Valve Spring Free Length and Preload

Referring to data, check that each spring is in good 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: 42.5 - 45.5 mm (1.6732 - 1.7913 in.) 

Limit: 42 mm (1.6535 in.) 

Valve spring preload 

Standard: 247 - 273 N (25.2 - 27.8 kgf) for 35 mm (55.5 - 61.4 lbf/1.378 in.) 

Limit: 240 N (24.5 kgf/54.0 lbf) for 35 mm (1.3780 in.) 

Fig 1: Checking Valve Spring Free Length

Courtesy of SUZUKI OF AMERICA CORP.