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Air and Fuel› Air Cleaners, Filters, Intakes and Components

K&N

High-Flow Air Intake System

$329.99 $299.99 Save $30.00

SKU: RK-3944

In Stock
In Stock
Ships by Sep 13
Free Shipping over $200
$100 Minimum Order
30 Days Return
INSTALL DIFFICULTY
DIY PRO SHOP

Easy — 1–2 hours

Overview

The K&N RK-3944 is a high-flow air intake system designed for Harley-Davidson Sportster motorcycles from 2004-2013. This system features a custom aluminum backing plate that bolts directly to the throttle body and includes a built-in breather system.
Show original supplier description
The K&N Street Metal Series High-Flow Air Intake System (RK-3944) is engineered to enhance the performance of select Harley-Davidson Sportster models from 2004-2013. This intake system replaces the stock air cleaner with a high-flow design, aiming to boost horsepower and torque. The system utilizes a custom aluminum backing plate that mounts directly to the throttle body, incorporating an internal-run breather system for a clean installation. A durable mounting gasket is included to help absorb vibrations. Key features include a red cotton gauze air filter with a height of 2.125 inches, a chrome top finish, and an estimated horsepower gain of 4.33 HP at 5596 RPM. The product also comes with a No-Hassle Lifetime Limited warranty. Fitment specifically includes various Harley Davidson Sportster models such as the XL1200C, XL1200R, XL883, XL883C, XL883L, XL883R, XL1200L, XL1200N, XL50, XL883N, XL1200X, XL883L SuperLow, and XL1200V Seventy-Two, covering model years from 2004 through 2013 (with some variations in end years).

Product descriptions are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.

Fitment

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Specifications

BrandK&N
Part NumberRK-3944
CategoryAir and Fuel

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Returns & Fitment

Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

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Shipping

Orders are processed in 1–3 business days. In stock parts ship promptly from our partner network. Special-order items either aren’t currently stocked or are built to your spec — expect 4–6 weeks. If a part goes on backorder while your order is in the queue, we’ll reach out and work through discounted alternatives together.

Free shipping over $200 in the continental US. Alaska, Hawaii, U.S. territories (Puerto Rico, U.S. Virgin Islands, Guam, American Samoa, and the Northern Mariana Islands), and international orders carry surcharges — most appear at checkout. Some exceptions (LTL freight, or suppliers who quote freight only after we place the order) won’t. In those cases we’ll reach out with the exact charge before your order moves forward.

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