12.6 Valve Race Fixing and Adjustment 
Remove hackly and ragged parts on the valve race with a 
45°angled milling cutter.   
Note: 
Apply a layer of transparent or Prussian blue film onto the 
valve race so that it can be observed clearly. 
 
 
 
 
 
Remove 1/4 of external edge of valve race with a 32° angle 
milling cutter. 
 
 
 
 
 
 
 
 
Remove 1/4 of bottom of valve race with a 60° angle milling 
cutter. 
Remove the milling cutter and check the places processed. 
 
 
 
 
 
 
 
 
 
Grind and cut valve race with a 45°angle precise milling cutter 
till it gains a proper width. 
All the dents and ragged parts must be removed. 
 
Standard valve race width:    Intake: 1.0mm 
     Exhaust: 1.0mm 
 
 
 
 
Hackly part 
32° 
60° 
1mm 
45°