Montesa COTA 300RR 2018, Owner'S Manual

Page: 92 / 176

Engine servicing
4-29 4-29
If the contact area is too high on the valve, the seat must
be lowered using a 32 ˚ flat cutter.
If the contact area is too lower on the valve, the seat
must be raised using a 60 ˚ interior cutter.
Valve Seat Refacing
Valve seat cutters.grinders or equivalent valve seat
refacing equipment are recommended to correct worn
valve seat.
Follow the refacing manufacturer’s instructions.

Contact area (too high or too low)
– Reface the valve seat.
The valves cannot be ground, If a valve face is burned
or badly worn or if it contacts the seat unevenly, replace
the valve.
(1) ROUGHNESS
60º
1
45º
32º
32º
60º