lock YAMAHA YZ250F 2001 Repair Manual

5 - 29
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.
ACHTUNG:CAUTION:
To prevent an accidental explosion of air,
the following instructions should be
observed:
lThe 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.
lBefore 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:
lFront 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:
lFront fork cap bolt 1
NOTE:
lWhile compressing the fork spring, set the
thin type spanners 2 between the spacer 3
and spring guide 4.
lHold the locknut 5 and remove the front fork
cap bolt.

5 - 29
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 folgende
Hinweise beachten.
lDer 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.
lVor dem Lösen der Verschluß-
schrauben unbedingt die Luft
aus den Gabelbeinen vollstän-
dig ablassen.
AUSBAU
Verschlußschraube
1. Demontieren:
lTelegabelverschlußschrau-
be 1
(vom Standrohr)
HINWEIS:
Die Verschlußschrauben vor der Te-
leskopgabel-Demontage lockern.
2. Demontieren:
lTelegabelverschlußschrau-
be 1
HINWEIS:
lDie Gabelfeder komprimieren und
dabei einen flachen Schlüssel 2
zwischen dem Distanzstück 3 und
dem Federsitz 4 ansetzen.
lDie 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:
lLa 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.
lAvant 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:
lBouchon 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:
lBouchon de tube de fourche 1
N.B.:
lTout en comprimant le ressort de four-
che, placer la clé à ergots fine 2 entre
l’entretoise 3 et le guide de ressort
4.
lMaintenir 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:
lLa 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.
lPrima 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:
lVite 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:
lVite mordente forcella ante-
riore 1
NOTA:
lComprimendo la molla della forcella,
inserire le chiavi di tipo sottile 2 tra il
distanziatore 3 e la guida della molla
4.
lMantenere il controdado 5 e rimuo-
vere la vite mordente della forcella
anteriore.

5 - 30
CHAS
EC553201
Inner tube
1. Remove:
lDust seal 1
lStopper ring 2
Using slotted-head screwdriver.
ACHTUNG:CAUTION:
Take care not to scratch the inner tube.
2. Remove:
lInner tube 1
Oil seal removal steps:
lPush in slowly a the inner tube just before
it bottoms out and then pull it back quickly
b.
lRepeat this step until the inner tube can
be pulled out from the outer tube.
EC553311
Damper rod
1. Remove:
lBase valve 1
lDamper rod 2
NOTE:
Use a damper rod holder 3 to lock the damper
rod.
EC554000
INSPECTION
EC554100
Damper rod
1. Inspect:
lDamper rod 1
Bend/damage ® Replace damper rod.
ACHTUNG: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 - 31
CHAS
EC554200
Base valve
1. Inspect:
lValve assembly 1
Wear/damage ® Replace.
lO-ring 2
Damage ® Replace.
EC554400
Fork spring
1. Measure:
lFork spring free length a
Out of specification ® Replace.
EC554502
Inner tube
1. Inspect:
lInner tube surface a
Score marks ® Repair or replace.
Use #1,000 grit wet sandpaper.
Damaged oil lock piece ® Replace.
lInner 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:
lOuter 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 - 32
CHAS
Front fork cap bolt
1. Inspect:
lFront fork cap bolt 1
lO-ring 2
lAir 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:
lDamper rod 1
To inner tube 2.
ACHTUNG: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:
lCopper washer 1
lO-ring 2
lBase valve 3
To inner tube 4.
4. Tighten:
lBase valve 1
NOTE:
lUse a damper rod holder 2 to lock the
damper rod 3.
lApply 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 - 33
CHASFRONT FORK
5. Install:
lSpring guide 1
lLocknut 2
To damper rod 3.
NOTE:
lInstall the spring guide with its cut a facing
upward.
lWith its thread b facing upward, fully finger
tighten the locknut onto the damper rod.
6. Install:
lDust seal 1
lStopper ring 2
lOil seal 3
lOil seal washer 4
lSlide metal 5
To inner tube 6.
NOTE:
lApply the fork oil on the inner tube.
lWhen installing the oil seal, use vinyl seat a
with fork oil applied to protect the oil seal lip.
lInstall the oil seal with its manufacture’s
marks or number facing the axle holder side.
7. Install:
lPiston metal 1
NOTE:
Install the piston metal onto the slot on inner
tube.
8. Install:
lOuter tube 1
To inner tube 2.

5 - 37
CHASFRONT FORK
21. Measure:
lDistance 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:
lRebound damping adjuster 1
NOTE:
lLoosen the rebound damping adjuster finger
tight.
lRecord the set position of the adjuster (the
amount of turning out the fully turned in posi-
tion).
23. Install
lCushion rubber 1
lWasher 2
lSpacer 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:
lPush rod 1
lFork spring 2
NOTE:
lInstall the fork spring with the damper rod 3
pulled up.
lAfter installing the fork spring, hold the
damper rod end so that it will not go down.
25. Install:
lFront fork cap bolt 1
Fully tighten the front fork cap bolt onto
the damper rod by hand.

