K&N High-Flow Air Intake System Adds Horsepower to 2008 - 2015 Harley Twin Cams

K&N RK-3947B intake for Harley-Davidson motorcycles

K&N RK-3947B intake for Harley-Davidson motorcycles

Most Harley riders would love a bolt-on solution that adds a little extra acceleration when passing slower traffic up a hill or going around a truck. K&N has the answer for many 2008 – 2015 Harley-Davidson FLT and FLH riders with its RK3947B high-flow air intake system, which adds over seven horsepower with a simple installation.

The Twin Cam motorcycle engines have been manufactured by Harley-Davidson since 1998. Although these engines differ from the Evolution engine, which has been evolved from the series of single camshaft, overhead valve motors that were first released in 1936, they share a number of characteristics. Both engines feature two cylinders in a traditional Harley-Davidson 45° V-twin configuration, both are air-cooled (although some touring models use liquid cooling for the cylinder heads) and activate valves via push-rods.

When Electronic Fuel Injection (EFI) first became available in 2001, it opened up a world of opportunities for upgrading and customizing the performance of the Twin Cam engine.

In order to get the most out of your EFI system, you need an air filter system that flows better than stock. The K&N RK3947B high-flow air intake system has been developed to add horsepower and acceleration to your Harley through an increase of up to 50% more air flow, which the EFI system can turn into more power.>

K&N RK-3947B intake installed on Harley-Davidson motorcycles

K&N RK-3947B intake installed on Harley-Davidson motorcycles

The K&N high-flow air intake system eliminates the stock OE air cleaner assembly and replaces it with a complete intake assembly. The sturdy, custom aluminum backing plate mounts directly to the throttle body via an aluminum integrated, internal-run breather system. Inside the intake system is an oversized K&N air filter feeding a dyno tuned velocity stack specific to the Twin Cam which directs airflow to the engine. A black powder coated aluminum cover with a subtle K&N logo finishes off the package.

And the performance benefits of the K&N RK3947B intake system isn’t just advertising copy. In fact, K&N dyno tests show an estimated 7.03 horsepower increase on an otherwise stock 2015 Harley Street Glide.

The key to improved airflow through K&N air filters is that they’re manufactured from several layers of pre-oiled cotton filter media, rather than restrictive paper often found in many replacement filters. K&N filters also provides outstanding microfiltration, removing the most damaging particles to your engine, to ensure a long engine life for your Harley. K&N conducts its own in-house ISO 5011 air filter efficiency testing, which follows International Standard Organization procedures to verify that each K&N air filter meets these standards.

The only maintenance required for a K&N Harley intake kit is a service you can do yourself in no time at all. Once a year, depending on riding conditions, with just the K&N air filter cleaning kit you can easily renew your air filter, and prepare it for another year of riding. Your one K&N air filter is designed to last for the lifetime of your bike, which K&N guarantees will perform for up to 1,000,000 miles or 10 years without requiring replacement. For full details visit the K&N Million Mile Limited Warranty.

To find additional K&N upgrades for cars, trucks, scooters, motorcycles, motorhomes, or just about anything powered by an engine, use the K&N search by vehicle tool. Find an authorized K&N dealer nearby using the K&N dealer search.

The Harley RK3947B fits the following bikes:

