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RK-3931
$149.99 USD
MSRP $262.99 43.0% Off
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K&N RK-3931

Custom Assemblies > Intake System-Harley Davidson
  • Designed to increase horsepower & torque
  • Dyno-tuned velocity stack
  • Excellent Air Filtration
  • Washable and reusable lifetime air filter
  • Not legal for highway use in states adopting California emission regulations
K&N Air Cleaner Assemblies are designed to get more horsepower from your Harley-Davidson® motorcycle. These air cleaner assemblies replace the stock air filter and backplate with an oversized K&N Air Filter and custom aluminum backing plate. These assemblies utilizes the stock cover to maintain stock appearance.

[More Information on High-Flow Air Intake Systems for Harley-Davidson Motorcycles]

Product Specifications

Estimated Horsepower Gain6.54 HP @ 5100 RPM
Air Filter ColorRed
Air Filter Height2.125 in (54 mm)
Air Filter MaterialCotton Gauze
Air Filter Outlet ShapeNot Flanged
Air Filter ShapeUnique
California RestrictedNot legal for sale or use in California
Clamp MaterialNo Clamps Required
Clamp StyleNo Clamps Required
Clamps IncludedNo Clamps Included
ColorRed
Filter MaterialCotton Gauze
Inlet Diameter2.406 in (61 mm)
Mounting Hardware IncludedYes
Neck Flange2.406 in (61 mm)
Overall Height2.5 in (64 mm)
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
Size9 Inch
Street Legal In All US States No
StyleTeardrop
Top Material/FinishAluminum
Top StyleMetal
TUV Approved (Europe)No
Weight3.1 lb (1.4 kg)
Horsepower gains based on similar vehicle dynamometer test. Results will vary.

Customer Feedback

Be the first to review part RK-3931
K&N has a great web site. I used their vehicle search to find the correct filter for my Harley Davidson 103. I really like the nut on the end of the filter as it makes installation and removal easy, no special tools required. An overall excellent experience Fast shipping as well.

Harold Brooks
San Antonio, Texas
Noticed right away that car had more power. Increased fuel mileage almost two and a half mpg. I always replace the stock filter with a K&N. I have 2 Pickups and 3 cars and a Harley Davidson Street Glide all have K&N filters.

Terry Hagg
Wheatland, Louisianna
This filter designed spared me the trouble of using the Harley Davidson stock replacement kit or the expensive naked filter assembly. I have hi-flow performance concealed in the original housing. My bike is a very new production model with limited after market products available, so Thanks K&N. Harley Davidson Street 750 owner.

Brother Andy
Maryland