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K&N RK-3951 Intake System-Harley Davidson

Custom Assemblies > Intake System-Harley Davidson
Rating Star 1 Rating Star 2 Rating Star 3 Rating Star 4 Rating Star 5   4.0 out of 5 stars   1 Customer Review
  • Guaranteed to increase horsepower
  • Designed to improve throttle response and engine sound
  • Cast aluminum high-volume, performance air intake housing in black
  • Washable and reusable K&N High-Flow cotton air filter that provides outstanding performance and protection
  • Integrated internal velocity stack
  • Built-in breathers replace external OE breathers
  • Easy to install, usually in 90 minutes or less
The K&N RK-3951 Intake System-Harley Davidson fits some Harley Davidson FLHP Road King Police, Harley Davidson FLHR Road King, Harley Davidson FLHRC Road King Classic, Harley Davidson FLHRSE4 Screamin Eagle Road King, Harley Davidson FLHT Electra Glide Standard, Harley Davidson FLHTC Electra Glide Classic, Harley Davidson FLHTP Electra Glide Police, Harley Davidson FLHX Street Glide, Harley Davidson FLHXS Street Glide Special, Harley Davidson FLRT Freewheeler, Harley Davidson FLS Softail Slim, Harley Davidson FLSS Softail Slim S, Harley Davidson FLSTC Heritage Softail Classic, Harley Davidson FLSTF Fat Boy, Harley Davidson FLSTFB Softail Fat Boy Lo, Harley Davidson FLSTFBS Fat Boy S, Harley Davidson FLSTN Softail Deluxe, Harley Davidson FLTR Road Glide, Harley Davidson FLTRX Road Glide, Harley Davidson FLTRX Road Glide Custom, Harley Davidson FLTRXS Road Glide Special, and Harley Davidson FXSB Breakout models. See vehicle applications link for details.
K&N Street Metal Air Intake Systems for Harley Davidson® motorcycles replace the restrictive stock OE air cleaner with an oversized K&N High-Flow Air Filter and a high-volume cast aluminum housing. If you’re looking for an aggressive appearance but want a significant increase in airflow, resulting in more power, this high-flow air intake system is exactly what your Harley needs. Installation is so simple, it can usually be done in 90 minutes or less. The K&N air filter is washable, reusable, pre-oiled and ready for installation. This intake system features a matte black housing with silver details and sanded fins. Internal breathers provide a sleek, clean appearance. This air intake has a classic styling with a savage appeal.

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

Product Specifications

Estimated Horsepower Gain6.04 HP @ 4907 RPM
Replacement FilterE-3987
Air Filter ColorRed
Air Filter MaterialCotton Gauze
Product StyleMotorcycle Intake System
Air Filter Height2.469 in (63 mm)
Street Legal In All US States No
TUV Approved (Europe)No
Overall Height3.25 in (83 mm)
Top MaterialBlack Powder Coated
Package Contents1 Air Filter
Package Quantity1
Weight5 lb (2.3 kg)
Product Box Height4.8 in (122 mm)
Product Box Length12 in (305 mm)
Product Box Width9.5 in (241 mm)
California RestrictedNot legal for sale or use in California
Housing MaterialAluminum
Mounting Hardware IncludedYes
Horsepower gains based on similar vehicle dynamometer test. Results will vary.

K&N RK-3951 Intake System-Harley Davidson Product Reviews

Saturday, June 3, 2017 - Part RK-3951
Didn't add as much perfomance as expected on my 15 HD FLSTC 103CI with Vance and Hines slip-ons and Vance and Hines Fuelpak. Overall, great quality, arrived on time and very easy to install. Took less than half hour.

Charles Sowa
Nokomis, Florida