2006-2009 Honda TRX250EX/TRX250X Service Manual, Page 134Get this manual
CYLINDER HEADIVALVECAMSHAFT 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 clock-
wiseTOOL: Va lve guide ream er, 5.5 mm
079842000001 or
079842000000 !U.S.A.onlyl
Measure each valve guide 1.0and record it
SERVICE LIMIT: IN EX: 5.52 mm 10.217 in )
Subtract each valve stem 0.0from the corresponding guide 1.0to obtain the stem-ta-guide clearance
SERVICE LIMITS: IN: 0.12 mm (0.005 in) EX: 0.14 mm (0 .006 in)
Inspect and (eface the valve sealS whenever the valve gUides are replCced (page 815)
If the stem-ta-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-Io-guide clearance exceeds the service limit with new guide, also replace the valve