DK Custom Products

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Complete Naked Stage I HiFlow 606 Air Cleaner System Sportster

Availability: In stock
Item #: DK-AC-606-NK-S
Manufacturer: DK Custom Products

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Harley Sportster HiFlow 606 Air cleaner DK Custom Nightster Iron 48 High Flow Harley Davidson Custom Low SuperLow naked performance air cleaner 606 intake kit Ness Big Sucker K&N EBS External Breather System Carbureted EFI Stage I

Outlaw HiFlow 606

Air Cleaner System


Sportster Models 1991-UP

~Complete High Performance System~

 ~Fits EFI & Carbureted~

MADE in The USA!

DK Custom Products



  • Tapered HiFlow Genuine K&N Air Filter
  • 6 1/4" Base & 5 1/2" Face Diameters 
  • Support & Backplate Black Powder Coat Finish
  • Naked- Plate Cover
  • External Breather System - EBS (NO dirty air in motor)
  • A True Stage I Air Cleaner
  • E-Z Step-by-Instructions Included
  • Made in The USA!


The Outlaw HiFlow 606 System will give your Sportster the Air it needs to Produce Maximum Power.  CLEAN AIR - No dirty air routed back in! 

This system is TURN-KEY.  It comes with everything needed to replace the restrictive stock air cleaner.

E-Z Installation with Step-by-Step Instructions.

Genuine K&N Filter with Million Mile Warranty.

Filter is re-usable.  Simply wash, let dry, & apply oil.

Fits Carbureted & EFI Sportsters 1991-Up.

This is a must for at Stage 1 Upgrade.


Included: Your Choice of Brass, Black or Polished Aluminum Breathers.  Or you can choose one of the Hose & filter Breather Systems for venting - The Traditional, the Discrete, or the Premium Discrete  To see full details on All these choices Click  HERE

When choosing between the 6 Breather systems, it is helpful to know-

 1.  All three Breather Bolt function the same, it is just a matter of which color you prefer.

 2.  All three of the Hose and Filter Breathers function the same with the Outlaw Air Cleaners, it is a matter of which system you like the looks of the best. 

The Transformer™ is the Ultimate External Breather System, that Doubles as a Support Bracket and can be Transformed into an EPA (Emissions) Compliant System. It fits all Outlaw Air Cleaners.

This 606 comes with no cover.  A cover is not needed, and you can run it this way, or let your imagination run wild and secure any cover you want to it via, the center bolt in the filter element.


Just about any HD or aftermarket cover (round, teardrop, etc.) will fit over it, or use a CD or make something.


You can upgrade to the Outlaw HiFlow 606 Air Cleaner System without doing any dyno work or adding tuners IF you leave the stock exhaust in place.

he EPA has required Harley to route dirty, oily crankcase air back into the air cleaner compromising the performance of your engine. The External Breather System vents it without compromising the performance or longevity of your motor.

Caution:  Motorcycles modified with this DK Custom Products High-Performance part may not be legal for public highway use in some areas.  The user shall determine suitability of this product for his or her use.

Check out the Dyno Chart!  21% increase when combined with the Thunder Torques.

"I dig your air cleaners cause it's such a great platform to personalize your bike.  And you can do something different on either side and just flip from one side to the other for a different look.-Bart

"Bike runs amazing with addition of this air intake and external breather..
I've bought many aftermarket parts for cars mx bikes. Nothing has ever come close to the difference this intake has made. And best customer service I have Ever experienced." -EK


Customer Reviews

For big twin Evo Review by Herb
I installed the air intake on my 1996 Softail. I had to email DK C a couple of times to figure out what I needed - support bracket, air intake, breather bolts, etc. I can never find the 80” Evo info on their page. But email works well.

For those of us who don’t like to read one page of instructions, the intake is easy to install and there are YouTube videos showing the correct steps anyhow.

Included external breather bolts. Good value. (Posted on 1/29/2024)
Pretty good Review by Matt
Switched from the HD stage 1 to run an external vent. My package was missing the gasket from the filter to cover which isn’t a huge deal but still. The instructions say that if the support bracket doesn’t sit against your heads then you will need a washer in between and none are included which i feel like they should be if it’s a known issue. Other than that it went together as expected and looks great. For the price these little touches i feel should be included, how much could an extra 2-4 washer be and a rubber gasket. (Posted on 10/3/2023)
Really like this Review by Shawn
The simplicity is excellent, DK is spot on with their products . I like the naked to customize the cover however I choose to . (Posted on 11/6/2022)

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