Moroso Air/Oil Separator For Universal V-Twin - Black 85711The Moroso air oil separator catch can system keeps the H D cylinder head breather system fully functional. It filters out crankcase vapors, oil mist & condensation that normally vent to the intake system. This will keep your air filter, throttle body, intake,pistons & valves free of excessive oil and carbon build up. Our system is different than others on the market. It separates the vapors breathing from your engine, collecting them in our air oil