Honda XL125LK, Owner'S Manual

Page: 108 / 243

8-15
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CYLINDER HEAD/VALVES
VALVE GUIDE REPLACEMENT
Chill the replacement valve guides in the freezer
section of a refrigerator for about an hour.
Heat the cylinder head to 130°C – 140°C (275°F –
290°F) with a hot plate or oven. Do not heat the cylinder
head beyond 150°C (300°F). Use temperature indicator
sticks, available from welding supply stores, to be sure
the cylinder head is heated to the proper temperature.
Support the cylinder head and drive the valve guides
and clips out of the cylinder head from the combustion
chamber side.
While the cylinder head is still heated, take off the new
valve guides [1] from the freezer and install new clips
[2] to the new guides.
Drive new guides in the cylinder head from the
camshaft side.
Let the cylinder head cool to room temperature.
Take care not to tilt
or lean the reamer
in the guide while
reaming.
Use cutting oil on
the reamer during
this operation.
Ream the new valve guides.
Insert the reamer from the combustion chamber side of
the cylinder head and always rotate the reamer
clockwise.
Clean the cylinder head thoroughly to remove any
metal particles after reaming, and inspect and reface
the valve seats (page 8-16).
VALVE SEAT INSPECTION
Clean the intake and exhaust valves thoroughly to
remove the carbon deposits.
Apply light coating of Prussian Blue to the valve seats.
Tap the valve against the valve seat several times
without rotating the valve, using a rubber hose or other
hand lapping tool [1].
Wear insulated
gloves to avoid
burns when
handling the heated
cylinder head.
Using a torch to
heat the cylinder
head may cause
warping.
TOOL:
[1] Valve guide driver
07942-8920000
[1]
TOOL:
[3] Valve guide driver
07942-8920000
[2]
[3]
[1]
TOOL:
[1] Valve guide reamer
07984-MA60001
[1]
[1]