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.

This Part Fits:

Year	Make	Model	Submodel
1999-2007	Harley Davidson	FLHR Road King	Base
2007	Harley Davidson	FLHRC Road King Classic	Base
2002-2006	Harley Davidson	FLHRCI Road King Classic	Base
2003-2006	Harley Davidson	FLHRI Road King	Base
2004-2007	Harley Davidson	FLHRS Road King Custom	Base
2004-2006	Harley Davidson	FLHRSI Road King Custom	Base
1999-2007	Harley Davidson	FLHT Electra Glide Standard	Base
1999-2005,2007	Harley Davidson	FLHTC Electra Glide Classic	Base
2002-2006	Harley Davidson	FLHTCI Electra Glide Classic	Base
2007	Harley Davidson	FLHTCU Electra Glide Ultra Classic	Base
2002-2006	Harley Davidson	FLHTCUI Electra Glide Ultra Classic	Base
2003-2006	Harley Davidson	FLHTI Electra Glide Standard	Base
2006-2007	Harley Davidson	FLHX Street Glide	Base
2006	Harley Davidson	FLHXI Street Glide	Base
2006	Harley Davidson	FLST Heritage Softail	Base
2000-2012	Harley Davidson	FLSTC Heritage Softail Classic	Base
2002-2006	Harley Davidson	FLSTCI Heritage Softail Classic	Base
2000-2012	Harley Davidson	FLSTF Fat Boy	Base
2010-2012	Harley Davidson	FLSTFB Fat Boy Lo	Base
2001-2006	Harley Davidson	FLSTFI Fat Boy	Base
2006	Harley Davidson	FLSTI Heritage Softail	Base
2005-2012	Harley Davidson	FLSTN Softail Deluxe	Base
2005-2006	Harley Davidson	FLSTNI Softail Deluxe	Base
2000-2003	Harley Davidson	FLSTS Heritage Springer	Base
2005-2007	Harley Davidson	FLSTSC Softail Springer Classic	Base
2005-2006	Harley Davidson	FLSTSCI Softail Springer Classic	Base
2001-2003	Harley Davidson	FLSTSI Heritage Springer	Base
1999-2002,2007	Harley Davidson	FLTR Road Glide	Base
2002-2006	Harley Davidson	FLTRI Road Glide	Base
2010-2011	Harley Davidson	FLTRX Road Glide Custom	Base
2008-2009	Harley Davidson	FXCW Rocker	Base
2008-2011	Harley Davidson	FXCWC Rocker C	Base
1999-2007	Harley Davidson	FXD Dyna Super Glide	Base
2007	Harley Davidson	FXDB Street Bob	Base
2006	Harley Davidson	FXDBI Street Bob	Base
2005,2007	Harley Davidson	FXDC Super Glide Custom	Base
2005-2006	Harley Davidson	FXDCI Super Glide Custom	Base
2004-2006	Harley Davidson	FXDI Dyna Super Glide	Base
2006	Harley Davidson	FXDI35 Dyna 35th Anniversary Super Glide	Base
1999-2005,2007	Harley Davidson	FXDL Dyna Low Rider	Base
2004-2006	Harley Davidson	FXDLI Dyna Low Rider	Base
1999-2000	Harley Davidson	FXDS-Conv Dyna Convertible	Base
1999-2007	Harley Davidson	FXDWG Dyna Wide Glide	Base
2004-2006	Harley Davidson	FXDWGI Dyna Wide Glide	Base
1999-2004	Harley Davidson	FXDX Dyna Super Glide Sport	Base
2004-2005	Harley Davidson	FXDXI Dyna Super Glide Sport	Base
2001-2003	Harley Davidson	FXDXT Dyna Super Glide T-Sport	Base
2000-2009	Harley Davidson	FXST Softail Standard	Base
2000-2009	Harley Davidson	FXSTB Night Train	Base
2001-2006	Harley Davidson	FXSTBI Night Train	Base
2007-2010	Harley Davidson	FXSTC Softail Custom	Base
2000-2007	Harley Davidson	FXSTD Softail Deuce	Base
2001-2006	Harley Davidson	FXSTDI Softail Deuce	Base
2001-2006	Harley Davidson	FXSTI Softail Standard	Base
2000-2006	Harley Davidson	FXSTS Springer Softail	Base
2001-2006	Harley Davidson	FXSTSI Springer Softail	Base