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K&N RK-3948B Air Intake Adds Style and Higher Performance to Harley-Davidson FL Models

K&N RK-3948B intake installed on a Harley-Davidson FL model

The design of the RK-3948B intake matches the lines of the Harley engine perfectly

The venerable Harley-Davidson FL line of motorcycles can be defined, in part, by classic styling. That being said, there is always room for some welcome creativity in the styling of performance upgrades. K&N’s new RK-3948B Big 8 intake system combines a classic black intake look, with just a touch of chrome bling. The result is a styling aesthetic that enhances any Harley.

Before we get to the impressive performance and protection aspects of the RK-3948B, let’s look closer at the visual design elements. The unique shape of the intake's frame and filter compliments the lines of the V-twin engine configuration. The intake cap is finished in a subtle matte black that sits as the perfect backdrop for the three chrome accents. Simply put, the look works.

Resting behind that fine looking exterior is an engineered custom aluminum mounting system that allows an increased airflow to the throttle body. The intake has an integrated, internal-run breather system. Sandwiched between the intake mount and the cover is a K&N high-flow air filter element.

K&N RK-3948B intake for Harley-Davidson FL models back view

K&N's engineers have developed a mounting system that is clean and efficient

That filter element is composed of multiple layers of cotton gauze filter media formed into numerous pleats that flow loads of clean air to the V-twin engine. It is no secret that more airflow increases the potential for significant power gains.

So what kind of horsepower boost can you expect from the RK-3948B? K&N’s rigorous in-house testing resulted in an estimated gain of almost 7 horsepower when the intake was installed on an otherwise stock 2017 107ci Harley-Davidson Road Glide. You can see the test protocols and the performance charts on the dyno chart link on the product details page.

That impressive power increase does not come at the expense of engine protection. The K&N filter incorporates the oil-impregnated media that has over four decades of real-world testing and proven protection. When it is time to clean that element, K&N makes a number of kits and cleaning products that make the job simple and convenient.

K&N RK-3948B intake for Harley-Davidson FL models parts view

Everything that is needed for easy installation is included in the RK-3948B kit

Enough talking already. Isn’t it time that you bolt on some style and performance? The installation of the RK-3948B is straightforward and K&N’s instruction sheet provides clear photos of each step of the process. The filter element comes pre-oiled and ready to install.

The RK-3948B intake fits the models listed below. Check K&N's online application search tool for all of your filtration needs.

2017 HARLEY DAVIDSON FLTRXS ROAD GLIDE SPECIAL 107 CI - All Models
2017 HARLEY DAVIDSON FLTRX ROAD GLIDE 107 CI - All Models
2017 HARLEY DAVIDSON FLTRU ROAD GLIDE ULTRA 107 CI - All Models
2017 HARLEY DAVIDSON FLRT FREEWHEELER 107 CI - All Models
2017 HARLEY DAVIDSON FLHXS STREET GLIDE SPECIAL 107 CI - All Models
2017 HARLEY DAVIDSON FLHX STREET GLIDE 107 CI - All Models
2017 HARLEY DAVIDSON FLHTKL ULTRA LIMITED LOW 107 CI - All Models
2017 HARLEY DAVIDSON FLHTK ULTRA LIMITED 107 CI - All Models
2017 HARLEY DAVIDSON FLHTCUTG TRI GLIDE ULTRA 107 CI - All Models
2017 HARLEY DAVIDSON FLHTCU ELECTRA GLIDE ULTRA CLASSIC 107 CI - All Models
2017 HARLEY DAVIDSON FLHR ROAD KING 107 CI - All Models


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