Spectro "Premium" primary chain & transmission lubricant is the best available fluid for lubrication of Harley-Davidson chain-cases and chain-case/transmission combinations under all conditions. The use of "Premium" primary chain-case/transmission lubricant eliminates most gear noises and clutch sticking even after prolonged periods of storage. It is formulated with special high-shear polymers to eliminate gear wear and ensure positive clutch control and smooth operation. Spectro "Premium" primary and transmission lubricant is recommended for use in all Harley-Davidson Big Twin models with closed primaries and all Sportster models with combined primary/transmission.