2005-2006 Honda ATV TRX500FE/FM/TM FourTrax Foreman Factory Service Manual, Page 137Get this manual
CYLINDER HEADVALVE Check the cylinder head for warpage with straight edge and feeler gauge across the stud holesSERVICE LIMIT: 0.10 mm (0.004 in)
VALVE SPRING Check the valve springs for fatigue or damageMeasure the valve spring free lengthSERVICE LIMITS: Inner: 42.08 mm (1.657 in) Outer: 12.76 mm (1.683 in)