Installing The Valves - Yamaha YFM250RX 2008 Service Manual

VALVES AND VALVE SPRINGS
3. Measure:
• Valve spring tilt
Out of specification → Replace the valve
spring.

INSTALLING THE VALVES

The following procedure applies to all of the
valves and related components.
1. Deburr:
• Valve stem end
(with an oil stone)
2. Lubricate:
• Valve stem
• Valve stem seal
(with the recommended lubricant)
3. Install:
• Valve spring seat
• Valve stem seal
• Valve
• Inner valve spring
• Outer valve spring
• Upper spring seat
(into the cylinder head)
NOTE: NOTE:
Install the valve springs with the larger pitch
facing up.
Larger pitch
Smaller pitch
4-29
ENG
Inner spring
Spring tilt (intake)
2.5°/1.60 mm (2.5°/0.063 in)
Spring tilt (exhaust)
2.5°/1.60 mm (2.5°/0.063 in)
Outer spring
Spring tilt (intake)
2.5°/1.60 mm (2.5°/0.063 in)
Spring tilt (exhaust)
2.5°/1.60 mm (2.5°/0.063 in)
Recommended lubricant
Molybdenum disulfide oil