lock YAMAHA YZ250LC 2004 Service Manual

5-28
CHASFRONT FORK
EC556000
HANDLING NOTE
NOTE:
The front fork requires careful attention. So it is
recommended that the front fork be maintained
at the dealers.
cC
To prevent an accidental explosion of air,
the following instructions should be ob-
served:
9The 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 re-
placed or when the front fork is disassem-
bled and reassembled.
9Before removing the cap bolts or front
forks, be sure to extract the air from the air
chamber completely.
EC553000
REMOVAL POINTSEC553160
Cap bolt
1. Remove:
9Cap bolt 1
From the outer tube.
NOTE:
Before removing the front fork from the machine,
loosen the cap bolt.
2. Remove:
9Cap bolt 1
NOTE:
Hold the locknut 2and remove the cap bolt.
5XF-9-30-5B 5/10/03 8:54 AM Page 6

5-29
CHASFRONT FORK
EC553201
Inner tube
1. Remove:
9Dust seal 1
9Stopper ring 2
Using slotted-head screwdriver.
cC
Take care not to scratch the inner tube.
2. Remove:
9Inner tube 1
EC553311
Damper rod
1. Remove:
9Base valve 1
9Damper rod 2
NOTE:
Use a damper rod holder 3to lock the
damper rod.
EC554000
INSPECTIONEC554100
Damper rod
1. Inspect:
9Damper rod 1
Bend/DamageReplace damper rod.
cC
The front fork with a built-in piston rod has
a very sophisticated internal construction
and is particularly sensitive to foreign ma-
terial.
Use enough care not to allow any foreign
material to come in when the oil is re-
placed or when the front fork is disassem-
bled and reassembled.
Oil seal removal steps:
9Push in slowly athe inner tube just be-
fore it bottoms out and then pull it back
quickly b.
9Repeat this step until the inner tube can
be pulled out from the outer tube.
Damper rod holder:
YM-01494/90890-01494
5XF-9-30-5B 5/10/03 8:54 AM Page 8

5-30
CHASFRONT FORK
EC554200
Base valve
1. Inspect:
9Valve assembly 1
Wear/DamageReplace.
9O-ring 2
DamageReplace.
EC554400
Fork spring
1. Measure:
9Fork spring free length a
Out of specificationReplace.
EC554502
Inner tube
1. Inspect:
9Inner tube surface a
Score marksRepair or replace.
Use #1,000 grit wet sandpaper.
Damaged oil lock pieceReplace.
9Inner tube bends
Out of specificationReplace.
Use the dial gauge 1.
NOTE:
The bending value is shown by one half of the
dial gauge reading.
w
Do not attempt to straighten a bent inner
tube as this may dangerously weaken the
tube.
EC554600
Outer tube
1. Inspect:
9Outer tube 1
Score marks/Wear/DamageReplace.
Standard
479 mm 474 mm
(18.9 in) (18.7 in)Fork spring free length:
Inner tube bending limit:
0.2 mm (0.008 in)
5XF-9-30-5B 5/10/03 8:54 AM Page 10

5-31
CHASFRONT FORK
EC554700
Cap bolt
1. Inspect:
9Cap bolt 1
9O-ring 2
9Air bleed screw 3
Wear/DamageReplace.
EC555000
ASSEMBLY AND INSTALLATIONEC5551D0
Front fork assembly
1. Wash the all parts in a clean solvent.
2. Install:
9Damper rod 1
To inner tube 2.
cC
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:
9Copper washer 1
9O-ring 2
9Base valve 3
To inner tube 4.
4. Tighten:
9Base valve 1
NOTE:
9Use a damper rod holder 2to lock the damper
rod 3.
9Apply the LOCTITE
®on the base valve thread.
Damper rod holder:
YM-01494/90890-01494
55 Nm (5.5 m•kg, 40 ft•lb)
5XF-9-30-5B 5/10/03 8:54 AM Page 12

5-32
CHASFRONT FORK
5. Install:
9Spring guide 1
9Locknut 2
To damper rod 3.
NOTE:
9Install the spring guide with its smaller dia. end
afacing downward.
9With its thread bfacing upward, fully finger
tighten the locknut onto the damper rod.
6. Install:
9Dust seal 1
9Stopper ring 2
9Oil seal 3
9Oil seal washer 4
9Slide metal 5
To inner tube 6.
NOTE:
9Apply the fork oil on the inner tube.
9When installing the oil seal, use vinyl seat a
with fork oil applied to protect the oil seal lip.
9Install the oil seal with its manufacture's marks
or number facing the axle holder side.
9Install the oil seal washer with its projections b
facing upward.
7. Install:
9Piston metal 1
NOTE:
Install the piston metal onto the slot on inner
tube.
8. Install:
9Outer tube 1
To inner tube 2.
5XF-9-30-5B 5/10/03 8:54 AM Page 14

