DK Custom Products

Phone: 662.252.8828
Text: 662.420.4891
Email: [email protected]

Differences Between Outlaw HiFlow Air Cleaner Systems

Differences Between

425 - 587- 606 - 636v


(See All the Dyno Charts Below)



First, let’s talk about what is the same about the Four Different Outlaw Model A/C Systems:

  • Made in The USA by DK Custom Products

  • All use a K&N Filter Element with a Million Mile Warranty

  • All Flow more air than the Sportster & Twin Cam  Motors can breathe*

  • All come with an External Breather System (EBS) for Optimum Performance, Stable Tunes & Extended Engine Longevity

  • Unique low-profile backplate design make the 425, 587 & 606 the lowest profile A/C’s on the market

  • Easy Installation

  • Street Developed & Tested -Dyno Proven

*Except the 425 on Twin Cams at high RPM, see more info below, does not fit the M8



The 425 filter element  is 4 ¼” in diameter and 2” deep, making it the second lowest profile air cleaner on the market.

There are 4 Different Cover Styles for the 425.

The Outlaw 425 flows more air than the Sportster can breathe, even a 1250.  

The Outlaw 425 is a bit too small for higher RPM riding on the Twin Cams.  It does great up until about 4500 rpm. After 4500 rpm it does not flow enough air for the 96 & 103 Twin Cam for them to develop maximum power.  It still runs fine, just not quite as strong as it could.

Many still like it on the Twin Cam because of the low profile, and because many folks don't run up past 4500 rpm.



The 587 filter element is 5 ⅞” in diameter and 1 ⅞” deep, making The Outlaw 587 the lowest profile A/C on the market.

There are 23 different Cover Styles for the 587, plus many stock and aftermarket covers will fit on it.

The Outlaw 587 flows more air than the Sportster can breathe, even a built 1250 running up to 7000 RPM.

The 587 flows very well for the Twin Cam & M8.  There is no point that even a 110 Twin Cam or 114 M8 can breathe more air than the 587 will flow.  This is a favorite because of the excellent leg clearance and superior airflow. There is a huge selection of different looks for this air cleaner.






The 606 filter element is 6” in diameter at the back, 5 ½” diameter at the front,  and 2 ¼” deep, making The Outlaw 606 the third lowest profile A/C on the market.

The Outlaw 606 sticks out 3/8" further than the 587, but it is still quite a bit more tucked in than the stock air more than an inch.

There are 8 different Cover Styles for the 606, including running naked, with no cover.  Very Importantly, the 606 was designed to work with the Stock Rushmore Cover & the Stock Milwaukee-Eight Cover.  It bolts right on, as do many other stock and aftermarket covers.

It has very similar flow characteristics of the 587.  The 606 will flow more air than any Sportster, Twin Cam, or M8 can breathe.  

The 587 and the 606 dyno out almost exactly the same...the reason we came up with the 606 was for a different type of cover fitment, including the OEM Rushmore Cover & OEM M8 Cover.






The  636v is a forward facing Air Cleaner.  You have a choice of five different air filter elements.

All covers that fit on the Heavy Breather, including the SE designs, will fit on the 636v with the round style filter element.

The Outlaw 636v is effectively low profile also, since it puts the filter so far forward.  So even though it sticks out further than the 425, 587 and the 606 by a bit more, it does not interfere with the leg.  

The patented design generates a Venturi Effect that  gives the Outlaw HiFlow 636v Air Cleaner an Increase in Intake Velocity producing 3-6% more power than the 425, 587 or 606.  It will also flow enough air for even a fully built out 140 cubic inch engine.


 Milwaukee-Eight Dyno Charts




Twin Cam Dyno Charts



Bonus Chart- Showing what a Monster the 636v Air Cleaner is!


Sportster Dyno Charts







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