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K&N RK-3910-1

Custom Assemblies > Intake System-Harley Davidson
Rating Star 1 Rating Star 2 Rating Star 3 Rating Star 4 Rating Star 5   5.0 out of 5 stars   12 Customer Reviews
  • Designed to increase horsepower & torque
  • Dyno-tuned velocity stack
  • Washable and reusable
  • Excellent air filtration
K&N's RK Series was developed to get more horsepower from your Twin Cam Harley-Davidson engine. Built around the legendary K&N High-Flow Air Filter, the this RK Series assembly includes an innovative powder coated billet aluminum back plate that eliminates external breathers and features a built-in, dyno-tuned velocity stack. The result is a significant airflow increase to the engine without sacrificing filtration. This RK Series assembly retains a factory appearance by utilizing the stock air cleaner cover. The RK-3910-1 comes with a larger air filter and longer spacers than the RK-3909-1.

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

Product Specifications

Estimated Horsepower Gain10.76 HP @ 5206 RPM
Air Filter ColorRed
Air Filter Height2.188 in (56 mm)
Air Filter MaterialCotton Gauze
Air Filter Outlet ShapeRound
Air Filter ShapeOval
CARB EO NumberD-269-35/55
Clamp MaterialNo Clamps Required
Clamp StyleNo Clamps Required
Clamps IncludedNo Clamps Included
Inlet Diameter2.25 in (57 mm)
Mounting Hardware IncludedYes
Neck Flange2.25 in (57 mm)
Overall Height2.188 in (56 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-3980
Size9 Inch
Street Legal In All US StatesSee Application Link Above
Top Material/FinishBlack Powder Coated
Top StyleMetal
TUV Approved (Europe)No
Weight3.3 lb (1.5 kg)
Horsepower gains based on similar vehicle dynamometer test. Results will vary.

K&N RK-3910-1 Product Reviews

Thursday, May 26, 2016 - Part RK-3910-1
Easy to install. Cover/cleaner sticks out a little farther than stock, but not an issue. She's defiantly breathing better, seems to be pulling harder.

Kevin Wood
Thursday, April 28, 2016 - Part RK-3910-1
Part No.RK-3910-1 does not fit my application as mentioned on their site. I called customer service and had the privilege of working with James M. I couldn't be happier with how he handled the situation. I received the correct part last night and I am looking forward to installing it. K&N makes great products and I will continue to use them in all of my vehicles.

Brian D
Wednesday, March 2, 2016 - Part RK-3910-1
On time. Fits perfect and bike runs better than ever.

Thursday, June 4, 2015 - Part RK-3910-1
It really made my bike breathe and it runs much better now

Houston, Texas
Thursday, May 14, 2015 - Part RK-3910-1
Received on time, quality product and exactly what I was looking for.

Robert Pate
Fayetteville, North Carolina
Monday, February 23, 2015 - Part RK-3910-1
Due to adverse weather conditions here in the NE I haven't had a chance to install or test the setup yet but I am looking forward to getting it installed on my bike. What I like most is the ability to use my stock air cleaner cover with this unit. I had a slight mishap while trying to install in sub freezing temps and broke a component and the staff at K&N did the right thing and had a replacement at my door in 3 days at no charge. I will wait until it warms up some here so I can get it installed and out for a test ride. This is the last step in a 103 inch build and hope to have her on the road soon.

Mr Peter Petrauskas
New York
Wednesday, April 23, 2014 - Part RK-3910-1
Excellent fit and finish. I can definitely feel the difference in torque over the stock element!

Mike Roberts
Battle Creek, Michigan