Arlen Ness 18-751

Big Sucker™ Stage 1 air cleaners are engineered and proven to give your engine maximum airflow for more horsepower & torque. The patented hidden breather backing plate is o-ringed at the heads and exits inside the mouth of the throttle body for a virtually closed loop system, eliminating the need for any external hoses or hardware

• Knuckle Stage 1 Air Cleaner Cover 
• Increases Horsepower & Torque 
• Patented Hidden Breather Technology 
• Pre-Oiled High Performance Filters
• One-Piece Aluminum Backing Plate 
• Radius Air Inlet for Unobstructed Airflow  

ALUMINUM BACKING PLATE FEATURES: TWIN CAM/SPORTSTER

• One-piece aluminum backing plate  
• 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 unobstructed airflow directly into the engine 
• Matte black powdercoat finish 

Knuckle STAGE 1 AIR CLEANER COVER

• The Knuckle Stage 1 cover features 3d sculpted design that extents from the face of the air cleaner to the sides of the air filter pleats 
• CNC machined from billet aluminum 
• Black anodize finish  

PERFORMANCE AIR FILTERS: 

• Each Big Sucker performance filter is handmade in the USA
• Available in red pre-oiled cotton or synthetic filter media 
• Standard red pre-oiled cotton performance filters are made from 4 layers of surgical grade cotton for optimum flow & filtration 
• Synthetics performance filters are made from a black synthetic filter element that is wrapped in a stainless steel jacket. Synthetic filters are water resistant and do not require oil
• All Stage 1 air filters are washable/re-usable, filter tune-up kits are available separately 

TWIN CAM / SPORTSTER / EVOLUTION

BLACK BACKING PLATE (FITMENT SPECIFIC)

08-16 Touring / 16-17 Softails: 18-590

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

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

88-up XL Sportster: 18-594

HARDWARE KIT (FITMENT SPECIFIC)

 08-16 Touring /16-17 Softails: 18-530

99-17 Twin Cam (Exc. FBW & 01 FI): 18-531

99-01 Fuel Injected (FI) FLT: 18-533

88-up XL Sportster: 18-534

AIR FILTER, RED PRE-OILED

08-16 Touring / 16-17 Softails (FBW): 18-080

99-17 Twin Cam/88-up XL: 18-098

99-01 Fuel Injected (FI) FLT: 18-097

AIR FILTER, SYNTHETIC

08-16 Touring /  16-17 Softail (FBW) : 50-083

99-17 Twin Cam/88-up XL: 50-084

99-01 Fuel Injected (FI) FLT: 50-087

KNUCKLE AIR CLEANER COVER, BLACK: 18-769

COVER HARDWARE, 5/16-18 X 5/8: H-525C

99-17 TWIN CAM (EXCEPT: FBW) 

• 2001-2017 Twin Cam Delphi EFI (Fuel Injected)
• 1999-2006 Twin Cam CV Carb
• *NOTE: Will not fit Fly-By-Wire Models: 08-17 FLT Touring  / 16-17 Softail / 16-17 Dyna FXDLS & 99-01 F.I. FLT 

 08-16 TOURING / 16-17 SOFTAIL  (FBW)

• 2008-2016 FLT Touring / Bagger - FLHT / FLHR / FLHX / FLTR / H-D FL Trike 
• 2016-2017 Softails 
• 2016-2017 Dyna FXDLS 
• 2014-2015 FLSTNSE / 13-14 FXSBSE / 11-12 FLSTSE
• *NOTE: Twin Cam models equipped w/ FBW (Fly-by-Wire or Throttle-by-Wire) 

 91-UP XL SPORTSTER 

• 1991-up Sportster 883 / 1200  with CV Carb or Delphi EFI 

 99-01 FUEL INJECTED FLT 

• 1999-2001 FLT Touring Models- FLHTI / FLHRI 

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