Hisun HS500ATV-2 Maintenance Manual page 26

Measure the width of mating surfaces of valve
1.5mm repairing limit value: 1.5mm
If the valve seat is to wide or narrow or cracked,
grind it to ensure impermeability.
Measure bore diameter of valve guide with internal
micrometer and special gauge. At last calculate clearance
between valve stem and valve guide.
Repairing limit value: intake : 0.12mm exhaust: 0.14mm
Note :eliminate carbon in the pipe before measuring.
If the pipe will be replaced, grind the valve seat again
5、Check whether the valve is bent, burn or the valve stem
is worn out
Check the motion of valve and measure external diameter.
Repairing limit value: intake: 6.92mm exhaust: 6.9mm. See
figure 2-22.
Figure 2-21-3
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