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K&N RK-3910-1 5.0 out of 5 stars 7 Customer Reviews
Custom Assemblies > Intake System-Harley Davidson

List Price: $214.92
Your Price: $145.99

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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]
  • Designed to increase horsepower & torque
  • Dyno-tuned velocity stack
  • Washable and reusable
  • Excellent air filtration

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
Clamp MaterialNo Clamps Required
Clamp StyleNo Clamps Required
Filter MaterialCotton Gauze
Inlet Diameter2.25 in (57 mm)
Intake Pipe PortsAll intake tube ports needed for the specified applications are included
Mass Air Flow Sensor Adapter IncludedMass Air Flow Sensor Adapter Included When Required
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
Vacuum Tubing IncludedYes
Weight3.3 lb (1.5 kg)
Horsepower gains based on similar vehicle dynamometer test. Results will vary.

Product Reviews

  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
  Excellent fit and finish. I can definitely feel the difference in torque over the stock element!
Mike Roberts Battle Creek, Michigan
  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.
Bill Saint Cloud, 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
  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
  Good product. Performs exactly as described. Major pain, however, that the kit and installation was not available DURING the Sturgis Bike Rally (where I purchased)!
Rick Stone Knoxville, Tennessee
  Upgraded my 2008 96ci Rocker-C with a RK-3910-1 and it's like riding a new bike. I am amazed at the difference. More power throughout the band for better 2-up riding. Motor seems to run easier and a bit cooler too. Money well spent. Highly recommend this product!
Rick Texas