5 - 38
CHASFRONT FORK
26. Tighten:
lFront fork cap bolt (locknut) 1
NOTE:
lWhile compressing the fork spring, set the
thin type spanners 2 between the spacer 3
and spring guide 4.
lHold the locknut 5 and tighten the front fork
cap bolt with specified torque.
27. Install:
lFront fork cap bolt 1
To outer tube.
NOTE:
Temporarily tighten the cap bolt.
T R..29 Nm (2.9 m · kg, 21 ft · lb)
28. Install:
lProtector guide 1
Installation
1. Install:
lFront fork 1
NOTE:
lTemporarily tighten the pinch bolts (lower
bracket).
lDo not tighten the pinch bolts (upper bracket)
yet.
2. Tighten:
lFront fork cap bolt 1
3. Adjust:
lFront fork top end a
Front fork top end (standard) a:
5 mm (0.20 in)
T R..30 Nm (3.0 m · kg, 22 ft · lb)

5 - 45
CHAS
LENKKOPF
Demontage-Arbeiten:1 Untere Gabelbrücke demontieren2 Lager demontieren
ANZUGSREIHENFOLGE:
lLenkerringmutter mit 38 Nm (3,8 m • kg) festziehen.lUm eine Umdrehung lockern.lNochmals mit 7 Nm (0,7 m • kg) festziehen.
Demontage-ArbeitenReihen-
folgeBauteil Anz. Bemerkungen
LENKKOPF DEMONTIEREN
WARNUNG
Das Motorrad gegen Umfallen sichern.Vorbereitung für den Ausbau Das Motorrad am Motor aufbocken
Nummernschild
Lenker
Kabelführung
Vorderrad-AbdeckungSiehe unter “LENKER”.
1 Lenkkopfmutter 1
2 Teleskopgabel 2 Siehe unter “TELESKOPGABEL”.
3 Obere Gabelbrücke 1
4 Lenkerringmutter 1 Spezialwerkzeug verwenden.
Siehe unter “AUSBAU”.
5 Untere Gabelbrücke 1
6 Lagerschutzkappe 1
7 Oberes Lager 1
8 Unteres Lager 1 Siehe unter “AUSBAU”.
9 Laufring 2 Siehe unter “AUSBAU”.
1
2
DIRECTION
LENKKOPF
STERZO
DIRECTION
Organisation de la dépose:1 Dépose du té inférieur2 Dépose du roulement
ETAPES DE SERRAGE:
lSerrer l’écrou crénelé de direction à un couple d’environ 38 Nm (3,8 m • kg, 27 ft • lb).lLe desserrer d’un tour.lLe resserrer à un couple d’environ 7 Nm (0,7 m • kg, 5,1 ft • lb)
Organisation de la dépose Ordre Nom de pièce Qté Remarques
DEPOSE DE LA DIRECTION
AVERTISSEMENT
Bien soutenir la machine afin qu’elle ne risquepas de se renverser.
Préparation pour la dépose Maintenir la machine en plaçant un support
approprié sous le moteur.
Plaque de numéro
Guidon
Guide de câble
Garde-boue avantSe reporter à la section “GUIDON”.
1 Ecrou de colonne de direction 1
2 Fourche avant 2 Se reporter à la section “FOURCHE AVANT”.
3 Té supérieur 1
4 Ecrou crénelé de direction 1 Utiliser l’outil spécial.
Se reporter à “POINTS DE DEPOSE”.
5 Té inférieur 1
6 Couvercle de cage à billes 1
7 Roulement supérieur 1
8 Roulement inférieur 1 Se reporter à “POINTS DE DEPOSE”.
9 Cage à billes 2 Se reporter à “POINTS DE DEPOSE”.
1
2
STERZO
Portata dello smontaggio:1 Rimozione della staffa inferiore 2 Rimozione del cuscinetto
OPERAZIONI DI SERRAGGIO:
lSerrare la ghiera. 38 Nm (3.8 m•kg, 27 ft•lb)
lAllentarla di un giro.
lRiserrarla. 7 Nm (0,7 m • kg, 5,1 ft • lb)
Portata dello smontaggio Ordine Denominazione Quantità Osservazioni
RIMOZIONE DELLO STERZO
AVVERTENZA
Sostenere saldamente il veicolo in modo che non ci siail rischio che si rovesci. Preparazione per la rimozione Mantenere il veicolo posizionando un supporto
idoneo sotto al motore.
Targa
Manubrio
Guidacavo
Parafango anterioreFare riferimento al paragrafo “MANUBRIO”.
1 Dado cannotto dello sterzo 1
2 Forcella anteriore 2Fare riferimento al paragrafo “FORCELLA ANTERIORE”.
3 Piastra superiore 1
4 Ghiera 1 Utilizzare l’utensile speciale.
Fare riferimento a “PUNTI DI RIMOZIONE”.
5 Piastra inferiore 1
6 Coperchio pista 1
7 Cuscinetto superiore 1
8 Cuscinetto inferiore 1 Fare riferimento a “PUNTI DI RIMOZIONE”.
9 Pista 2 Fare riferimento a “PUNTI DI RIMOZIONE”.
1
2

5 - 48
CHAS
4. Install:
lWasher 1
lSteering 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:
lWasher 1
7. Install:
lFront fork 1
lUpper bracket 2
NOTE:
lTemporarily tighten the pinch bolts (lower
bracket).
lDo not tighten the pinch bolts (upper bracket)
yet.
8. Install:
lWasher 1
lSteering stem nut 2
T R..145 Nm (14.5 m · kg, 105 ft · lb)
STEERING