Bel-Ray® Thumper Racing Synthetic Ester Blend 4T Engine Oil is a 4-stroke motorcycle racing oil that combines the finest quality synthetic esters and highly-refined mineral base oils specifically engineered for today's 4-stroke single cylinder, multi-valve racing engines. Provides maximum anti-wear protection for valve-trains, rings, cylinders and pistons. Delivers maximum horsepower while providing consistent clutch performance. Meets API SM and JASO MA2 requirements. Suitable for air-cooled/liquid-cooled 4-stroke engines and wet clutches. For use in all 4-stroke engines requiring an oil meeting the API SG / SH / SJ / SL / SM standards. For use in all 4-stroke motorcycles with or without wet clutches including those specifying the use of a JASO MA / MA1 / MA2 qualified oil. Superior anti-wear - Reduced cylinder and ring wear. Longer bearing life.