Yamaha YZ450F(W), Owner'S Service Manual

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ENG
VALVES AND VALVE SPRINGS
ASSEMBLY AND INSTALLATION
1. Apply:
• Molybdenum disulfide oil
Onto the valve stem and valve stem seal.
2. Install:
• Valves
1
• Valve spring seats
2
• Valve stem seals
3
• Valve springs
4
• Valve spring retainers
5
NOTE:
• Make sure that each valve is installed in its
original place, also referring to the painted
color as follows.
Intake (middle)
a
: blue
Intake (right/left)
b
: gray
Exhaust: not paint
• Install the valve springs with the larger pitch
c
facing upward.
d
Smaller pitch
New
3. Install:
• Valve cotters
NOTE:
While compressing the valve spring with a
valve spring compressor
1
install the valve
cotters.
4. To secure the valve cotters onto the valve
stem, lightly tap the valve tip with a piece of
wood.
CAUTION:
Hitting the valve tip with excessive force
could damage the valve.
Valve spring compressor:
YM-4019/90890-04019