1999-2004 Honda TRX400EX FourTrax Service Manual, Page 96Get this manual
CYLINDER HEADlVALVE VALVE STEMlVALVE GUIDE Check that the valve moves smoothly in the guideCheck the valve for bending, burning or abnormal wearMeasure each valve stem O.Dand record itSERVICE LIMITS: IN: 5.46 mm (0.215 in) 5.44 mm 10.214 in)
Ream the valve guide to remove any carbon build-up before measuring the guideInsert the reamer from the combustion chamber side of the head and always rotate the reamer clockwiseTOOL Valve guide reamer, 5.5 mm
07984 2000001 or 07984200000D (U.S.Aonly)