Yamaha YZ450F 2008 Manuel D'atelier Du Proprietaire page 104

REMOVING THE BALANCER
1. Straighten the lock washer tab.
2. Loosen:
• Nut (balancer) "1"
• Nut (primary drive gear) "2"
• Nut (balancer shaft driven gear)
"3"
Place an aluminum plate "a" between
the teeth of the balancer shaft drive
gear "4" and driven gear "5".
CHECKING THE 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.
CHECKING THE BALANCER
1. Inspect:
• Balancer
→
Cracks/damage Replace.
INSTALLING THE BALANCER
1. Install:
• Balancer shaft driven gear "1"
Install the balancer shaft driven gear
and balancer shaft with their lower
splines "a" aligning with each other.
2. Install:
• Balancer shaft driven gear "1"
• Align the punched mark "a" on the
balancer shaft drive gear with the
punched mark "b" on the balancer
shaft driven gear.
• Install the balancer shaft driven
gear and crankshaft with the lower
splines "c" aligning with each other.
3. Install:
• Lock washer "1"
• Nut (balancer shaft driven gear)
"2"
Nut (balancer shaft driv-
en gear):
50 Nm (5.0 m•kg, 36
ft•lb)
• Primary drive gear "3"
• Conical washer "4"
• Nut (primary drive gear) "5"
Nut (primary drive gear):
110 Nm (11.0 m•kg, 80
ft•lb)
• Straight key "6"
• Balancer "7"
• Lock washer "8"
4-38
BALANCER
• Nut (balancer) "9"
Nut (balancer):
45 Nm (4.5 m•kg, 33
ft•lb)
• Apply engine oil to the contact sur-
face and threaded portion of the nut
(primary drive gear).
• Place an aluminum plate "a" be-
tween the teeth of the balancer
shaft drive gear "10" and balancer
shaft driven gear "11".
• Install the conical washer with its
convex surface "b" outward.
4. Bend the lock washer tab.