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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   9 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 backplate 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
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

See all reviews!
Review part RK-3910-1
Thursday, June 04, 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
Monday, March 24, 2014 - Part RK-3910-1
Order was complete and undamaged. Installed in about an hour without difficulty. That includes cleaning the throttle body. Noticable difference in throttle response as well as torque. 50mph in 6th gear roll the throttle smooth acceleration as long as you want to hold it. Works great I would recommend this Kit to everyone.

Saint Cloud, Florida
Friday, January 24, 2014 - Part RK-3910-1
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
Tuesday, November 26, 2013 - Part RK-3910-1
I buy K&N's for all of my vehicles, because I know they last longer than I have the vehicles and they can be cleaned over and over again. The fitment and quality are top notch. I have used K&N products for over forty years and haven't found anything better.

Ken Darby
Moscow, Idaho