2004 YAMAHA WR 250F warning

5 - 1
CHASFRONT WHEEL AND REAR WHEEL
EC500000
CHASSIS
EC590000
FRONT WHEEL AND REAR WHEEL
EC598000FRONT WHEEL
Extent of removal:
1 Front wheel removal
2 Wheel bearing removal
3 Brake disc removal
Extent of removal Order Part name Q’ty Remarks
FRONT WHEEL REMOVAL
WARNING
Support the machine securely so there is nodanger of it falling over. Preparation for removal Hold the machine by placing the suitable
stand under the engine.
1 Trip meter cable 1
2 Brake hose cover 1
3 Bolt (brake hose holder) 2 Only loosening.
4 Bolt (axle holder) 4 Only loosening.
5 Nut (front wheel axle) 1
6 Front wheel axle 1
7 Front wheel 1
8 Trip meter gear unit 1
9 Collar 1
10 Oil seal 1
11 Bearing 2 Refer to “REMOVAL POINTS”.
12 Brake disc 1
1
2
3
3

5 - 5
CHASFRONT WHEEL AND REAR WHEEL
EC598100REAR WHEEL
Extent of removal:
1 Rear wheel removal
2 Wheel bearing removal
3 Brake disc removal
Extent of removal Order Part name Q’ty Remarks
REAR WHEEL REMOVAL
WARNING
Support the machine securely so there is nodanger of it falling over. Preparation for removal Hold the machine by placing the suitable
stand under the engine.
1 Nut (rear wheel axle) 1
2 Rear wheel axle 1
3 Drive chain puller 2
4 Rear wheel 1 Refer to “REMOVAL POINTS”.
5 Collar 2
6 Rear wheel sprocket 1
7 Oil seal 2
8 Circlip 1
9 Bearing 2 Refer to “REMOVAL POINTS”.
10 Brake disc 1
1
2
3
3

5 - 11
CHASFRONT WHEEL AND REAR WHEEL
EC514200Wheel axle
1. Measure:
Wheel axle 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 axle.
Wheel axle bending
limit:
0.5 mm (0.020 in)
EC594200Brake disc
1. Measure:
Brake disc deflection
(only rear brake disc)
Use the dial gauge
1.
Out of specification
→ Inspect
wheel runout.
If wheel runout is in good con-
dition, replace the brake disc.
2. Measure:
Brake disc thickness
a
Out of limit
→ Replace.
Brake disc deflection
limit:
Rear:
:
0.15 mm (0.006 in)
Brake disc thickness:
Front:
3.0 mm (0.12 in)
:
2.5 mm (0.10 in)
Rear:
4.0 mm (0.16 in)
:
3.5 mm (0.14 in)
Axe de roue
1. Mesurer:
Déformation de l’axe de roue
Hors-spécification → Remplacer.
Utiliser le comparateur 1.
N.B.:
La valeur de déformation est égale à la
moitié de la lecture du comparateur.
AVERTISSEMENT
Ne jamais tenter de redresser un axe
tordu.
Limite de déformation de
l’axe de roue:
0,5 mm (0,020 in)
Disque de frein
1. Mesurer:
Déflexion de disque de frein (dis-
que de frein arrière uniquement)
Utiliser le comparateur 1.
Hors spécification → Examiner le
voile de roue.
Si le voile de la roue est normal,
changer le disque de frein.
2. Mesurer:
Epaisseur de disque de frein a
Hors limite → Remplacer.
Limite de déflexion de
disque de frein:
Arrière:
:
0,15 mm (0,006 in)
Epaisseur de disque de
frein:
Avant:
3,0 mm (0,12 in)
:
2,5 mm (0,10 in)
Arrière:
4,0 mm (0,16 in)
:
3,5 mm (0,14 in)
ROUE AVANT ET ROUE ARRIERE

5 - 23
CHASFRONT BRAKE AND REAR BRAKE
EC5A0000
FRONT BRAKE AND REAR BRAKE
EC5A8000FRONT BRAKE
Extent of removal:
1 Brake hose removal
2 Brake caliper removal
3 Brake master cylinder removal
Extent of removal Order Part name Q’ty Remarks
FRONT BRAKE REMOVAL
WARNING
Support the machine securely so there is nodanger of it falling over. Preparation for removal Hold the machine by placing the suitable
stand under the engine.
Drain the brake fluid. Refer to “REMOVAL POINTS”.
1 Brake hose cover 1
2 Brake hose holder 1
3 Bolt (brake hose holder) 2 Only loosening.
4 Union bolt 2
5 Brake hose 1
6 Pad pin plug 1 Remove when loosening the pad pin.
7 Pad pin 1 Loosen when disassembling the brake caliper.
8 Brake caliper 1
9 Brake lever 1
10 Brake master cylinder bracket 1
11 Brake master cylinder 1
1
2
2
3
3

