KINROAD 150 SERVICE MANUAL VERSION 1, DEC., 2005
27
After tapping the valve guide, you need to trim it with a reamer.
Clean the cylinder head and eliminate the scraps generated while
reaming.
VALVE SEAT
The relative position between the valve seat and the working surface of the valve is very important for the
valve to seal properly.
VALVE SEAT WIDTH MEASUREMENT
Clean the carbon accumulation in the combustion chamber.
Measure the width of the valve seat with a vernier caliper.
Standard 1.0mm
Service limit
1.8mm
When abrasion causes the valve seat width uneven, too wide or too narrow, it
will result in bad contact between the valve and the valve seat, and cannot seal
tight. At this time it must be reamed with a customized valve seat-grinding
cutter.
The valve seat-grinding cutter is the customized trimming tool for the valve seat,
and it has three cutting angles: 32
o
, 45
o
, and 60
o
.
While trimming, press the valve seat-grinding cutter to make rotary motion with
40 - 50N force.
VALVE SEAT FINISHING
Ream out the defects on the working surface with a 45
o
coarse
tooth grinding cutter.
z
The reamer can only be turned right; do not push
in or out directly
z
Some oil must be applied on the valve seat-grinding cutter to eliminate scraps when trimming.
z
Do not ream too much.