREIHENFOLGE:
Lenkerringmutter mit 38 Nm (3,8 m • kg) festziehen.Um eine Umdrehung lockern.Nochmals mit 7 Nm (0,7 m • kg) festziehen.
Demontage-ArbeitenReihen-
folgeBauteil Anz. Bemerkungen
8 Oberes Lager 1
9 Unteres Lager 1 Siehe unter “AUSBAU”.
10Laufring
2Siehe unter “AUSBAU”.
2
OPERAZIONI DI SERRAGGIO:
Serrare la ghiera. 38 Nm (3,8 m • kg, 27 ft • lb)
Allentarla di un giro.
Riserrarla. 7 Nm (0,7 m • kg, 5,1 ft • lb)
Portata dello smontaggio Ordine Denominazione QuantitàOsservazioni
8 Cuscinetto superiore 1
9 Cuscinetto inferiore 1 Fare riferimento a “PUNTI DI RIMOZIONE”.
10 Pista 2 Fare riferimento a “PUNTI DI RIMOZIONE”.
2
DIRECTION
LKKOPF
STERZO

5 - 51
CHAS
4. Install:
Washer 1
Steering ring nut 2
Tighten the steering ring nut using the
steering nut wrench 3.
Refer to “STEERING HEAD INSPEC-
TION AND ADJUSTMENT” section in
the CHAPTER 3.
T R..7 Nm (0.7 m · kg, 5.1 ft · lb)
5. Check the steering stem by turning it lock
to lock. If there is any binding, remove
the steering stem assembly and inspect
the steering bearings.
6. Install:
Washer 1
7. Install:
Front fork 1
Upper bracket 2
NOTE:
Temporarily tighten the pinch bolts (lower
bracket).
Do not tighten the pinch bolts (upper bracket)
yet.
8. Install:
Washer 1
Steering stem nut 2
T R..145 Nm (14.5 m · kg, 105 ft · lb)
STEERING