Moroso Air/Oil Separator - V-Twin Univ. Breather — Harley-Davidson Electra Glide Ultra Classic, Softail Heritage Classic, Softail Fat Boy (1991-2017)

Moroso air-oil separator catches crankcase vapors, oil mist, and condensation before they reach your intake system, keeping your air filter, throttle body, intake valves, and pistons cleaner. The canister design traps oil inside rather than venting to atmosphere, protecting your bike and the ground.

Features

• Filters crankcase vapors, unburnt fuel, residual oil, and moisture
• Reduces detonation and knock by cleaning intake tract
• Two-piece body unscrews for easy cleaning and maintenance
• Closed-loop design — does not vent to atmosphere
• Made in the U.S.A.

Specifications

• Brand: Moroso
• Manufacturer Part #: 85710
• UPC: 84663857102
• Length: 9 in
• Width: 6 in
• Height: 5 in
• Weight: 2 lbs

Frequently Asked Questions

What does this separator do that a standard breather doesn't?

Standard breather vents oil mist and vapors back into the intake. This separator catches and filters them, keeping your intake and valves cleaner while preventing oil from hitting the ground.

How often do I need to clean the canister?

Check at regular service intervals. The two-piece design unscrews for easy emptying and cleaning when oil accumulation is visible.

Does this affect my stock breather function?

No — the system plumbs inline with your factory breather, keeping it fully functional while filtering what goes back into the engine.

Will this help with performance and reliability?

Yes. By removing oil mist and vapors from the intake, you reduce carbon buildup on valves and pistons, which can improve combustion efficiency and reduce knock.