2006-2014 Honda FourTrax ATV TRX250 EX TRX250X Service Manual, Page 129Get this manual
CYLINDER HEADVALVECAMSHAFT Ream the guides 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 clockwise
TOOL: Valve guide reamer, 5.5 mm
07984-2000001 or 07984-2000000 (U.S.Aonly)
Measure each valve guide 1.0and record itSERVICE LIMIT: INEX: 5.52 mm (0.217 in) Subtract each valve stem 0.0from the corresponding guide I.Dto obtain the stem-to-guide clearance SERVICE LIMITS: IN: 0.12 mm (0.005 in) EX: 0.14 mm (0.006 in)
Inspect and reface the valve seats whenever the valve guides are replaced (page 8-15)
If the stem-to-guide clearance exceeds the service limit, determine if new guide with standard dimensions would bring the clearance within toleranceIf 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