Suzuki DF 2.5 Service Manual page 82

6-16 POWER UNIT
VALVE SPRING
Valve spring free length
Measure the valve spring free length.
 09900-20101: Vernier calipers
Valve spring free length:
Standard: IN. & EX. 22.42 mm (0.883 in)
Service limit: IN. & EX. 21.52 mm (0.847 in)
If the measurement exceeds the service limit, replace the valve
spring.
Valve spring preload
Measure the valve spring preload.
 09900-20101: Vernier calipers
Valve spring preload:
Standard:
IN. & EX. 36.5 – 41.9 N (3.65 – 4.19 kg, 8.05 – 9.24 lbs)
for 15 mm (0.6 in)
Service limit:
IN. & EX. 33 N (3.3 kg, 7.34 lbs)
for 15 mm (0.6 in)
If the measurement exceeds the service limit, replace the valve
spring.