DK Custom Products

Phone: 662.252.8828
Text: 662.420.4891

Performance Stage I Kit for Twin Cam Models

Availability: In stock
Manufacturer: DK Custom Products

DK Custom Performance Stage I Kit for Twin Cams Harley-Davidson Dyna Softail Touring K&N air cleaner XiED Power Vision TTI Thunder Torque Insert


Dyna ~ Softail ~ Touring

DK Custom Products



  • Outlaw HiFlow Air Cleaner System
  • Enhanced Power & Sound from Current Exhaust
  • FP3 or Power Vision Flash Tuner w/ Auto Tune - Customized Map - Accessories & More
  • E-Z Installation


Package Discount ~ Save $50.00



STEP 1 - Choose Your Air Cleaner

The Outlaw Air Cleaners are some of the few Uncompromised High Performance A/C's still available. They come in a Wide variety of looks and designs.  The 425's, 587's & 636v's will all flow more air than your Twin Cam can use.  Click on 425, 587 or 636v & add your choice to the shopping cart in the new tab, then close that tab and return here to continue your order. 


Step 2 - Boost Your Exhaust Performance

The "W" Series Thunder Torque Inserts can be used with stock slip-on mufflers, or with almost any aftermarket slip-ons or full exhaust systems.  They will deepen the tone and increase the low & mid range power.  Click on this LINK & add your choice to the shopping cart in the new tab, then close that tab and return here to continue your order.

If you would like a Stage I Kit that Includes either Slip-ons or a Full Exhaust System, Click HERE.


Step 3 - Choose A Flash Tuner 

The Two Best Choices in Flash Tuners are the FP3 & the Power Vision.   They are both delivered to you ready to install, with a map for your bike.  You can plug it in, load the new tune into your bike, unplug it, and be riding with the New Tune in 5 minutes.  It's that simple for both of them.  

The FP3 is less expensive and a great choice for Stage I upgrades, and good for some Stage II upgrades.  

The Power Vision is a bit more expensive, but has every possible feature and will support all the way up to a Stage IV upgrade.

Click on this LINK to see all the FP3 Features.

Click on this LINK to see all the Power Vision Features.

Choose one of them & add it to the shopping cart in the new tab, then close that tab and return here to get your discounted price.


Step 4 - Use the Kit Discount Code

When ordering online, use this Code - PerfStage  - for a $50.00 Savings.  After you have completed steps 1-3 above, click on the SHOPPING CART button in the upper left of this screen, and use this Code - PerfStage  - while checking out for your Savings.

You can also call us at 662-252-8828 and Save over the phone.  Email inquiries should be directed to


Check out the Dyno Charts and photos at the top to see what benefits you will enjoy with a DK Custom Performance Stage I Kit Upgrade.


*If your Pre-2007 Twin Cam has a Carburetor, no Fuel Enrichment Device is needed.  Instead the carburetor will need to be re-jetted to get the most out of your Stage 1 upgrade.  We recommend getting a Jet Kit from DynoJet or CV-Performance. For carbed bikes, use this Code - BasicStageC - for a $15.00 Savings.


Caution:  Motorcycles modified with 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.



Overview of a Stage I

(Optional Reading for the Technically Curious)


Stage 1 Kits are comprised of 3 components:


  1. Free Flowing Air Cleaner
  2. Free Flowing Exhaust
  3. Fuel Management for EFI and Re-Jetting for Carb



With each of these 3 components there are sometimes a confusing number of choices.


1.  With Air Cleaners there are two basic performance choices, and an endless number of "Looks" to choose from.

The difference between most air cleaners and the DK Custom Outlaw A/C Systems is the Quality of the Air.

Performance Choice #1 - Unfortunately the EPA mandates has Harley-Davidson and almost every aftermarket air cleaner company pushing the blow-by into the air cleaner.  What comes out of the breathers is primarily exhaust gases and oil, it is also hot.   This is counter-productive to performance & engine longevity.  Harley engines perform better with cool dry air & gasoline, not hot, oily air and gas.  Additionally, the exhaust gas has a lower oxygen content, displacing oxygen on each combustion stroke.

