CF MOTO CF125T-19 2003, Service Manual

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8-14
CFMOTO
Replacement of valve guide
Caution
The valve works with valve guide as axis. Re-
placement of valve guide may cause poor sealing
between valve and valve seat. So the valve seat
should also be adjusted after replacement.
Heat up the cylinder head homogeneously to
100-150
℃
. Do not heat up part of the cylinder
head with gas nozzle to avoid distortion. Don ’ t
operate with undressed hand to avoid burn.
Drive the valve guide outward from one side of the
combustion chamber. Do not damage cylinder joint
face.
Drive new valve guide from one side of the cam-
shaft while the cylinder head still remains warm.
After the cylinder head is cooled, insert the
reamer from combustion chamber side, and ream
valve guide accurately.
Caution
l Insert reamer from the combustion
chamber.
l Do not deflect the reamer so as to avoid
leakage of valve stem sealing or devia-
tion from valve seat.
Wash clean the cylinder head, clean off the
scraps. Check and correct the contact surface of
valve seat.
Special tool:
Countersink: 152MI-236-022301-27
I
nspection and correction of
valve-seat ring
Inspection
Clean the carbon deposit on the valve.
Replace in case there are cracks or deflected
wear with valve surface.
Apply a thin layer of red lead oil to valve seat.
Keep valve still, and knock valve lightly with a
hammer to check the sealing condition.
Note
Valve can
’ t be corrected. When there are
cracks, damages or non-contacts with valve
seat, replace the valve.