Arlen Ness 18-821

Big Sucker™ Stage 2 air cleaners retain all the performance gaining features of the Stage 1 plus a 20% larger filter fore even more airflow. Each Stage 2 features our patented hidden breather backing plate that is o-ringed at the heads and exits inside the mouth of the throttle body, eliminating the need for any external hoses or hardware

• Smooth Stage 2 Cover 
• Increases Horsepower & Torque 
• 20% Larger Filter Than Stage 1 
• Patented Hidden Breather Technology 
• Pre-Oiled High Performance Filters
• One-Piece Aluminum Backing Plate 
• Radius Air Inlet for Unobstructed Airflow  

Air Cleaner Backing Plate:

• Made from aluminum and finished to spec by CNC machine 
• The backing plate's one-piece design features our patented hidden breather technology, each breather is o-ringed at the heads and exits at the mouth of the throttle body. This creates a virtually closed look system which eliminates the need for any external hoses or hardware
• Smooth radius air inlet engineered to provide maximum airflow directly into the engine 
• Available finishes: Standard Raw / Chrome / Black Powdercoat 

Performance Air Filter:

• Each Big Sucker performance filter is handmade in the USA 
• 20% larger filter then Stage 1 
• Performance filters are available in red pre-oiled cotton or Black cotton /Stainless steel jacket
• Red pre-oiled cotton performance filters are made from 4 layers of surgical grade cotton.  Filters are washable/re-useable, filter service kits are available separately
• Black cotton /Stainless steel jacket performance filters are made from a black oiled cotton filter element that is wrapped in a stainless steel jacket. Black cotton /Stainless steel jacket require oil, they are also washable/re-useable 

Air Cleaner Covers and Components:

• Smooth Stage 2 custom cover

Backing Plate (Fitment Specific)

08-16 FLT/16-17 FBW Softail & Dyna: Black 18-590

99-17 Twin Cam (Exc. FBW & 01 FI): Black 18-591 

99-01 Fuel Injected (FI) FLT: Black 18-593 

93-99 Evolution: Black 18-592 

 88-up XL Sportster: Black 18-594 

 Hardware Kit (Fitment Specific)

 08-16 FLT/16-17 FBW Softail & Dyna: 18-539

99-17 Twin Cam (Exc. FBW & 01 FI): 18-539

99-01 Fuel Injected (FI) FLT: 18-542

93-99 Evolution: 18-541

88-up XL Sportster: 18-543

Stage 2 Air Filter, Red Pre-Oiled

08-16 FLT/16-17 FBW Softail & Dyna: 18-081

99-17 Twin Cam/88-up XL/93-99 Evo/99-01 FI FLT: 18-099

Stage 2 Air Filter, Synthetic

08-16 FLT/16-17 FBW Softail & Dyna: 50-085

99-17 Twin Cam/88-up XL/93-99 Evo/99-01 FI FLT: 50-086

 Smooth Stage 2 Air Cleaner Cover, Black: 18-771 

• 99-17 Twin Cam (Exc. FBW & 99-01 FI FLT)
• 08-16 FLT / 16-17 FLST & FXDLS (FBW)
• 91-up XL Sportster
• 93-99 Evo (Evolution) 
• 99-01 FI (Fuel Injected) FLT 

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