Suzuki DL650 Service Manual page 98

E N G I N E 3-47
VALVE STEM END CONDITION
Check the valve stem end face for pitting and wear.
VALVE SPRING
The force of the coil springs keeps the valve seat tight. Weak-
ened springs result in reduced engine power output, and often
account for the chattering noise coming from the valve mecha-
nism.
Check the valve springs for proper strength by measuring
their free length and also by the force required to compress
them. If the spring length is less than the service limit, or if the
force required to compress the spring does not fall within the
range specified, replace both the inner and outer springs as a
set.
Valve spring free length (IN & EX)
Service limit: INNER : 36.8 rnrn (1.45 in)
OUTER: 39.8
rnrn
(1.57 in)
Valve spring tension
Standard: (IN & EX) INNER : 4.2
-
4.8 kgfl29.9 rnrn
(9.26
-
10.58 lbs11.18 in)
OUTER: 17.0
-
19.6 kgf133.4 rnrn
(37.48
-
43.21 lbs11.31 in)
09900-201 02: Vernier calipers