lock YAMAHA YZ250F 2003 Service Manual

4 - 53
ENG

CLUTCH
EC4A5000
ASSEMBLY AND INSTALLATION
Push lever shaft
1. Install:

Push lever shaft
1


Bolt (push lever shaft)
2

NOTE:


Apply the lithium soap base grease on the oil
seal lip.

Apply the engine oil on the push lever shaft.

Fit the seat plate
3
in the groove
a
of the
push lever shaft and tighten the bolt (seat
plate).
3
1a2
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)

Clutch
1. Install:

Primary driven gear 1
Thrust washer 2
Clutch boss 3
NOTE:
Apply the engine oil on the primary driven gear
inner circumference.
2. Install:
Lock washer 1
Nut (clutch boss) 2
NOTE:
Use the clutch holding tool 3 to hold the clutch
boss.
ÅFor USA and CDN
ıExcept for USA and CDN
Clutch holding tool:
YM-91042/90890-04086
T R..60 Nm (6.0 m · kg, 43 ft · lb)
Å
ı

4 - 54
ENG
3. Bend the lock washer 1 tab.
4. Install:
Seat plate 1
Cushion spring 2
NOTE:
Install the seat plate with its chamfered por-
tion a facing the clutch boss 3.
Install the seat plate so that it is not caught
on the step b.
Install the cushion spring with the paint c
facing out.
1
2
c
3
a
b
5. Install:
Friction plate 1 1
Clutch plate 1 2
Friction plate 2 3
Clutch plate 2 4
NOTE:
Install the clutch plates and friction plates
alternately on the clutch boss, starting with a
friction plate and ending with a friction plate.
Use the friction plates 1 for the first and final
while paying attention to the difference in
surface pattern.
Apply the engine oil on the friction plates and
clutch plates.
Unlike the clutch plate 2, the clutch plate 1
has no surface gloss. Use the clutch plate 1
for the first while paying attention to the dif-
ference in surface gloss.
6. Install:
Bearing 1
Washer 2
Circlip 3
To push rod 1 4.
NOTE:
Apply the engine oil on the bearing and
washer.
CLUTCH

4 - 63
ENGBALANCER
BALANCER
Extent of removal:1 Balancer shaft drive gear2 Balancer shaft
Extent of removal Order Part name Q’ty Remarks
BALANCER REMOVAL
Preparation for removal Primary driven gear Refer to “CLUTCH” section.
Right crankcase cover Refer to “OIL FILTER ELEMENT,
WATER PUMP AND RIGHT CRANK-
CASE COVER” section.
Stator Refer to “CDI MAGNETO” section.
1 Nut (primary drive gear) 1
Refer to “REMOVAL POINTS”.
2 Nut (balancer shaft driven gear) 1
3 Lock washer 1
4 Primary drive gear 1
5 Balancer shaft drive gear 1
6 Lock washer 1
7 Balancer shaft driven gear 1
8 Balancer shaft 1 Refer to “REMOVAL POINTS”.
2
1
2

4 - 64
ENGBALANCER
REMOVAL POINTS
Balancer shaft drive gear and balancer
shaft driven gear
1. Straighten the lock washer tab.
2. Loosen:
Nut (primary drive gear) 1
Nut (balancer shaft driven gear) 2
NOTE:
Place an aluminum plate a between the teeth
of the balancer shaft drive gear 3 and driven
gear 4.
Balancer shaft
1. Remove:
Balancer shaft 1
NOTE:
When removing the balancer shaft, align the
center a of the balancer shaft weight along
the line connecting the centers of the crank-
shaft and balancer shaft.
INSPECTION
Primary drive gear, balancer shaft drive
gear and balancer shaft driven gear
1. Inspect:
Primary drive gear 1
Balancer shaft drive gear 2
Balancer shaft driven gear 3
Wear/damage → Replace.
Balancer shaft
1. Inspect:
Balancer shaft
Cracks/damage → Replace.

