Motorcycles are prone to rust from storage, humidity and short drives. Rust can cause major damage such as roller bearing failure, wear, compression loss and blow-by. Good rust protection, however, comes by design and is not natural to motor oils. Unlike many motorcycle oils, AMSOIL Synthetic Motorcycle Oil contains special antirust agents. It passes the ASTM D1748 humidity cabinet rust test, demonstrating superior rust protection to help your engine achieve maximum performance and long life.