Valve Guides Inspection; Valve Guides Replacement - DAELIM HISTORY 125 Service Manual

VALVE GUIDES
INSPECTION
● Insert the valve guide reamer from the combustion
chamber side and ream the guide to remove any carbon
build-up before measuring the guide.
NOTE
·Take care not to tilt or lean the reamer in the guide
while reaming.
Otherwise, the valve is installed slanted, that causes
oil leaks from the stem seal and improper valve seat
contact and results in the valve seat refacing not able
to be performed.
·Rotate the reamer clockwise, never counterclockwise
when inserting and removing.
TOOL : VALVE GUIDE REAMER
● Measure and record each valve guide inner diameter.
SERVICE LIMIT : 5.030 mm
● Measure the guide-to-stem clearance with a dial
indicator while rocking the stem in the direction of
normal thrust.
SERVICE LIMIT : IN : 0.090 mm
EX: 0.120 mm
● Measure the inner diameter of the new valve guide. If
the clearance is not within the service limit, replace the
valve.
REPLACEMENT
NOTE
·Refinish the valve seats whenever the valve guides
are replaced to prevent uneven seating.
● Heat the cylinder head to 130° C - 140° C (275° F - 290° F).
● 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.
CAUTION
·Using a torch to heat the cylinder head may cause
warping.
WARNING
·Wear insulated gloves to avoid burns when handling
the heated cylinder head.
CYLINDER HEAD / VALVES
VALVE GUIDE
REAMER
VALVE GUIDE
VALVE GUIDE
DRIVER
9-7