Yamaha RAPTOR YFM660R Manual Del Propietário página 280

10. Add sufficient oil of the recommended
type to raise it to the correct level, and
then install and tighten the oil tank filler
cap.
Recommended engine oil:
See page 10-2.
CAUTION:
G
In order to prevent clutch slippage (since
the engine oil also lubricates the clutch),
do not mix any chemical additives with
the oil or use oils of a higher grade than
"CD". In addition, do not use oils labeled
"ENERGY CONSERVING II" or higher.
G Make sure that no foreign material enters
the crankcase.
8-27