Checking The Valve Springs - Yamaha YFM250RX 2008 Service Manual

VALVES AND VALVE SPRINGS

CHECKING THE VALVE SPRINGS

The following procedure applies to all of the
valve springs.
1. Measure:
• Valve spring free length
Out of specification → Replace the valve
spring.
2. Measure:
• Compressed valve spring force
Out of specification → Replace the valve
spring.
Compressed valve spring force
Installed length
4-28
ENG
Inner spring
Free length (intake)
36.17 mm (1.42 in)
Free length (exhaust)
36.17 mm (1.42 in)
Outer spring
Free length (intake)
36.63 mm (1.44 in)
Free length (exhaust)
36.63 mm (1.44 in)
Inner spring
Installed compression spring
force (intake)
75.00 ~ 91.70 N (7.65 ~
9.35 kg) (16.86 ~ 20.62 lb)
Installed compression spring
force (exhaust)
75.00 ~ 91.70 N (7.65 ~
9.35 kg) (16.86 ~ 20.62 lb)
Installed length (intake)
30.50 mm (1.20 in)
Installed length (exhaust)
30.50 mm (1.20 in)
Outer spring
Installed compression spring
force (intake)
128.50 ~ 157.90 N (13.10 ~
16.10 kg) (28.89 ~ 35.50 lb)
Installed compression spring
force (exhaust)
128.50 ~ 157.90 N (13.10 ~
16.10 kg) (28.89 ~ 35.50 lb)
Installed length (intake)
32.00 mm (1.26 in)
Installed length (exhaust)
32.00 mm (1.26 in)