Valve Guide Replacement - Honda 2000 XR50R Service Manual

CYLINDER HEAD/V ALVES
Ream the guides to remove any carbon deposits
before measuring the guide.
Insert the reamer from the combustion chamber
side of the head and always rotate the reamer
clockwise.
TOOL:
Valve guide reamer, 5.0 mm 07984 - MA60001or
07984-MA60aOC
(U.S.A. only)
Measure and record each valve guide 1.0.
SERVICE LIMIT: IN/EX: 5.03 mm
(0.198
in)
Subtract each valve stem 0.0. from the correspond-
ing guide 1.0. to obtain the stem-te-guide clearance.
SERVICE LIMITS:
IN: 0.08 mm (0.003 in)
EX: 0.10 mrn (0.004 in)
Reface the ve/V9
If the stem-te-guide clearance is out of specification,
seats whenever detemermine if a new guide with standard dimen-
the valve guides
siens would bring the clearance within tolerance. If
are rep/aced
so, replace any guides as necessary and ream to fit.
(page
'-9). If the stem-to-guide clearance is out of specification
with a new guide, also replace the valve.
7-8
VALVE GUIDE REPLACEMENT
Chill new valve guides in the freezer section of a
refrigerator for about an hour.
Heat the cylinder head to 212 - 30rF (100 - 150°C)
with a hot plate or oven.
To avoid burns, wear heavy gloves whtm handling
the heated cylinder head.
CAUTION:
Do not use
a
torch to heat the cylinder head; it may
cause warping.
Support the cylinder head and drive out the valve
guides out of the cylinder head from the
combustion chamber side.
TOOL:
Valve guide driller, 5.0 mm 07942- MA60000
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GUIDE DRIVER
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