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K&N

K&N Cold Air Intake System: High-Flow Air Filter, Increase Performance & Acceleration: Compatible with 2017-2023 Harley Davidson: (See Product Description for Select Models), RK-3956

  • Based on 203 reviews
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Availability: In Stock.
Fulfilled by Amazon
Arrives Thursday, Jun 25
Order within 9 hours and 49 minutes
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Features

  • DYNO TESTING YOU CAN TRUST: K&N air intake horsepower/torque testing is performed on wheel-based dynamometers and the reports are included with each intake system.
  • IMPROVED ENGINE SOUND - HEAR THE GROWL: K&Ns intake systems allow your engine to breathe and sound as it should- your engine will growl on acceleration and return to quiet once at speed.
  • BETTER ACCELERATION: K&N Air intake kit improves acceleration and uphill performance by improving throttle response, overall horsepower and torque. Excellent for daily and highway driving.
  • PREMIUM ENGINE PROTECTION FROM A TRUSTED BRAND: K&N air intake will not void manufacturer vehicle warranty & No-Hassle Lifetime Limited Warranty protects for the life of your vehicle.
  • HIGH-FLOW REUSABLE AIR FILTER: 4 layers of pleated, breathable cotton with K&Ns red filter oil to absorb dirt & dust particles, allowing clean air to continue flowing into your engine, only needs cleaning every 100k miles under normal highway conditions.
  • EASY TO INSTALL: Includes detailed, step-by-step instructions & all necessary parts- the entire air intake system can typically be installed in less than 60 minutes with basic hand tools.
  • MADE IN THE USA: Proudly made in the USA for trusted quality & reliability and backed by US based customer support.

Description

K&N is the inventor of the Air Intake System and has over 50 years of experience in the performance filtration industry. Proudly designed and manufactured in the USA, this premium cold air intake system is specifically designed for your vehicle and is dyno tested to provide a guaranteed increase in horsepower. It features a high flow intake tube, custom heat shield, and oversized K&N Washable High-Flow Cotton Air Filter for ultimate airflow. This Intake system replaces the restrictive OEM air box to provide an improved driving experience for daily driving or towing. It installs easily in about 60 minutes and is backed by a No-Hassle Lifetime Limited Warranty and will not void your factory warranty.Compatible Vehicles:2018-2020 HARLEY DAVIDSON FLDE Deluxe2018-2019 HARLEY DAVIDSON FLFB Fat Boy2018-2023 HARLEY DAVIDSON FLFBS Fat Boy HARLEY DAVIDSON FLHC Heritage Classic2018-2023 HARLEY DAVIDSON FLHCS Heritage Classic HARLEY DAVIDSON FLHR Road King2018-2023 HARLEY DAVIDSON FLHRXS Road King Special2018-2022 HARLEY DAVIDSON FLHT Electra Glide Standard2017-2019 HARLEY DAVIDSON FLHTCU Electra Glide Ultra Classic2017-2023 HARLEY DAVIDSON FLHTCUTG Tri Glide Ultra2017-2023 HARLEY DAVIDSON FLHTK Ultra Limited2017-2019 HARLEY DAVIDSON FLHTKL Ultra Limited Low2017-2023 HARLEY DAVIDSON FLHX Street Glide2017-2023 HARLEY DAVIDSON FLHXS Street Glide Special2017-2023 HARLEY DAVIDSON FLRT Freewheeler2018-2022 HARLEY DAVIDSON FLSB Sport Glide2018-2021 HARLEY DAVIDSON FLSL Softail Slim2020-2023 HARLEY DAVIDSON FLTRK Road Glide Limited2023-2023 HARLEY DAVIDSON FLTRT Road Glide 32017-2019 HARLEY DAVIDSON FLTRU Road Glide Ultra2017-2023 HARLEY DAVIDSON FLTRX Road Glide2017-2023 HARLEY DAVIDSON FLTRXS Road Glide Special2018-2020 HARLEY DAVIDSON FXBB Street Bob2021-2023 HARLEY DAVIDSON FXBBS Street Bob HARLEY DAVIDSON FXBR Breakout HARLEY DAVIDSON FXBRS Breakout HARLEY DAVIDSON FXFB Fat Bob2018-2023 HARLEY DAVIDSON FXFBS Fat Bob HARLEY DAVIDSON FXLR Low Rider2020-2021 HARLEY DAVIDSON FXLRS Low Rider S HARLEY DAVIDSON FXLRS Low Rider S HARLEY DAVIDSON FXST Softail Standard 107

