Yamaha YZ450FY 2009 Owner's Service Manual page 196

CHECKING THE BRAKE DISC
1. Measure:
• Brake disc deflection (only rear brake disc)
Use the dial gauge "1".
Out of specification → Inspect wheel runout.
If wheel runout is in good condition, replace
the brake disc.
Brake disc deflection limit:
Rear:
<Limit>: 0.15 mm (0.006 in)
2. Measure:
• Brake disc thickness "a"
Out of limit → Replace.
Brake disc thickness:
Front:
3.0 mm (0.12 in)
<Limit>: 2.5 mm (0.10 in)
Rear:
4.0 mm (0.16 in)
<Limit>: 3.5 mm (0.14 in)
INSTALLING THE FRONT WHEEL
1. Install:
• Bearing (left) "1"
• Spacer "2"
• Bearing (right) "3"
• Oil seal "4"
FRONT WHEEL AND REAR WHEEL
• Apply the lithium soap base grease on the
bearing and oil seal lip when installing.
• Use a socket that matches the outside diam-
eter of the race of the bearing.
• Left side of bearing shall be installed first.
• Install the oil seal with its manufacture's
marks or numbers facing outward.
Do not strike the inner race of the bearing.
Contact should be made only with the outer
race.
2. Install:
• Brake disc "1"
• Bolt (brake disc) "2"
Bolt (brake disc):
12 Nm (1.2 m•kg, 8.7 ft•lb)
Tighten the bolts in stage, using a crisscross
pattern.
5-5