SANYANG INDUSTRY CO. XS125-K Service Manual page 48

5.INSPECTION/ADJUSTMENT
If the contact area is too high on the valve,the seat
must be lowered using a 37.5 degree cutter, then
finish with a 45 degree cutter.
If the contact area is too low on the valve,the seat
must be raised using a 63.5 degree cutter, then finish
with a 45 degree cutter.
After cutting the seat, apply lapping compound to the
valve face, and lap the valve using light pressure.
5-12
CONTACT AREA
TOO HIGH
CONTACT AREA TOO LOW
CUT BOTTOM END
CUT TOP END
o
63.5