2006 Honda TRX680 Rincon Factory Service Manual, Page 214Get this manual
CYLINDER HEADVALVECAMSHAFT Ream the valve guide to remove any carbon buildup before measuring the guideInsert the reamer from the combustion chamber side of the cylinder head and always rotate the reamer clockwiseTOOLS: Valve guide reamer, 5.5 mm 07984-2000001 or 07984-200000D (U.S.Aonly) REAMER
Measure each valve guide I.Dand record itSERVICE LIMIT: 5.53 mm (0.218 in) Subtract each valve stem O.Dfrom the corresponding guide I.Dto obtain the stem-to-guide clearanceSERVICE LIMITS: IN: 0.12 mm (0.005 in) EX: 0.14 mm (0.006 in) Inspect and reface If the stem-to-guide clearance exceeds the service the valve seats limit, determine if new guide with standard whenever the valve dimensions would bring the clearance within toler guides are replaced ance(page 9-13)If so, replace any guides as necessary and ream to fitIf the stem-to-guide clearance exceeds the service limit with new guide, also replace the valve
VALVE GUIDE REPLACEMENT
Mark new valve guides at the specified height indicated below, using markerChill the new valve guides in freezer for about an hourBe sure to wear heavy gloves to avoid burns when handling the heated cylinder headUsing torch to heat the cylinder head may cause warpage