5 - 27
CHASFRONT BRAKE AND REAR BRAKE
EC5A8100REAR BRAKE
Extent of removal:
1 Brake master cylinder removal
2 Brake hose removal
3 Brake caliper removal
Extent of removal Order Part name Q’ty Remarks
REAR BRAKE REMOVAL
WARNING
Support the machine securely so there is nodanger of it falling over. Preparation for removal Hold the machine by placing the suitable
stand under the engine.
Rear wheel Refer to “FRONT WHEEL AND REAR WHEEL”
section.
Drain the brake fluid. Refer to “REMOVAL POINTS”.
1 Brake pedal 1
2 Brake master cylinder 1
3 Brake hose holder 2
4 Union bolt 2
5 Brake hose 1
6 Pad pin plug 1 Remove when loosening the pad pin.
7 Pad pin 1 Loosen when disassembling the brake caliper.
8 Brake caliper 1
1
13
3
2

5 - 39
CHASFRONT BRAKE AND REAR BRAKE
EC5A3000REMOVAL POINTS
Brake fluid
1. Remove:
[Front]
Brake master cylinder cap
1
[Rear]
Brake master cylinder cap
1
Protector
NOTE:Do not remove the diaphragm.
ÈFront
ÉRear
È
É
2. Connect the transparent hose
2
to the bleed screw
1 and place a
suitable container under its end.
ÈFront
ÉRear
3. Loosen the bleed screw and
drain the brake fluid while pulling
the lever in or pushing down on
the pedal.
CAUTION:
Do not reuse the drained brake
fluid.
Brake fluid may erode painted
surfaces or plastic parts. Always
clean up spilled fluid immedi-
ately.
É È
Brake caliper piston
1. Remove:
Brake caliper piston
Use compressed air and pro-
ceed carefully.
WARNING
Cover piston with rag and use
extreme caution when expelling
piston from cylinder.
Never attempt to pry out piston.
ÈFront
ÉRear
Caliper piston removal steps:
Insert a piece of rag into the
brake caliper to lock one brake
caliper.
Carefully force the piston out of
the brake caliper cylinder with
compressed air.
È
É
POINTS DE DEPOSE
Liquide de frein
1. Déposer:
[Avant]
Couvercle de maître-cylindre de
frein 1
[Arrière]
Couvercle de maître-cylindre de
frein 1
Protection
N.B.:Ne pas enlever le diaphragme.
È
Avant
É
Arrière
2. Connecter le tuyau transparent 2 à
la vis de purge 1 et placer le réci-
pient approprié sous son extrémité.
È
Avant
É
Arrière
3. Desserrer la vis de purge et purger
le liquide de frein tout en rentrant le
levier ou en appuyant sur la pédale.
ATTENTION:
Ne pas réutiliser le liquide de frein
purgé.
Le liquide de frein attaque les surfa-
ces peintes et le plastique. Si on en
renverse, il faut l’essuyer immédia-
tement.
Piston d’étrier de frein
1. Déposer:
Piston d’étrier de frein
Appliquer de l’air comprimé en
effectuant délicatement cette opé-
ration.
AVERTISSEMENT
Recouvrir le piston d’un morceau
de tissu et faire très attention au
moment ou le piston est éjecté du
cylindre.
Ne jamais chasser le piston hors du
cylindre en faisant levier.
È
Avant
É
Arrière
Etapes de dépose des pistons
d’étrier:
Insérer un morceau de tissu dans
l’étrier pour bloquer un piston.
Chasser prudemment le piston du
cylindre de l’étrier avec de l’air
comprimé.
FREIN AVANT ET FREIN ARRIERE

