RK-3931 Image

Custom Assemblies > Intake System-Harley Davidson

 List Price: $261.39
Your Price: $156.99

You Save 39.9%

Find a Local K&N Dealer


       

RK-3931
 
In Stock & Ready to Ship!
 Free Ground Shipping!


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]
  • 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
Available Information
Installation Instruction Sheet
RK-3931 Vehicle Applications
Air Filter Test Data
Dyno Chart - 2008 Harley Davidson Dyna Street Bob 6.54HP Increase
News Story - Add 6.5 More Horsepower to Harley Davidson Dyna Models with K&N Custom Intake Assembly


Part RK-3931 Product Specifications
Product Style: Motorcycle Intake System
Estimated Horsepower Gain: 6.54 HP @ 5100 RPM
Street Legal In All US States: No
Air Filter Color: Red
TUV Approved (Europe): No
Air Filter Height: 2.125 in (54 mm)
Air Filter Material: Cotton Gauze
Air Filter Outlet Shape: Not Flanged
Air Filter Shape: Unique
Clamp Material: No Clamps Required
Clamp Style: No Clamps Required
Color: Red
Filter Material: Cotton Gauze
Inlet Diameter: 2.4 in (61 mm)
Intake Pipe Ports: All intake tube ports needed for the specified applications are included
Mass Air Flow Sensor Adapter Included: Mass Air Flow Sensor Adapter Included When Required
Mounting Hardware Included: Yes
Neck Flange: 2.4 in (61 mm)
Overall Height: 2.5 in (64 mm)
Replacement Filter: E-3975
Size: 9 Inch
Top Material/Finish: Aluminum
Top Style: Metal
Vacuum Tubing Included: No
California Restricted: Not legal for sale or use in California
Total Height: 2.5 in (64 mm)
Weight: 3.1 lb (1.4 kg)
Product Box Length: 11.75 in (298 mm)
Product Box Width: 9.5 in (241 mm)
Product Box Height: 4.88 in (124 mm)


Horsepower gains based on similar vehicle dynamometer test. Results will vary.


Customer Feedback      Be the first to review part RK-3931

I installed the RF-1020 on my new (at the time) 2005 F-350 Harley Davidson Edition with the 6.0 diesel. The fuel mileage went up by 1.5 miles per gallon after installing the kit. Now with 352,500 miles on the truck it averages 19 MPG on the highway and still has the original RF-1020 on it. I clean and oil the filter regularly and I expect it to last forever. The chrome cover fell off the filter almost immediately but that didn't seem to make difference in performance. Thank you for a great product!
Thomas Campbell, Clearwater, Florida
Since installing the K&N intake system on my 2003 Harley Davidson Fat Boy, I have noticed considerable increase in power. My Harley is the 2003 100 Year Anniversary edition and I have several anniversary parts on it, including the breather cover. With this K&N kit, I was able to maintain the use of all specialty features. The kit was very easy to install. I had it completely installed in less than 30 minutes. Thanks again and I look forward to doing more business with you in the future.
Kevin Bearden, Ocala, Florida
The technician at K&N was very quick to respond to my query and gave me excellent detailed specifications to fit an air filter to my old Harley Davidson 3 wheel golf cart. The original was lost and this filter fit perfect and performs very well and looks much better than the original. I also run K&N on my Ford Expedition.
Robert Mongeon, Pembroke, Georgia