Montesa COTA 301RR 2023, Owner'S Manual

Page: 94 / 180

Engine servicing
4-31 4-31
(1) SPRING SEAT
(2) STEM SEAL
(3) VALVE
(4) INNER SPRING
(5) OUTER SPRING
(6) RETAINER
(7) COTTERS
Cylinder Head Assembly
Blow out all oil passages in the cylinder head with
compressed air.
Install the spring seat and new stem seal.
Lubricate the valve stem sliding surface with molybdenum
solution.
Insert the valves into the guide while turning it slowly to
avoid damage to the stem seal.
Using a 45 ˚ seat cutter, cut the seat to proper width.
Make sure all pitting and irregularities are removed.
Refinish if necessary.
After refacing, wash the cylinder head and valves.
After cutting the seats, apply lapping compound to the
valve face, and lap the valve using light pressure.
After lapping, wash any residual compound off the
cylinder head and valve.
Install the valve springs with the tightly wound coils
facing the combustion chamber.
Install the spring retainers.
45º
2
3
1
4
5
6
7
7