2005 YAMAHA YZ450F lock

4 - 50
ENGCLUTCH
EC493000
REMOVAL POINTS
EC483211
Clutch boss
1. Remove:
Nut 1
Lock washer 2
Clutch boss 3
NOTE:
Straighten the lock washer tab and use the
clutch holding tool 4 to hold the clutch boss.
ÈFor USA and CDN
ÉExcept for USA and CDN
Clutch holding tool:
YM-91042/90890-04086
È
É
EC494000
INSPECTION
EC484100
Clutch housing and boss
1. Inspect:
Clutch housing 1
Cracks/wear/damage → Replace.
Clutch boss 2
Scoring/wear/damage → Replace.
EC484201
Primary driven gear
1. Check:
Circumferential play
Free play exists → Replace.
Gear teeth
a
Wear/damage → Replace.
EC484400
Clutch spring
1. Measure:
Clutch spring free length
a
Out of specification → Replace springs
as a set.
Clutch spring free length:
Standard
47.8 mm (1.88 in) 46.8 mm (1.84 in)

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ENGCLUTCH
EC4A5000
ASSEMBLY AND INSTALLATION
Push lever
1. Install:
Push lever 1
Bolt (push lever)
NOTE:
Apply the lithium soap base grease on the oil
seal lip.
Apply the engine oil on the push lever.
Fit the seat plate 2 in the groove a of the
push lever and tighten the bolt (seat plate).
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:
Install the lock washer with its concaves fit-
ted over the convexes of the clutch boss.
Use the clutch holding tool 3 to hold the
clutch boss.
ÈFor USA and CDN
ÉExcept for USA and CDN
Clutch holding tool:
YM-91042/90890-04086
New
T R..75 Nm (7.5 m · kg, 54 ft · lb)
ÈÉ

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ENGCLUTCH
3. Bend the lock washer 1 tab.
4. Install:
Friction plate 1
Clutch plate 2
NOTE:
Install the clutch plates and friction plates
alternately on the clutch boss, starting with a
friction plate and ending with a friction plate.
Apply the engine oil on the friction plates and
clutch plates.
5. Install:
Bearing 1
Plain washer 2
Circlip 3
To push rod 1 4.
NOTE:
Apply the engine oil on the bearing and plain
washer.
New
6. Install:
Push rod 2 1
Ball 2
Push rod 1 3
NOTE:
Apply the engine oil on the push rod 1, 2 and
ball.

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ENGBALANCER
BALANCER
BALANCER
Extent of removal:
1 Balancer drive gear
2 Balancer
Extent of removal Order Part name Q’ty Remarks
BALANCER REMOVAL
Preparation for removal Clutch housing Refer to “CLUTCH” section.
Crankcase cover (right) Refer to “OIL FILTER, WATER PUMP AND
CRANKCASE COVER (RIGHT)” section.
Stator Refer to “CDI MAGNETO” section.
1 Nut (primary drive gear) 1
Refer to “REMOVAL POINTS”.
2 Nut (balancer) 1
3 Conical washer 1
4 Primary drive gear 1
5 Balancer drive gear 1
6 Lock washer 1
7 Balancer driven gear 1
8 Balancer 1 Refer to “REMOVAL POINTS”.
2
1
2

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ENGBALANCER
REMOVAL POINTS
Balancer drive gear and balancer driven
gear
1. Straighten the lock washer tab.
2. Loosen:
Nut (primary drive gear) 1
Nut (balancer) 2
NOTE:
Place an aluminum plate a between the teeth
of the balancer drive gear 3 and driven gear
4.
a 3
14
2
4 3
a
Balancer
1. Remove:
Balancer 1
NOTE:
When removing the balancer shaft, align the
center of the balancer shaft weight a along
the line connecting the centers of the crank-
shaft and balancer shaft.
INSPECTION
Primary drive gear, balancer drive gear and
balancer driven gear
1. Inspect:
Primary drive gear 1
Balancer drive gear 2
Balancer driven gear 3
Wear/damage → Replace.
Balancer
1. Inspect:
Balancer
Cracks/damage → Replace.

