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MSRP $340.00 42.9% Off
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K&N RK-3947B Intake System-Harley Davidson

Custom Assemblies > Intake System-Harley Davidson
  • Guaranteed increase in horsepower
  • Replaces the stock air filter and cleaner backing plate assembly
  • Washable, oversized K&N high-flow air filter equals longer life
  • Oversized black, powder coated aluminum backing plate provides solid mounting
  • Dyno tuned velocity stack directs airflow to engine
  • Built in breathers replace external OE breathers
  • Includes K&N Million Mile Limited Warranty
The K&N RK-3947B High-Flow Air Intake System increases engine intake airflow and delivers more horsepower & torque to many Harley-Davidson FLT and FLH model motorcycles. The intake system increases power by eliminating the stock OE air cleaner and replacing it with a complete High-Flow Air Intake System. The intake system comes with a K&N air filter for high air flow and long service intervals. The K&N high-flow air filter is washable, reusable, pre-oiled and ready for installation.

[RK Series Street Metal High Flow Air Intakes for Harley-Davidson Motorcycles]

Product Specifications

Estimated Horsepower Gain7.03 HP @ 4009 RPM
Air Filter ColorRed
Air Filter Height2.125 in (54 mm)
Air Filter MaterialCotton Gauze
California RestrictedNot legal for sale or use in California
Mounting Hardware IncludedYes
Overall Height2.125 in (54 mm)
Package Quantity1
Product Box Height4.88 in (124 mm)
Product Box Length11.75 in (298 mm)
Product Box Width9.5 in (241 mm)
Product StyleMotorcycle Intake System
Replacement FilterE-3975
Street Legal In All US States No
Top Material/FinishBlack Powder Coated
TUV Approved (Europe)No
Weight4.3 lb (2 kg)
Horsepower gains based on similar vehicle dynamometer test. Results will vary.

K&N RK-3947B Intake System-Harley Davidson Product Reviews