5-36
CHASFRONT FORK
21. Measure:
9Distance a
Out of specificationTurn into the locknut.
23. Install:
9Push rod 1
9Fork spring 2
NOTE:
9Install the fork spring with the damper rod 3
pulled up.
9After installing the fork spring , hold the damper
rod end so that it will not go down.
24. Install:
9Spring seat 1
9Cap bolt 2
NOTE:
Fully finger tighten the cap bolt onto the damper
rod.
22. Loosen:
9Rebound damping adjuster 1
NOTE:
9Loosen the rebound damping adjuster finger
tight.
9Record the set position of the adjuster (the
amount of turning out the fully turned in posi-
tion).
Distance a a
:
19 mm (0.75 in) or more
Between damper rod 1 1
top and
locknut 2 2
top.
25. Tighten:
9Cap bolt (locknut) 1
NOTE:
Hold the locknut 2and tighten the cap bolt with
specified torque.
29 Nm (2.9 m•kg, 21 ft•lb)
5XF-9-30-5B 5/10/03 8:54 AM Page 22

5-49
CHASSTEERING
4. Install:
9Ring nut 1
Tighten the ring nut using the ring nut
wrench 2.
Refer to “STEERING HEAD INSPECTION
AND ADJUSTMENT” section in the CHAP-
TER 3.
5. Check the steering shaft by turning it lock to
lock. If there is any binding, remove the
steering shaft assembly and inspect the
steering bearings.
6. Install:
9Plain washer 1
7. Install:
9Front fork 1
9Handle crown 2
NOTE:
9Temporarily tighten the pinch bolts (under
bracket).
9Do not tighten the pinch bolts (handle crown)
yet.
8. Install:
9Plain washer 1
9Steering shaft nut 2
7 Nm (0.7 m•kg, 5.1 ft•lb)
145 Nm (14.5 m•kg, 105 ft•lb)
5XF-9-30-5C 5/6/03 6:39 PM Page 22

5-59
CHASREAR SHOCK ABSORBER
Extent of removal Order Part name Q’ty Remarks
REAR SHOCK ABSORBER
REMOVAL
Preparation forHold the machine by placing the
removalsuitable stand under the engine.
SeatRefer to “SEAT, FUEL TANK AND
SIDE COVERS” section.
SilencerRefer to “EXHAUST PIPE AND
SILENCER” section.
1 Clamp (air cleaner joint) 1 Loosen the screw (air cleaner joint).
2 Rear frame 1
3
Bolt (rear shock absorber-relay arm)1 Hold the swingarm.
4 Bolt (rear shock absorber-frame) 1
5 Rear shock absorber 1
6 Locknut 1
7 Adjuster 1
8 Spring guide (lower) 1
9 Spring guide (upper) 1
10 Spring (rear shock absorber) 1
11 Bearing 2 Refer to “REMOVAL POINTS”.
2
w
Support the machine securely so there is no dan-
ger of it falling over.
Extent of removal:1Rear shock absorber removal 2Rear shock absorber disassembly
1
56 Nm (5.6 m•kg, 40 ft•lb)
53 Nm (5.3 m•kg, 38 ft•lb)
32 Nm (3.2 m•kg, 23 ft•lb)
EC580000
REAR SHOCK ABSORBER
29 Nm (2.9 m•kg, 21 ft•lb)
5XF-9-30-5D 5/6/03 6:37 PM Page 18

5-63
CHASREAR SHOCK ABSORBER
EC5852B5
Rear shock absorber
1. Install:
9Dust seal 1
9O-ring 2
9Collar 3
NOTE:
9Apply the molybdenum disulfide grease on the
bearing.
9Apply the lithium soap base grease on the dust
seals, O-rings and collars.
2. Install:
9Bush 1
9Collar 2
9Dust seal 3
NOTE:
9Apply the molybdenum disulfide grease on the
bearing.
9Apply the lithium soap base grease on the
bush, collars and dust seals.
9Install the dust seals with their lips facing out-
ward.
3. Adjust:
9Spring length (installed) a
*For EUROPE
NOTE:
The length of the spring (installed) changes 1.5
mm (0.06 in) per turn of the adjuster.
cC
Never attempt to turn the adjuster beyond
the maximum or minimum setting.
4. Tighten:
9Locknut 1
Spring length (installed) a
a
:
Standard
length
245 mm (9.65 in)
*268 mm (10.55 in)Extent of
adjustment
240.5~258.5 mm
(9.47~10.18 in)
*255.5~273.5 mm
(10.06~10.77 in)
5XF-9-30-5D 5/6/03 6:37 PM Page 26

