Checking The Valve Springs - Yamaha XG250 Service Manual

h. Install the valve into the cylinder head.
i. Press the valve through the valve guide and
onto the valve seat to make a clear impres-
sion.
j. Measure the valve seat width "c" again. If the
valve seat width is out of specification, reface
and lap the valve seat.
c
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
EAS24310

CHECKING THE VALVE SPRINGS

The following procedure applies to all of the
valve springs.
1. Measure:
Valve spring free length "a"
●
Out of specification → Replace the valve
spring.
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)
2. Measure:
Compressed valve spring force "a"
●
VALVES AND VALVE SPRINGS
Out of specification → Replace the valve
spring.
a. Compressed valve spring force
b. Installed length
Inner spring
Installed compression spring force
(intake)
75.00–91.70 N (16.86–20.61 lb)
(7.65–9.35 kgf)
Installed compression spring force
(exhaust)
75.00–91.70 N (16.86–20.61 lb)
(7.65–9.35 kgf)
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 (28.89–35.50 lb)
(13.10–16.10 kgf)
Installed compression spring force
(exhaust)
128.50–157.90 N (28.89–35.50 lb)
(13.10–16.10 kgf)
Installed length (intake)
32.00 mm (1.26 in)
Installed length (exhaust)
32.00 mm (1.26 in)
3. Measure:
Valve spring tilt "a"
●
Out of specification → Replace the valve
spring.
5-22
b
a