5 - 41
CHASFRONT BRAKE AND REAR BRAKE
Brake caliper piston seal kit
1. Remove:
Dust seal
1
Piston seal
2
NOTE:Remove the piston seals and dust
seals by pushing them with a finger.
CAUTION:
Never attempt to pry out piston
seals and dust seals.
WARNING
Replace the piston seals and dust
seals whenever a caliper is disas-
sembled.
ÈFront
ÉRear
È
É
EC5A4000INSPECTION
Brake master cylinder
1. Inspect:
Brake master cylinder inner
surface
a
Wear/scratches
→ Replace
master cylinder assembly.
Stains
→ Clean.
WARNING
Use only new brake fluid.
ÈFront
ÉRear
É È
2. Inspect:
Diaphragm
1
Crack/damage
→ Replace.
ÈFront
ÉRear
É È
3. Inspect: (front brake only)
Reservoir float
1
Damage
→ Replace.
Kit de joint de piston d’étrier de frein
1. Déposer:
Joint antipoussière 1
Joint de piston 2
N.B.:
Déposer les joints de piston et antipous-
sière en les poussant avec le doigt.
ATTENTION:
Ne jamais chasser les joints de piston
et antipoussière hors du cylindre.
AVERTISSEMENT
Toujours changer les joints de piston
et antipoussière lors d’un démontage
d’étrier.
È
Avant
É
Arrière
CONTROLE
Maître-cylindre de frein
1. Contrôler:
Surface interne du maître-cylin-
dre de frein
a
Usure/rayures → Remplacer
l’ensemble maître-cylindre.
Taches → Nettoyer.
AVERTISSEMENT
Utiliser uniquement du liquide de
frein neuf.
È
Avant
É
Arrière
2. Contrôler:
Diaphragme 1
Craquelure/endommagement →
Remplacer.
È
Avant
É
Arrière
3. Contrôler: (frein avant seulement)
Flotteur de réservoir 1
Endommagement → Remplacer.
FREIN AVANT ET FREIN ARRIERE

5 - 43
CHASFRONT BRAKE AND REAR BRAKE
4. Inspect:
Brake master cylinder piston
1
Brake master cylinder cup
2
Wear/damage/score marks
→
Replace brake master cylinder
kit.
ÈFront
ÉRear
ÈÉ
Brake caliper
1. Inspect:
Brake caliper cylinder inner
surface
a
Wear/score marks
→ Replace
brake caliper assembly.
ÈFront
ÉRear
É È
2. Inspect:
Brake caliper piston
1
Wear/score marks
→ Replace
brake caliper piston assembly.
WARNING
Replace the piston seals and dust
seals 2
whenever a caliper is dis-
assembled.
EC534301Brake hose
1. Inspect:
Brake hose
1
Crack/damage
→ Replace.
EC5A5000ASSEMBLY AND INSTALLATION
WARNING
All internal parts should be
cleaned in new brake fluid only.
Internal parts should be lubri-
cated with brake fluid when
installed.
Replace the piston seals and
dust seals whenever a caliper is
disassembled.
Brake caliper piston
1. Clean:
Brake caliper
Piston seal
Dust seal
Brake caliper piston
Clean them with brake fluid.4. Contrôler:
Piston du maîgre-cylindre de
frein 1
Coupelle de cylindre du maître-
cylindre de frein 2
Usure/endommagement/rayures
→ Remplacer kit de maître-cylin-
dre de frein.
È
Avant
É
Arrière
Etrier de frein
1. Contrôler:
Surface interne du maître-cylin-
dre de frein
a
Usure/rayures → Remplacer
l’étrier de frein complet.
È
Avant
É
Arrière
2. Contrôler:
Piston d’étrier de frein 1
Usure/rayures → Remplacer le
piston d’étrier de frein complet.
AVERTISSEMENT
Toujours remplacer les joints de pis-
ton et les joints antipoussière 2 lors
d’un démontage d’étrier.
Durit de frein
1. Contrôler:
Durit de frein 1
Craquelure/endommagement →
Remplacer.
REMONTAGE ET MONTAGE
AVERTISSEMENT
Toutes les pièces internes doivent
être nettoyées en utilisant unique-
ment du liquide de frein.
Avant de les remonter, lubrifier les
pièces internes avec du liquide de frein.
Toujours changer les joints de pis-
ton et les joints antipoussière lors
d’un démontage d’étrier.
Piston d’étrier de frein
1. Nettoyer:
Etrier de frein
Joint de piston
Joint antipoussière
Piston d’étrier de frein
Les nettoyer avec du liquide de
frein.
FREIN AVANT ET FREIN ARRIERE