Yamaha YZ450F(S) Owner's Service Manual page 320

VALVES AND VALVE SPRINGS
5. Install:
NOTE:
Apply the engine oil on the valve lifters.
G
Apply the molybdenum disulfide oil on the
G
valve stem end.
Valve lifter must turn smoothly when rotated
G
with a finger.
Be careful to reinstall valve lifters and pads
G
in their original place.
4 - 41
Adjusting pad 1
G
Valve lifter 2
G
ENG