Product Grade: Performance Part


Brand: K&N


Fit Type: Vehicle Specific Fit


Product Dimensions: 12"L x 9.5"W x 4.88"H


OEM Part Number: RK-3956


Brand Name: K&N


Model Number: RK-3956


OEM Equivalent Part Number: RK-3956


Manufacturer Part Number: RK-3956


Global Trade Identification Number: 94


Manufacturer: K&N Engineering


UPC: 024844364494


Unit Count: 1.0 Count


Included Components: 1 Air Filter


Item Type Name: Intake System for Harley Davidson


Manufacturer Warranty Description: 3 Months


Item Weight: 4.04 Pounds


Item Dimensions L x W x H: 12"L x 9.5"W x 4.88"H


Shape: Oval


Product Grade: Performance Part


Fit Type: Vehicle Specific Fit


Automotive Fit Type: Vehicle Specific Fit


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Thursday, Jun 25

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Similar Products

Top Amazon Reviews

    • Beast filter kit! Beast filter kit!
Review Image by Big Mike
Review Image by Big Mike
Review Image by Big Mike
This is very easy to install. Directions are in color. They are a little vague but anyone with common sense can figure it out. I have a 2019 Road Glide Special with a 114 ci motor. The air filter kit fitment was on point and excellent fit. The one thing you need to remember is to install the 2 long spacers to the new back plate before you apply the new back plate to the bike. These will have inner threads on both sides. One side to connect to back plate and the other side to use to hold filter. On my specific bike/year/model I did not need the 1/4 inch thick silver looking spacers. At least I think they were 1/4 inch. I could be wrong with thickness. Now on power and torque. I noticed a huge difference in Hp and torque. This kit woke my bike up! Plus it sounds a little bit louder coming out of my Rhinehart 4.5" slip on exhaust. I can't wait to see how much better she will run when I get her dyno tuned in a couple months. Now as for hitting my knee...... Well I'm 6'4" tall and the filter lines up with my calve instead of my knee. I didn't notice any difference from OEM kit as far as my calve hitting the new filter kit. I never hit it at all. Shorter people shouldn't have any problem at all. Now onto what I don't like about this air filter kit. This kit does not use any hoses for the oil return into intake . It's design is the return goes through pre drilled holes that go back through intake. This design is awesome but if you want to install a catch can or reroute that oil to dump out into a filter instead of it going back into the intake. You won't be able to do that unless you really know what you are doing or find a mechanic who can fabricate new holes to run outside of intake and plug the original holes that run into the intake. There is a guy on YouTube who did it with his trask air filter kit that had the same problem. Anyways, that means I have work in the future if I want my oil burps to go to a catch can instead of returning to the intake. So if you are planning on installing a catch can of some sort then this might not be the filter for you unless you are a mechanic or an imaginative fabricator. Next is I cannot find a sock that fits this air filter kit or a sock that is specifically made for this filter kit. I wish or hope that kn comes out with a sock for this specific kit. Also if you find a good sock please leave it in your reviews of the brand and where you got it so the rest of us can possibly purchase one for this kit. All in all I love the look and love the design. If it came with a sock and a catch can design, this would be the best filter on the market. ... show more
Reviewed in the United States on July 21, 2021 Reviewed in the United States on July 21, 2021 by Big Mike
    • Great Intake, but…
This was super easy to install, and it performed extremely well. As others have stated, it does push my leg out to a slightly uncomfortable position, not a HUGE deal though. Unfortunately, I had to return it. The breather bolts provided eliminate the hose which routs the oil blowback out of the intake, which results in a mixture of water and oil gunked up all over the bolts. This isn’t the intakes fault, it’s a design flaw. I had to create an external breather system on the stock intake so I wouldn’t have old oil being shot back into the intake. ... show more
Reviewed in the United States on January 3, 2022 by Zack
    • Immediate boost in exhaust note and throttle response Immediate boost in exhaust note and throttle response
Review Image by Mattew D.
I wasted $280 not getting this to begin with! I started with a K&N filter to replace OEM, then went to the Screaming eagle hi flow (basically just removes the black box around the air cleaner) and now i have this. Of the 3 this filter provided the most obvious and immediate improvement. The filter does stick out a little like others have stated, but another inch or two on the brake side floorboard and you're fine (plan on getting floor board extensions when I install a new exhaust anyway) My exhuast IMMEDIATELY got deeper and throatier on first start up post install, the throttle response is AMAZING now. Gas mileage-wise the tune I used for the screaming eagle filter is still good (Harley SE tuner state I canned map and an auto tune run of 15 mins/10miles). Overall DEFINITELY recommend, you CANNOT find anything for the M8 in my opinion that will provide as much bang for the buck.....If you told me I could pay $100 to increase my exhaust note and $100 to increase my throttle response, I'd do it in a heartbeat, if you're considering it....DO IT! ALSO, I think it looks BAD A$$ gives the harley a kind of muscle car look with how huge the cleaner is. ... show more
Reviewed in the United States on January 24, 2020 Reviewed in the United States on January 24, 2020 by Mattew D.
    • Looks great! Looks great!
Review Image by TH
Looks great on the bike, one small complaint is that my leg touches this intake. This sucker has a habit of getting a little warm too. Time will tell if I leave it on or try a different version. But it does look great and sounds great too.
Reviewed in the United States on August 31, 2018 Reviewed in the United States on August 31, 2018 by TH
    • Nice item
Perfect fit
Reviewed in the United States on June 2, 2025 by brian rhodes
    • You're leg will rub a little but it doesn't bother me
Awesome very easy to install looks great on my 18 Heritage Classic 114 and made a,world of difference in sound and performance definitely recommend it
Reviewed in the United States on March 23, 2026 by Brian Gebert
    • Your engine will love you. Your engine will love you.
Review Image by Vormund
Fairly easy to install. Use the provided lock tite, as with any other part on a big twin. Looks good, gets plenty of air from all around, reusable filter. Have been using K&N for decades and they've never let me down. I've put 500 miles on the bike and have had no problems so far. It does stick out a little further than the stock air cleaner, but not enough to bother me. ... show more
Reviewed in the United States on April 26, 2021 Reviewed in the United States on April 26, 2021 by Vormund
    • Felt the difference immediately. Great upgrade! Felt the difference immediately. Great upgrade!
Review Image by Christopher
Easy to install and the throttle response from my other after market air cleaner to this on is night and day difference. Well worth the upgrade for the Milwaukee 8 motor. *retune is highly recommended and is truly worth it*
Reviewed in the United States on February 17, 2021 Reviewed in the United States on February 17, 2021 by Christopher

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