This type of air cleaner is a poor performance choice.


Performance Choice #2 - The Best Performance Choice is an Air Cleaner System that allows only clean dry air into the intake.  

DK Custom Products Line of Outlaw Air Cleaner Systems are Air Cleaner Systems that utilize external breathers, allowing only Dry, Clean Oxygen rich Air into your intake.  

The DK Outlaw Line of Air Cleaner Systems has Many Looks to choose from.



2.  There are 3 main factors that are considered in upgrading exhaust:





There are dozens of companies making hundreds of different looks and levels of sound, and almost all claim big performance increases. You can see a LARGE Selection of Top Quality Slip-ons and Full Exhaust Systems HERE.

If you would like to keep your current exhaust system, improve its' performance, and to a smaller degree, the sound...

...we have a small component, Thunder Torque Inserts, that can be added to almost any exhaust slip-on or system.

The "W" Series Thunder Torque Inserts (TTI's) will slightly deepen the tone, and, more importantly, will increase the low and mid range power by 5%-20%, by reducing engine pumping loss, & increasing exhaust gas velocity.  The Patent Pending TTI's are literally the most power increase per $ spent of any mod that can be done to a Harley-Davidson motor!


Example of Some Different Exhausts with Thunder Torque Inserts Installed



The "Best" Exhaust is what YOU like the Looks and Sound of

The TTI's will Optimize Performance

If you would like to add Slip-ons or a Full Exhaust System, You can see the Stage I Kits with those by Clicking HERE.


3.  In the Fuel Management arena for EFI Harley's, there are dozens of choices.  Ranging from doing nothing to spending as much as $600, or more, for a tuner and dyno tuning.  

While it is possible for the modern Harley to run a free flowing air cleaner and free flowing exhaust without doing anything in the tuning/fuel managment arena, our experience has shown that it will run hotter than is good in the long term, AND, will not run nearly as well as it could.  

In the last 5 years HD has gotten leaner and leaner with the Air Fuel Ratio, causing more & more heat.  While the ECM will adjust for changes to a certain degree, they will never adjust past the "too lean" factory (EPA mandated) settings without the help of a Fuel Management Device.


Our experience with thousands of bikes has shown that the best economical choice is one of the XiED Products.  These are Plug-n-Play fuel enrichment devices that will give you 80% - 90% of the benefit of a Full Blown Tune for about 20% the cost.  

We have Thousands of Customers that are very happy with their cooler running, stronger accelerating Harley's as a result of using an XiED device.



In our experience, the next step up in tuning is an FP3.  It is an excellent flash tuner for late model Harleys.  While not as powerful as the Power Vision (see below), it works very well with stock Harleys, and Stage I (free flowing air cleaner & exhaust) bikes to deliver a tune that is MUCH stronger and cooler running that the stock tune.

It also comes with an Auto Tune feature that allows you to ride and get the tune dialed in for your specific set-up, riding style and environment.

The FP3 is also a ton of fun to use.  It interfaces and displays via your smartphone (iPhone or Android) making it super easy to use and display useful information.

The Fuel Pak FP3 is a very solid choice for Stage I Upgrades.



This same experience has shown that the Power Vision Flash Tuner can be used to achieve the best possible tune for performance, reliability and economy....  

...All without having to spend any money on Dyno tuning.  With the Power Vision you can choose to Dyno tune if you wish, but, since the Power Vision comes with a Customized Tune from us, plus an Auto-Tune Feature, the vast majority do not find it necessary.  


The Power Vision has the added benefit of several other features-

  • Touch Screen Control - No computer needed
  • Doubles as a Gauge Cluster, displaying your choice of info, up to 6 different read-outs in one screen
  • And many other features (and extras from us) that you can see HERE


Do not use the fields below to order, instead follow the instructions above in Steps 1-4 to place your order.

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