Yamaha WR250F(N) Owner's Service Manual page 348

VALVES AND VALVE SPRINGS
3. Install:
NOTE:
While compressing the valve spring with a
valve spring compressor 1 install the valve
cotters.
4. To secure the valve cotters onto the
CAUTION:
Hitting the valve tip with excessive force
could damage the valve.
5. Install:
NOTE:
Apply the molybdenum disulfied oil on the
valve stem end.
Apply the engine oil on the valve lifters.
Valve lifter must turn smoothly when rotated
with a finger.
Be careful to reinstall valve lifters and pads
in their original place.
4 - 41
Valve cotter
Valve spring compressor:
YM-04019/90890-04019
valve stem, lightly tap the valve tip with a
piece of wood.
Adjusting pad 1
Valve lifter 2
ENG