Valve Spring Free Length and Preload
Referring to data, check to be sure that each spring is in sound condition, free of any evidence of breakage or weakening. Remember, weakened valve springs can cause chatter, not to mention possibility of reducing power output due to gas leakage caused by decreased seating pressure.
Valve spring free length
Standard: 51.13 mm (2.013 in.)
Limit: 50.13 mm (1.974 in.)
Valve spring preload
Standard: 209 - 241 N (20.9 - 24.1 kgf) for 37.60 mm (46.1 - 53.1 lb/1.480 in.)
Limit: 208 N (20.8 kgf) for 37.60 mm (45.9 lb/1.480 in.)