K&N Red Intake System for Harley DavidsonK&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