ENG
4 - 64
BALANCIER
AUSGLEICHSWELLE
BILANCIERE
AUSBAU
Ausgleichswellen-Antriebs- und -
Abtriebsräder
1. Die Lasche der Sicherungs-
scheibe umbiegen.
2. Lockern:
Mutter (Primärantriebsrad)
1
Mutter (Ausgleichswelle) 2
HINWEIS:
Ein Stückchen Aluminium a zwi-
schen die Zähne des Ausgleichswel-
len-Antriebsrades 3 und Aus-
gleichswellen-Abtriebrades 4 legen.
Ausgleichswelle
1. Demontieren:
Ausgleichswelle 1
HINWEIS:
Beim Ausbau der Ausgleichswelle
muß sich das Ausgleichsgewicht mit-
tig a auf der Fluchtlinie zwischen
den Mittelpunkten der Nockenwellen-
und Ausgleichswellen-Enden befin-
den.
PRÜFUNG
Primär- und Ausgleichswellen-
Antriebs- und -Abtriebsräder
1. Kontrollieren:
Primärantriebsrad 1
Ausgleichswellen-Antriebs-
rad 2
Ausgleichswellen-Abtriebs-
rad 3
Verschleiß/Beschädigung →
Erneuern.
Ausgleichswelle
1. Kontrollieren:
Ausgleichswelle
Rißbildung/Beschädigung
→ Erneuern. POINTS DE DEPOSE
Pignon menant et pignon mené du
balancier
1. Redresser l’ongle de rondelle
d’arrêt.
2. Desserrer:
Ecrou (pignon menant pri-
maire) 1
Ecrou (pignon mené de balan-
cier) 2
N.B.:
Placer une plaquette en aluminium a
entre les dents du pignon menant 3 et le
pignon mené 4 du balancier.
Balancier
1. Déposer:
Balancier 1
N.B.:
Avant de déposer l’arbre de balancier,
aligner le centre a du poids de l’arbre
de balancier avec la ligne reliant le cen-
tre du vilebrequin et le centre de l’arbre
de balancier.
CONTROLE
Pignon menant primaire, pignon
menant et pignon mené du balancier
1. Contrôler:
Pignon menant primaire 1
Pignon menant du balancier 2
Pignon mené du balancier 3
Usure/endommagements →
Remplacer.
Balancier
1. Contrôler:
Balancier
Craquelures/endommagement
→ Remplacer.PUNTI DI RIMOZIONE
Ingranaggio conduttore dell’albero di
equilibratura e ingranaggio condotto
dell’albero di equilibratura
1. Spianare la linguetta della ron-
della di bloccaggio.
2. Allentare:
Dado (ingranaggio conduttore
della trasmissione primaria) 1
Dado (Ingranaggio condotto
dell’albero di equilibratura) 2
NOTA:
Inserire una piastra di alluminio a tra i
denti dell’ingranaggio conduttore 3 e
l’ingranaggio condotto 4 dell’albero di
equilibratura.
Albero di equilibratura
1. Rimuovere:
Albero di equilibratura 1
NOTA:
Nel rimuovere l’albero di equilibratura,
allineare il centro del peso dell’albero di
equilibratura a lungo la linea che col-
lega i punti centrali dell’albero motore e
dell’albero di equilibratura.
ISPEZIONE
Ingranaggio conduttore della trasmis-
sione primaria, ingranaggio condut-
tore dell’albero di equilibratura e
ingranaggio condotto dell’albero di
equilibratura
1. Ispezionare:
Ingranaggio conduttore della
trasmissione primaria 1
Ingranaggio conduttore
dell’albero di equilibratura 2
Ingranaggio condotto
dell’albero di equilibratura 3
Usura/danno → Sostituire.
Albero di equilibratura
1. Ispezionare:
Albero di equilibratura
Incrinature/danno → Sostitu-
ire.

4 - 65
ENGBALANCER
ASSEMBLY AND INSTALLATION
Balancer shaft, balancer shaft drive gear
and balancer shaft driven gear
1. Install:
Balancer shaft 1
NOTE:
Apply the engine oil on the bearing.
When installing the balancer shaft, align the
center a of the balancer shaft weight along
the line connecting the centers of the crank-
shaft and balancer shaft.
2. Install:
Balancer shaft driven gear 1
NOTE:
Install the balancer shaft driven gear onto the
balancer shaft while aligning the punch mark
a on the balancer shaft driven gear with the
lower spline b on the balancer shaft end.
3. Install:
Balancer shaft drive gear 1
NOTE:
Align the punched mark a on the balancer
shaft drive gear with the punched mark b on
the balancer shaft driven gear 2.
Align the punched mark c on the balancer
shaft drive gear with the lower spline d on
the crankshaft end.
4. Install:
Lock washer 1
Nut (balancer shaft driven gear) 2
Primary drive gear 3
Nut (primary drive gear) 4
NOTE:
Install the primary drive gear with its stepped
side a facing the engine.
Place an aluminum plate b between the
teeth of the balancer shaft drive gear 5 and
driven gear 6.
5. Bend the lock washer tab.
T R..50 Nm (5.0 m · kg, 36 ft · lb)
T R..75 Nm (7.5 m · kg, 54 ft · lb)

