Yamaha YZ250F(E), Owner'S Service Manual

Page: 220 / 356

VALVES AND VALVE SPRINGS
5-27
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EAS1SM1223
CHECKING THE VALVE SPRINGS
1. Measure:
• Valve spring free length “a”
Out of specification

Replace the valve
spring.
2. Measure:
• Compressed valve spring force “a”
Out of specification

Replace the valve
spring.
3. Measure:
• Valve spring tilt “a”
Out of specification

Replace the valve
spring.
EAS1SM1224 CHECKING THE VALVE LIFTERS
1. Check:
• Valve lifter
Damage/scratches

Replace the valve lift-
ers and cylinder head.
EAS1SM1225
Free length (intake)
36.69 mm (1.44 in)
Limit
35.69 mm (1.41 in)
Free length (exhaust)
34.86 mm (1.37 in)
Limit
33.86 mm (1.33 in)
b. Installed length
Installed compression spring
force (intake)
146.00–168.00 N (14.89–17.13
kgf, 32.82–37.77 lbf)
Installed compression spring
force (exhaust)
137.00–157.00 N (13.97–16.01
kgf, 30.80–35.29 lbf)
Installed length (intake)
31.40 mm (1.24 in)
Installed length (exhaust)
28.50 mm (1.12 in)
Spring tilt (intake)
2.5 °/1.6 mm (2.5 °/0.06 in)
Spring tilt (exhaust)
2.5 °/1.5 mm (2.5 °/0.06 in)