1998-2001 Yamaha YFM600FHM Grizzly Factory Service Manual, Page 164Get this manual
VALVES AND VALVE SPRINGS
10.Measure: Valve spring free length Out of specification ReplaceFree length (valve spring): Inner: 40.1 mm(1.58 in) Limit: 38.1 mm (1.50 in) Outer: 43.8 mm (1.72 in) Limit: 41.6 mm (1.64 in) 11.Measure: Compressed spring force Out of specification Replace(Q) Installed length Compressed spring force: Inner: 7.3 8.9 kg at 31.2 mm (16.1 19.21b at 1.23 in) Outer: 15.2 18.6 kg at 34.2 mm (33.5 41.0 Ib at 1.35 in)