4 - 73
ENGKICK SHAFT AND SHIFT SHAFT
REMOVAL POINTS
Kick shaft assembly
1. Remove:
Kick shaft assembly 1
NOTE:
Unhook the torsion spring 2 from the hole a
in the crankcase.
EC4C3101
Shift guide and shift lever assembly
1. Remove:
Bolt (shift guide)
Shift guide 1
Shift lever assembly 2
NOTE:
The shift lever assembly is disassembled at
the same time as the shift guide.
EC4N3100
Segment
1. Remove:
Bolt (segment) 1
Segment 2
NOTE:
Turn the segment counterclockwise until it
stops and loosen the bolt.
INSPECTION
Kick shaft and ratchet wheel
1. Check:
Ratchet wheel 1 smooth movement
Unsmooth movement → Replace.
Kick shaft 2
Wear/damage → Replace.
Spring 3
Broken → Replace.
EC4C4300
Kick gear, kick idle gear and ratchet wheel
1. Inspect:
Kick gear 1
Kick idle gear 2
Ratchet wheel 3
Gear teeth a
Ratchet teeth b
Wear/damage → Replace.

4 - 77
ENGKICK SHAFT AND SHIFT SHAFT
3. Install:
Spring guide 1
NOTE:
Slide the spring guide into the kick shaft, make
sure the groove a in the spring guide fits on
the stopper of the torsion spring.
4. Install:
Kick shaft assembly 1
Washer 2
NOTE:
Apply the molybdenum disulfide grease on
the contacting surfaces of the kick shaft stop-
per a and stopper plate 3.
Apply the engine oil on the kick shaft.
Slide the kick shaft assembly into the crank-
case and make sure the kick shaft stopper a
fits into the stopper plate.
5. Hook:
Torsion spring 1
NOTE:
Turn the torsion spring clockwise and hook
into the proper hole a in the crankcase.
Kick idle gear
1. Install:
Kick idle gear 1
Washer 2
Circlip 3
NOTE:
Apply the engine oil on the kick idle gear
inner circumference.
Install the kick idle gear with its depressed
side a toward you.

4 - 79
ENGCDI MAGNETO
EC4L3000
REMOVAL POINTS
Rotor
1. Remove:
Nut (rotor) 1
Washer 2
Use the rotor holding tool 3.
2. Remove:
Rotor 1
Use the flywheel puller 2.
NOTE:
When installing the flywheel puller, turn it
counterclockwise.
Rotor holding tool:
YU-1235/90890-01235
Flywheel puller:
YM-1189/90890-01189
EC4L4000
INSPECTION
EC4L4101
CDI magneto
1. Inspect:
Rotor inner surface a
Stator outer surface b
Damage → Inspect the crankshaft
runout and crankshaft bearing.
If necessary, replace CDI magneto and/
or stator.
EC4L4200
Woodruff key
1. Inspect:
Woodruff key 1
Damage → Replace.

4 - 83
ENGENGINE REMOVAL
Extent of removal:1 Engine removal
Extent of removal Order Part name Q’ty Remarks
Ignition coil
Disconnect the CDI magneto lead.
Right engine guard
1 Lower engine guard 1
2 Neutral switch 1
3 Bolt (oil hose) 2
4 Drive chain sprocket cover 1
5 Nut (drive sprocket) 1
Refer to “REMOVAL POINTS”. 6 Lock washer 1
7 Drive sprocket 1
8 Clip 1
9 Bolt (brake pedal) 1
10 Brake pedal 1
11 Upper engine bracket 2
12 Lower engine bracket 2
13 Engine mounting bolt 3
14 Pivot shaft 1
Refer to “REMOVAL POINTS”.
15 Engine 1
1