K&N RK-3947B intake parts included

K&N RK-3947B intake parts included

2015 HARLEY DAVIDSON FLTRXS ROAD GLIDE SPECIAL 103 CI
2015 HARLEY DAVIDSON FLTRX ROAD GLIDE 103 CI
2015 HARLEY DAVIDSON FLRT FREEWHEELER 103 CI
2015 HARLEY DAVIDSON FLHXS STREET GLIDE SPECIAL 103 CI
2015 HARLEY DAVIDSON FLHX STREET GLIDE 103 CI
2015 HARLEY DAVIDSON FLHTKL ULTRA LIMITED LOW 103 CI
2015 HARLEY DAVIDSON FLHTK ULTRA LIMITED 103 CI
2015 HARLEY DAVIDSON FLHTCUTG TRI GLIDE ULTRA 103 CI
2015 HARLEY DAVIDSON FLHTCUL ELECTRA GLIDE ULTRA CLASSIC LOW 103 CI
2015 HARLEY DAVIDSON FLHTCU ELECTRA GLIDE ULTRA CLASSIC 103 CI
2015 HARLEY DAVIDSON FLHR ROAD KING 103 CI
2014 HARLEY DAVIDSON FLHX STREET GLIDE 103 CI
2014 HARLEY DAVIDSON FLHTK ELECTRA GLIDE ULTRA LIMITED 103 CI
2014 HARLEY DAVIDSON FLHTCUTG TRI GLIDE ULTRA 103 CI
2014 HARLEY DAVIDSON FLHTCU ELECTRA GLIDE ULTRA CLASSIC 103 CI
2014 HARLEY DAVIDSON FLHR ROAD KING 103 CI
2013 HARLEY DAVIDSON FLTRX ROAD GLIDE CUSTOM 103 CI
2013 HARLEY DAVIDSON FLTRU ROAD GLIDE ULTRA 103 CI
2013 HARLEY DAVIDSON FLHX STREET GLIDE 103 CI
2013 HARLEY DAVIDSON FLHTK ELECTRA GLIDE ULTRA LIMITED 103 CI
2013 HARLEY DAVIDSON FLHTCUTG TRI GLIDE ULTRA CLASSIC 103 CI
2013 HARLEY DAVIDSON FLHTCU ULTRA CLASSIC ELECTRA GLIDE 103 CI
2013 HARLEY DAVIDSON FLHTC ELECTRA GLIDE CLASSIC 103 CI
2013 HARLEY DAVIDSON FLHRC ROAD KING CLASSIC 103 CI
2013 HARLEY DAVIDSON FLHR ROAD KING 103 CI
2012 HARLEY DAVIDSON FLTRX ROAD GLIDE CUSTOM 103 CI
2012 HARLEY DAVIDSON FLTRU ROAD GLIDE ULTRA 103 CI
2012 HARLEY DAVIDSON FLHX STREET GLIDE 103 CI
2012 HARLEY DAVIDSON FLHTK ELECTRA GLIDE ULTRA LIMITED 103 CI
2012 HARLEY DAVIDSON FLHTCUTG TRI GLIDE ULTRA CLASSIC 103 CI
2012 HARLEY DAVIDSON FLHTCU ELECTRA GLIDE ULTRA CLASSIC 103 CI
2012 HARLEY DAVIDSON FLHTC ELECTRA GLIDE CLASSIC 103 CI
2012 HARLEY DAVIDSON FLHRC ROAD KING CLASSIC 103 CI
2012 HARLEY DAVIDSON FLHR ROAD KING 103 CI
2011 HARLEY DAVIDSON FLTRX ROAD GLIDE CUSTOM 96 CI
2011 HARLEY DAVIDSON FLTRU ROAD GLIDE ULTRA 103 CI
2011 HARLEY DAVIDSON FLHXXX STREET GLIDE TRIKE 103 CI
2011 HARLEY DAVIDSON FLHX STREET GLIDE 96 CI
2011 HARLEY DAVIDSON FLHTP ELECTRA GLIDE POLICE 103 CI
2011 HARLEY DAVIDSON FLHTK ELECTRA GLIDE ULTRA LIMITED 103 CI
2011 HARLEY DAVIDSON FLHTCUTG TRI GLIDE ULTRA CLASSIC 103 CI
2011 HARLEY DAVIDSON FLHTCU ULTRA CLASSIC ELECTRA GLIDE 96 CI
2011 HARLEY DAVIDSON FLHTC ELECTRA GLIDE CLASSIC 96 CI
2011 HARLEY DAVIDSON FLHRC ROAD KING CLASSIC 103 CI
2011 HARLEY DAVIDSON FLHR ROAD KING 96 CI
2011 HARLEY DAVIDSON FLHP ROAD KING POLICE 103 CI
2010 HARLEY DAVIDSON FLTRX ROAD GLIDE CUSTOM 96 CI
2010 HARLEY DAVIDSON FLHXXX STREET GLIDE TRIKE 103 CI
2010 HARLEY DAVIDSON FLHX STREET GLIDE 96 CI
2010 HARLEY DAVIDSON FLHTP ELECTRA GLIDE POLICE 103 CI
2010 HARLEY DAVIDSON FLHTK ELECTRA GLIDE ULTRA LIMITED 103 CI
2010 HARLEY DAVIDSON FLHTCUTG TRI GLIDE ULTRA CLASSIC 103 CI
2010 HARLEY DAVIDSON FLHTCU ULTRA CLASSIC ELECTRA GLIDE 96 CI
2010 HARLEY DAVIDSON FLHTC ELECTRA GLIDE CLASSIC 96 CI
2010 HARLEY DAVIDSON FLHRC ROAD KING CLASSIC 96 CI
2010 HARLEY DAVIDSON FLHR ROAD KING 96 CI
2010 HARLEY DAVIDSON FLHP ROAD KING POLICE 103 CI
2009 HARLEY DAVIDSON FLTR ROAD GLIDE 96 CI
2009 HARLEY DAVIDSON FLHX STREET GLIDE 96 CI
2009 HARLEY DAVIDSON FLHTP ELECTRA GLIDE POLICE 103 CI
2009 HARLEY DAVIDSON FLHTCUTG TRI GLIDE ULTRA CLASSIC 103 CI
2009 HARLEY DAVIDSON FLHTCU ULTRA CLASSIC ELECTRA GLIDE 96 CI
2009 HARLEY DAVIDSON FLHTC ELECTRA GLIDE CLASSIC 96 CI
2009 HARLEY DAVIDSON FLHT ELECTRA GLIDE STANDARD 96 CI
2009 HARLEY DAVIDSON FLHRC ROAD KING CLASSIC 96 CI
2009 HARLEY DAVIDSON FLHR ROAD KING 96 CI
2009 HARLEY DAVIDSON FLHP ROAD KING POLICE 103 CI
2008 HARLEY DAVIDSON FLTR ROAD GLIDE 96 CI
2008 HARLEY DAVIDSON FLHX STREET GLIDE 96 CI
2008 HARLEY DAVIDSON FLHTCU ULTRA CLASSIC ELECTRA GLIDE 96 CI
2008 HARLEY DAVIDSON FLHTC ELECTRA GLIDE CLASSIC 96 CI
2008 HARLEY DAVIDSON FLHT ELECTRA GLIDE STANDARD 96 CI
2008 HARLEY DAVIDSON FLHRC ROAD KING CLASSIC 96 CI
2008 HARLEY DAVIDSON FLHR ROAD KING 96 CI

Not legal for sale or use on any pollution controlled motor vehicle in California or states adopting California emission procedures. See knfilters.com for CARB status on each part for a specific vehicle.

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