Arlen Ness 18-393

The new Big Sucker™ Stage 1 performance intake for Milwaukee-Eight® (M8) engines adds new features to the original industry leading air cleaner. The new patent-pending hidden breather system is o-ringed at the heads, passes through the backing plate and exits inside the mouth of the throttle body through proprietary shooter tubes

• Knuckle Stage 1 Cover 
• Increases Horsepower & Torque 
• Eliminates Oil Blow-bye Issues Associated with M8 Engines
• Black Pre-Oiled High Performance Filter 
• Patent-Pending Hidden Breather Technology 
• Patent-Pending Oil Catch / Reservoir 
• One-Piece Aluminum Backing Plate 
• Aluminum Filter Top Plate  

Aluminum Backing Plate For Milwaukee-Eight™ Engines 

• New patent-pending hidden breather backing plate technology. Each breather is o-ringed at the heads, passes through the backing plate and exits inside the mouth of the throttle body through specially formed shooter tubes
• Shooter tubes are specially formed to flow with the radius air inlet to provide efficient engine breathing without adversely effecting airflow 
• Helps to eliminate oil blow-bye  issues associated with performance intakes on M8 engines 
• Integrated patent-pending oil catch stops any excess breather oil from reaching the air filter. Oil catch is serviceable, simply bolt-on and off when your ready to wash/service the air filter 
• Formed aluminum filter plate design with integrated mounting studs eliminates any internal mounting hardware  
• Outer filter lip covers the urethane on the base of the air filter for a clean look that leaves only filter media exposed 
• Chrome finish 

Performance Air Filters: Milwaukee-Eight Engines 

• Black pre-oiled cotton performance air filter 
• Engineered for optimum air flow and filtration
• Perimeter flow design brings in air from all sides of the filter while filtering out all harmful debris/dust
• Each filter is washable and re-useable, filter service kits are available 

Knuckle Stage 1 Outer Cover

• The Knuckle Stage 1 cover features 3D sculpted styling that extends from the face of the air cleaner to the sides of the air filter 
• CNC machined from billet aluminum 
• Chrome finish 

M8

Backing Plate Assembly: 18-394C

Backing Plate, Filter Top Plate, Stainless Hardware ¼-20 x 1-½ (2)

Breather & Oil Catch

Oil Catch: 18-392-3

Oil Catch Gasket: 18-392-3

Oil Catch Hardware, 8-32 x ¾: H-619S (2)

Shooter Tubes: BT-001

Hardware Kit: HK-18458

Breather Bolts: 18-457-4C (2)

Throttle Body Gasket: 18-457-3

Breather Bolt O-Rings: H-024-4 (4)

Throttle Body Logo Plate: 18-203-8

Logo Plate Hardware, M6 x 1.0: HM-122B (2)

Knuckle Air Cleaner Cover, Chrome: 18-768

Cover Hardware, 5/16-18 x 5/8: H-525C

Pre-Oiled Air Filter, Black: 18-090

17-2023 M8 MODELS (EXCEPT: 2023 FLHXSE & FLTRXSE)

•  2017-up FLT Touring / Bagger Models: FLHT / FLHR / FLHX / FLTRX / FLTRU / H-D FL Trike 
• 2018-up Softail™ Models 

FITMENT DISCLAIMER

Fitment information is provided as a general reference only and is not guaranteed for any motorcycle, whether stock or modified. Compatibility may vary by year, model, and individual configuration.

Customers are responsible for verifying fitment prior to purchase. House of Harley-Davidson assumes no liability for purchases made based on incorrect or unverified fitment information.

Please contact our Parts Department with any questions before ordering at 414-282-2211