2003 Suzuki LT-Z400 Factory Service Manual, Page 67Get this manual
VALVE SPRING the valve seat tight weakThe force of the coil ened spring results in reduced engine power and accounts for the noise coming from the valve mechanismCheck the valve for proper strength by measuring their free length and also the force required to compress themIf the spring length is less than the service limit or if the force required to compress the valve is not within both the inner and outer as setValve spring freeEX) Service Limit: 38.8 mm (1.53 in) Valve spring tensionStandard: 182210 (18.621.4 kgf, 41.047.2 at length 31.5 mm (1.24