Castrol Power RS V-Twin 20W-50 Full Synthetic 4-Stroke Motorcycle Oil (06116) Provides excellent protection against thermal and viscosity breakdown under high temperatures generated by air-cooled V-Twin engines. Delivers proven wet clutch performance allowing for smooth operation and protection. Suitable for all Japanese and North American 4-stroke motorcycles where SAE 20W-50 is recommended. API SERVICE: Exceeds API SL JASO (T903): JASO MA-2