6-3
SYSTEME D’ALLUMAGE
ZÜNDANLAGE
SISTEMA DI ACCENSIONEELEC
TEST DER ZÜNDFUNKENSTRECKE
1. Den Zündkerzenstecker von der
Zündkerze abtrennen.
2. Den dynamischen Zündfunken-
prüfer 1(Zündungs-Prüfgerät
2) gemäß Abbildung ansch-
ließen.
9Zündkerzenstecker 3
9Zündkerze 4
AFür USA und CDN
BAußer USA und CDN
3. Den Motor mit Hilfe des Kickstar-
ters durchdrehen.
4. Die Zündfunkenstrecke kontrollie-
ren.
5. Den Motor anlassen und die
Zündfunkenstrecke vergrößern,
bis es zu Fehlzündungen kommt.
(nur für USA und CDN)
INSPEKTION DES ANSCHLUSSES
DER KUPPLUNGEN UND KABEL
1. Kontrollieren:
9Anschluß deren Kupplungen
und Kabel
Rost/Staub/Lockerheit/Kurz-
schlußReparieren oder
erneuern.
INSPEKTION DES MOTORSTOPP-
KNOPFES „ENGINE STOP“
1. Prüfen:
9Kontakt des Motorstoppknop-
fes „ENGINE STOP“
Kein Stromdurchgang, wenn gedrückt
Erneuern.
Stromdurchgang, wenn freigelassen
Erneuern.ESSAI DE L’INTERVALLE
D’ETINCELLEMENT
D’ ALLUMAGE
1. Déconnecter le capuchon de bou-
gie de la bougie.
2. Connecter le testeur dynamique
d’étincelle 1(testeur d’allumage
2) comme indiqué.
9Capuchon de bougie 3
9Bougie 4
A Pour USA et CDN
BExcepté pour USA et CDN
3. Actionner la pédale de kick.
4. Contrôler l’écartement d’étincelle
d’allumage.
5. Démarrer le moteur et augmenter
l’intervalle d’étincellement jusqu’à
ce qu’un raté se produise. (unique-
ment USA et CDN)
VERIFICATION DE CONNEXION
DES COUPLEURS ET FILS
1. Contrôler:
9Connexion des coupleurs et fils
Rouille/poussière/desserré/court
-circuit

Réparer ou changer.
VERIFICATION DU BOUTON
D’ARRET DU MOTEUR “ENGINE
STOP”.
1. Examiner:
9Conductibilité du bouton d’arrêt
du moteur “ENGINE STOP”
Pas de continuité lorsqu’enfoncé 
Changer.
Continuité lorsque relâché  Changer.
IC622001
TEST DELLA DISTANZA TRA
GLI ELETTRODI
1. Scollegare la calotta della candela
dalla candela.
2. Collegare il tester dinamico delle
scintille 1(apparecchio per il
controllo dell’accensione 2) come
illustrato.
9Calotta della candela 3
9Candela 4
APer USA e CDN
BTranne che per USA e CDN
3. Azionare la pedivella della messa
in moto.
4. Controllare la distanza tra gli elet-
trodi dell’accensione.
5. Avviare il motore e aumentare la
distanza tra gli elettrodi finché non
si verifica uno scatto a vuoto. (sol-
tanto per USA e CDN)
IC624000
ISPEZIONE DEL
COLLEGAMENTO DI
ACCOPPIATORI E CONDUTTORI
1. Controllare:
9Collegamento di accoppiatori e
conduttori
Ruggine/Polvere/Allentamen-
to/Cortocircuito Ripararli o
sostituirli.
IC625002
ISPEZIONE DEL PULSANTE
“ARRESTO MOTORE”
1. Ispezionare:
9Comportamento del pulsante
“ARRESTO MOTORE”
Assenza di continuità mentre è premuto
Sostituirlo.
Continuità mentre viene rilasciato 
Sostituirlo.B/W B
Posizione12del seletto
re del tester
PREM-
11UTO
RILAS-Ω× 1
CIATO
Conduttore (+) del tester 
Conduttore Nero/Bianco 1
Conduttore (–) del tester 
Conduttore Nero 2
Distanza minima tra gli
elettrodi:
6,0 mm (0,24 in)
Ecartement d’étincelle
minimum:
6,0 mm (0,24 in)
Fil (+) de testeur 
Fil noir/blanc 1
Fil (–) de testeur 
Fil noir 2
B/W BPosition de12sélecteur du
testeur
ENFO-
11NCE
RELA-Ω× 1
CHE
Min. Zündfunkenstrecke:
6,0 mm (0,24 in)
Positives (+) Kabel des Prüfgerätes
Schwarz/Weiß Kabel 1
Negatives (–) Kabel des Prüfgerätes
Schwarz Kabel 2
B/W BPosition des12Wahlschaltersam Prüfgerät
GEDR-11ÜCKT
FREIGE-Ω× 1
LASSEN
5XF-9-30-6 4/21/03 2:13 PM Page 9