K&N RK-3909 Custom 1-5/8in. Air Cleaner Assembly for Harley Davidson 1999-2013 Twin Cam (exc. 1999-2001 FI FLT, 2008-13 FLH, FLT)
The latest addition to 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 new 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 comes with a larger air filter and longer spacers than the RK-3909.