25
Mill bottom belt ring area of valve seat by milling cutter of 60°
Make fine machining on working surface of valve
seat by milling cutter of
45° for its width reaching
correct data
Standard data of width of working
surface
：
1.0
～
1.2
。
Spread stamp-pad ink on valve seat, and embole
valve and turn, and remove valve for observe its
contact surface.
Caution; Good contact surface between valve
and its seat is important for sealing performance
of engine.
In case too high the contact surface, decrease its
height by milling cutter of
32°.
In case too low the contact surface, rise its height
by milling cutter of 60
°.
Finally mill by milling cutter of 45
° until the width
of contact surface of valve seat reached stipulated
data.
After valve seat finished machining, spread abradant
on valve seat, and then install valve and grind by
rubber tips with abradant. When grinding finished,
wash and clean up abradant remain on cylinder head
valve, valve seat and its guiding tube.