Yamaha YZ450FX 2021 Owner's Service Manual page 248

4. Install:
• Lock washer "1"
New
• Balancer weight gear nut "2"
Balancer weight gear nut
50 N·m (5.0 kgf·m, 37 lb·ft)
• Primary drive gear "3"
• Conical washer "4"
New
• Primary drive gear nut "5"
Primary drive gear nut
80 N·m (8.0 kgf·m, 59 lb·ft)
• Straight key "6"
• Balancer "7"
• Lock washer "8"
New
• Balancer nut "9"
Balancer nut
45 N·m (4.5 kgf·m, 33 lb·ft)
TIP
• Apply engine oil to the contact surface and
threaded portion of the primary drive gear nut.
• Apply engine oil to the contact surfaces of the
conical washer.
• Place an aluminum plate "a" between the teeth
of the balancer drive gear "10" and balancer
weight gear "11".
• Install the conical washer with its convex sur-
face "b" outward.
4 4
5 5
5 5
4 4
10 10 10
3 3
11 11 11
1 1
2 2
a a
a a
11 11 11
3
b
E
5-62
5. Bend the lock washer tab.
OIL PUMP
9 9 9
8 8
7 7
6
6