Checking The Valve Lifters; Installing The Valves - Yamaha YZ 2017 Series Owner's Service Manual

3. Measure:
• Valve spring tilt "a"
Out of specification  Replace the valve
spring.
Spring tilt (intake)
1.7 mm (0.07 in)
Spring tilt (exhaust)
1.6 mm (0.06 in)

CHECKING THE VALVE LIFTERS

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1. Check:
• Valve lifter
Damage/scratches  Replace the valve lift-
ers and cylinder head.
EASB29B228

INSTALLING THE VALVES

1. Clean:
• Valve stem end
VALVES AND VALVE SPRINGS
2. Lubricate:
• Valve stem "1"
• Valve stem seal "2"
Recommended lubricant
Molybdenum disulfide oil
3. Install:
• Spring seat "1"
• Valve stem seal "2"
• Valve "3"
• Valve spring "4"
• Valve spring retainer "5"
(to the cylinder head)
TIP
• Make sure each valve is installed in its original
place.
• Install the valve springs with the larger pitch
"a" facing up.
b. Smaller pitch
4. Install:
• Valve cotter "1"
TIP
Install the valve cotters by compressing the
valve spring with the valve spring compressor
"2" and the valve spring compressor adapter
"3".
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