Yamaha YP250 Service Manual page 116

VALVES AND VALVE SPRINGS
4. Install:
S Valve cotters 1
NOTE:
Install the valve cotters while compressing the
valve spring with a valve spring compressor and
attachment 2 .
5. Secure the valve cotters onto the valve
stem by tapping lightly with a piece of wood.
CAUTION:
Do not hit so much as to damage the valve.
4-20
ENG
Valve spring compressor:
90890-04019
Attachment:
90890-04108