2016 YAMAHA WR 450F torque

CAMSHAFT
6-16
EAS2GC1242CHECKING THE DECOMPRESSION SYS-
TEM
1. Check:• Decompression system
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a. Check that the decompressor cam “1”
moves smoothly.
b. Check that the decompressor lever pin “2” projects from the camshaft.
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EAS2GC1243INSTALLING THE CAMSHAFTS
1. Install:• Exhaust camshaft “1”
• Intake camshaft “2”
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a. Turn the crankshaft counterclockwise with a
wrench.
TIP
• Apply molybdenum disulfide oil to the cam-shafts.
• Apply the engine oil on the decompression
system.
b. Align the top dead center (TDC) mark “a” on the rotor with the alignment mark “b” on the
crankcase cover. c. Fit the timing chain “3” onto both camshaft
sprockets and install the camshafts on the
cylinder head.
TIP
Make sure that the alignment mark “c” on the
exhaust camshaft sprocket and the alignment
mark “d” on the intake camshaft sprocket are
aligned with the edge of the cylinder head.
ECA
NOTICE
Do not turn the crankshaft during the cam-
shaft installation. Damage or improper
valve timing will result.
d. Install the clips, the camshaft caps and the bolts (camshaft cap).
TIP
• Before installing the clips, cover the cylinder head with a clean cloth to prevent the clips
from coming off into the cylinder head cavity.
• Apply the engine oil to the threads and con- tact surfaces.
• Tighten the bolts to the specified torque in two or three steps in the proper tightening se-
quence as shown.
ECA
NOTICE
The bolts (camshaft cap) must be tightened
evenly, or damage to the cylinder head,
camshaft caps, and camshaft will result.
1
2
Bolt (camshaft cap)
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
ab
c
3
d
T R..

CYLINDER HEAD
6-21
EAS2GC1248INSTALLING THE CYLINDER HEAD
1. Install:• Timing chain guide (intake side) “1”
• Dowel pins “2”
• Cylinder head gasket
• Dowel head “4”
TIP
While pulling up the timing chain, install the tim-
ing chain guide (intake side) and the cylinder
head.
2. Install:• Washer “1”
• Cylinder head bolt “2”
• Engine ground sub-lead “3”
• Cylinder head bolt “4”
TIP
Tighten the bolts using the following procedure.
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a. Wash the threads and contact surfaces of the bolts, the contact surfaces of the wash-
ers, the contact surface of the cylinder head,
and the threads of the crankcase.
b. Apply molybdenum disulfide grease to the threads and contact surfaces of the bolts
and to both contact surfaces of the washers
“1”.
c. Install the washers and the bolts.
d. Tighten the bolts to the specified torque in
two or three steps in the proper tightening
sequence as shown. e. Remove the bolts.
f. Again apply molybdenum disulfide grease to
the threads and contact surfaces of the bolts
and to both contact surfaces of the washers.
g. Retighten the bolts.
TIP
Tighten the bolts to the specified torque in two
or three steps in the proper tightening se-
quence as shown.
h. Put a mark on the corner “1” of the bolt (cyl- inder head) and the cylinder head “2” as
shown.
New
1 2
2
4
3
1
3 4
2
2
4
Bolt “1”–“4”
1st
30 Nm (3.0 m·kgf, 22 ft·lbf)
Bolt “1”–“4” 2nd
20 Nm (2.0 m·kgf, 14 ft·lbf)
T R..
15
6
42
3
FWD
x2 x4
T R..
1
2

CYLINDER HEAD
6-22
i. Retighten the cylinder head mounting bolts
150° in the proper tightening sequence.
TIP
Tighten the bolts in two steps (90° and 60°) to
reach the specified angle in the proper tighten-
ing sequence.
j. Tighten the bolts to the specified torque.
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Bolt “1”–“4” Final
Specified angle 150°
Bolt “5”, “6” 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
T R..
T R..