Yamaha YZ450FA 2011 Owner's Service Manual page 133

a. Wash the threads and contact surfaces of
the bolts, the contact surfaces of the plain
washers, the contact surface of the cylinder
head, and the threads of the crankcase.
b. Apply the molybdenum disulfide grease on
the threads and contact surfaces of the bolts
and on both contact surfaces of the plain
washers.
c. Install the plain washers and bolts.
d. Tighten the bolts to the specified torque in
two or three steps in the proper tightening
sequence as shown.
Bolts (cylinder head):
1st:
30 Nm (3.0 m•kg, 22 ft•lb)
e. Remove the bolts.
f. Again apply the molybdenum disulfide
grease on the threads and contact surfaces
of the bolts and on both contact surfaces of
the plain washers.
g. Retighten the bolts.
Tighten the bolts to the specified torque in two
or three steps in the proper tightening se-
quence as shown.
Bolts (cylinder head):
2nd:
20 Nm (2.0 m•kg, 14 ft•lb)
h. Put a mark on the corner "1" of the bolt (cyl-
inder head) and the cylinder head "2" as
shown.
Tighten the bolts two times at specified angles
of 90°and 60° to reach the specified angle of
150° in the proper tightening sequence as
shown.
Bolts (cylinder head):
Final:
Specified angle 150°
3. Install:
• Bolt (cylinder head) "1"
Bolt (cylinder head):
10 Nm (1.0 m•kg, 7.2 ft•lb)
4-22
CYLINDER HEAD