Yamaha YZ 2019 Series, Owner'S Service Manual

Page: 215 / 398

CAMSHAFT
5-16
EAM30084
CHECKING THE DECOMPRESSION SYSTEM
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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EAM30085
INSTALLING 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 ex-
haust camshaft sprocket and the alignment
mark “d” on the intake camshaft sprocket are
aligned with the edge of the cylinder head.
NOTICE
ECA24620
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 contact
surfaces.
•
Tighten the bolts to the specified torque in two
or three steps in the proper tightening se-
quence as shown.
NOTICE
ECA24630
The bolts (camshaft cap) must be tightened
evenly, or damage to the cylinder head, cam-
1 2
Bolt (camshaft cap)
10 N·m (1.0 kgf·m, 7.4 lb·ft)
a
b
d
c
3
T
R
.
.