Moroso 85710 Air-Oil Separator Catch Can Kit for Harley-Davidson V-Twin Polished

The Moroso 85710 is a universal air-oil separator and catch can system engineered specifically for Harley-Davidson EVO, Twin Cam, and Sportster engines. Designed to keep the cylinder head breather system fully functional, this polished kit eliminates the harmful effects of crankcase oil mist and blow-by that recirculate back into the intake.

From the factory, a motorcycle's breather system routes excess crankcase vapors, unburned fuel, residual oil, and moisture directly back into the intake tract. The Moroso air-oil separator plumbs inline with the breather system, capturing those contaminants before they can re-enter the engine — reducing detonation, knock, and harmful deposits on valves, pistons, and intake surfaces.

Key Features:

• Keeps the H-D cylinder head breather system fully functional while filtering crankcase vapors, oil mist, and condensation
• Protects the air filter, throttle body, intake, pistons, and valves from excessive oil and carbon buildup
• Separates vapors from engine breathing — clean, filtered air recirculates back into the intake while contaminants are collected in the canister
• Does not vent to atmosphere, keeping collected oil contained in the canister and off the motorcycle
• Two-piece body unscrews for easy cleaning and servicing
• Can be drained at regular oil change intervals as a routine service item
• Available in a polished finish to complement custom and stock builds
• Proudly Made in the U.S.A.

The Moroso 85710 is a universal kit sold as a complete system. Periodic draining of the canister is required as part of normal maintenance.