DAELIM VJF125 Service Manual - page 144
10-6
CYLINDER HEAD / VALVES
INTERVAL BETWEEN VALVE STEM AND VALVE GUIDE
Inspect each valve for bending, burning, scratches or
abnormal wear.
Insert the valves in their original positions in the valve
guid and check each valve moves up and down smothly,
without binding.
Measure and record the valve stem outer diameter in
three places along the valve guide sliding area.
SERVICE LIMIT : IN : 4.925 mm
EX: 4.905 mm
Replace the valve with a new one if the service limit is
exceeded.
Insert the valve guide reamer from the combustion
chamber side and ream the guide to remove any
carbon build-up before measuring the guide.
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 : 0.080 mm
EX: 0.100 mm
Measure the inner diameter of the new valve guide. If
the clearance is not within the service limit, replace the
valve.
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.
VALVE GUIDES REPLACEMENT
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.
Refinish the valve seats whenever the valve guides
are replaced to prevent uneven seating.