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ENG
DEMONTAGE-EINZELHEITEN
Ausgleichswellen-Antriebsritzel und -rad
1. Die Lasche der Sicherungsscheibe umbie-
gen.
2. Lockern:
Mutter (Primärantriebsritzel) 1
Ausgleichswellen-Mutter 2
HINWEIS:
Ein Alu-Blechstück a zwischen das Antriebs-
ritzel 3 und das Antriebsrad 4 klemmen.
Ausgleichswelle
1. Demontieren:
Ausgleichswelle 1
HINWEIS:
Zur Demontage der Ausgleichswelle die Mitte
a des Ausgleichsgewichts auf die Mitte der
Ausgleichs- und Kurbelwellen ausrichten.
KONTROLLE
Primärantriebsritzel, Ausgleichswellen-
Antriebsritzel und -rad
1. Kontrollieren:
Primärantriebsritzel 1
Ausgleichswellen-Antriebsritzel 2
Ausgleichswellen-Antriebsrad 3
Verschlissen/beschädigt → Erneuern.
Ausgleichswelle
1. Kontrollieren:
Ausgleichswelle
Rissig/beschädigt → Erneuern.
BALANCIER
AUSGLEICHSWELLE
POINTS DE DEPOSE
Pignon menant et pignon mené du balancier
1. Redresser l’onglet de la rondelle-frein.
2. Desserrer:
Ecrou (pignon menant de transmission pri-
maire) 1
Ecrou (balancier) 2
N.B.:
Placer une plaque d’aluminium a entre les dents
du pignon menant 3 et du pignon mené 4 du
balancier.
Balancier
1. Déposer:
Balancier 1
N.B.:
Pour déposer l’arbre de balancier, aligner le centre
a du contrepoids d’arbre de balancier sur la ligne
raccordant les centres du vilebrequin et de l’arbre
de balancier.
CONTROLE
Pignon menant de transmission primaire,
pignon menant et pignon mené du balancier
1. Contrôler:
Pignon menant de transmission primaire 1
Pignon menant du balancier 2
Pignon mené du balancier 3
Usure/endommagement → Remplacer.
Balancier
1. Contrôler:
Balancier
Craquelures/endommagement → Remplacer.

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ENGBALANCER
ASSEMBLY AND INSTALLATION
Balancer, balancer drive gear and balancer
driven gear
1. Install:
Balancer 1
NOTE:
When installing the balancer shaft, align the
center of the balancer shaft weight a along
the line connecting the centers of the crank-
shaft and balancer shaft.
2. Install:
Balancer driven gear 1
NOTE:
Install the balancer driven gear onto the bal-
ancer while aligning the punch mark a on the
balancer driven gear with the lower spline b
on the balancer end.
3. Install:
Balancer drive gear 1
NOTE:
Align the punched mark a on the balancer
drive gear with the punched mark b on the
balancer driven gear.
Align the punched mark c on the balancer
drive gear with the lower spline d on the
crankshaft.
4. Install:
Lock washer 1
Nut (balancer) 2
Primary drive gear 3
Conical washer 4
Nut (primary drive gear) 5
NOTE:
Apply engine oil to the contact surface and
threaded portion of the nut (primary drive
gear).
Place an aluminum plate a between the
teeth of the balancer drive gear 6 and driven
gear 7.
Install the primary drive gear with its weight
reduction holes b facing the engine.
Install the conical washer with its convex sur-
face c outward.
5. Bend the lock washer tab.
a 6
17
2
T R..50 Nm (5.0 m · kg, 36 ft · lb)
E
7
6a
c b
5
4
3
T R..110 Nm (11.0 m · kg, 80 ft · lb)

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ENGKICK AXLE AND SHIFT SHAFT
REMOVAL POINTS
EC4B3101
Kick axle assembly
1. Remove:
Kick axle 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
EC4C4200
Kick axle and ratchet wheel
1. Check:
Ratchet wheel 1 smooth movement
Unsmooth movement → Replace.
Kick axle 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.