Operation Manual

6. Cylinder Head / Valve
6-13
Use 60° cutter to cut a quarter lower parts out.
Remove the cutter and check new valve seat.
Use 45° cutter to grind the valve seat to specified
width.
Caution
z Make sure that all roughness and uneven
faces had been grinded.
Grind valve seat again if necessary.
Coat the valve seat surface with red paint.
Install the valve through valve guide until the valve
contacting with valve seat, slightly press down the
valve but do not rotate it so that a seal track will be
created on contact surface.
Caution
z The contact surfaces of valve and valve seat
are very important to the valve sealing
capacity.
If the contact surface is too high, grind the valve
seat with 32° cutter.
Then, grind the valve seat to specified width with
45° cutter.
If the contact surface is too low, grind the valve
seat with 60° cutter.
Then, grind the valve seat to specified width with
45° cutter.
Old valve seat width
60°
45°
1.0mm
Contact surface too high
32°
Old valve seat width
Contact surface too low
60°
Old valve seat width
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