KTM, GasGas, Husqvarna Spring Fork KYB Conversion Kit $250 Shipped

Thanks.  It started as a project in the shop to help out a few buddies and turned into something we all really liked.

There's no exact answer to total fork length since it depends on the cartridge length and conversion kit you choose.  I've added some detail below and bolded the most important text so you don't have to read through everything if you don't want to.

WP21KKIT-L Adds 14mm between your cartridge rod and your axle when installed in a 2021+ WP fork lug
WP21KKIT-S Adds 24mm between your cartridge rod and your axle when installed in a 2021+ WP fork lug

My rebound adjusters have 15mm deep threaded engagement on the rebound rod to match the OE KYB rebound adjusters.  They also offer the same amount of rebound adjustment per click and the total range should be within about a click or two depending on manufacturing tolerances in my parts and the KYB parts you use.

I will make up a graphic showing these measurements and add it to my technical information section on the site.

More detail below:

My terminology "Long KYB Cartridge" and "Short KYB Cartridge" are generalizations, but a look through the KYB parts catalog and measuring cartridge components shows that there are multiple different lengths of rods, top-out springs, mid-valve posts and other important components.

An example of what I believe is the best performing configuration is the 2018+ YZ450F and 2019+ YZ250F KYB cartridge using my kit for the "Long KYB Cartridge"  WP21KKIT-L     Those Yamaha cartridges are approximately 932mm to 933mm long to the end of the cartridge rod, or 917mm long to the top of the rebound adjuster.   My "Long KYB Cartridge" kits measure 29mm from the top of the rebound adjuster to the axle centerline, or 14mm from the end of the cartridge rod to the axle centerline.   This gives you a length from the bottom of the KYB cap to the axle centerline of approximately 946mm to 947mm. 

Spring rate and preload will have a minor impact on cartridge length and in turn, fork length.  
A lot of preload on a stiff main spring will slightly compress the top-out spring, making the cartridge slightly longer, sometimes as much as one or two millimeters.

The other kit I offer WP21KKIT-S is 10mm longer to make up for the shorter KYB cartridge from older Yamahas and perhaps other applications.   Those kits measure 39mm from the top of the rebound adjuster to the axle centerline, or 24mm from the end of the cartridge rod to the axle centerline.

My goal with the kits was to get people within a few millimeters of a standard WP fork length.  This allows fine adjustment of the front end ride height using the fork height in the triple clamps.  

Hopefully that helps to answer your question. 
Let me know if you want me to elaborate on anything specific and I'll do my best to get you accurate information.

I've added the following to the Technical Information section on the site.

I don't think my kit will fit the cone valve fork lugs.  It is designed specifically for 2021+ WP XACT air fork lugs.   
Also, I believe the cone valve upper tubes are not compatible with KYB cartridges due to a different thread pitch at the cap.

I haven't worked on a lot of WP cone valve forks, but all of the sets I have seen use a completely different fork lug and outer tube system.

I've pulled the cones and cone adapters out of an older set of CV forks and replaced them with shims in the past for a buddy.  I would guess GoggleFiend904's suggestion for the JBI kit would be a cleaner way to do the same that comes with tuning advice.

Yes, the 2021+ WP air forks are what my kits are designed to work with.
The adapters will drop right in without removing the fork lugs.

 

Thanks, that's helpful information as I haven't measured any Honda KYB cartridges yet.

I think the Honda parts are a viable option for Husqvarna owners.
 

Theoretically it should be very close to the standard preload spec of a Honda, within 1mm or 2mm if you run OEM springs.
Many aftermarket springs are shorter than stock (RaceTech, etc) so they can be used in multiple models and set from zero to any preload value using preload shims.

With the 2020 YZ250F cartridge I gave as an example above, I get 5mm or 6mm preload with OEM Yamaha springs.   

The 2012 KX450F cartridges in my GasGas would end up about within 1mm of Kawasaki's stock setting, but I chose to set those up with YZ-F springs and some modified FC supercross style perches. I made sleeves to set the preload on the shortened perch. 

Pro Circuit offers a similar perch to the FC part and theirs are already cut down the way I modded mine.

Bumping this post and adding a link to the thread with technical discussion.

https://www.vitalmx.com/forums/moto-related/easier-kyb-spring-conversio…
 

Some KYB cartridges from older Yamaha applications require a modification to the cap. 
The photo below shows a set of cartridge tubes from a 2012 YZ250 (two stroke). 

The flange on the left is original size while the flange on the right is shown after being reduced by about 0.030" in diameter to fit through the top triple clamp on a KTM, Husqvarna or GasGas.   The original Yamaha diameter is 2.151" (54.8mm) and the modified diameter matches the WP XACT 48 air fork cartridge which is 2.121" (53.8mm).

This modification takes a few minutes to perform on a small lathe, but I offer it free of charge with your conversion kit purchase.

Based on conversations I've had with customers, a lot of people are buying a complete set of forks from private sellers on Vital, eBay, MXLocker, etc.  I have bought forks from all three of those places for R&D in the past.

Some guys sell off their stock forks or cartridges when they upgrade to kit forks or Ohlins internals.
There are a few guys around here (also on the auction sites) who break up new and used bikes and part them out.

Lots of suspension shops can also get new cartridges through Technical Touch USA and set them up for you.
You can buy new fork cartridges from the OEM parts retailers, but those are typically on the high end of the price range.

If you do buy a set of new or used forks, rather than bare cartridges, you get springs and spring perches with them too.  That can be useful for guys who are within the intended weight, speed and bike size of those donor forks.

Feel free to ask any application specific questions you have on the forum or via e-mail before you buy some donor forks or cartridges.  I'll do my best to get you the information you need to make a good decision on parts.

Since nobody replied yet, I'll give my opinion:

Compared to the standard valving on XACT forks, most people notice reduced sting on slapper landings with any KYB spring conversion.   Faster guys tend to notice that the bike responds better to small bumps and square edges on jump faces, jump landings and G-outs while offering more hold up in those areas.    It all depends on spring rate, valving and oil height.

I have my own shim stacks and settings for the older 24mm KYB cartridges that I can share with the guys who valve their own stuff.  I'm currently running them in several of my friends' bikes as well as my own MC350F.

On the Austrian four strokes, the 25mm KYB cartridges from a 2018/2019 and later YZ450F/YZ250F are a great starting point for Motocross starting at about nine or ten clicks on both compression and rebound.   You gain a lot of front tire traction once the clickers are dialed in for bike/track/rider.

So far, everyone I've worked with locally and customers who've sent me feedback have landed somewhere between 325cc and 360cc oil volume in their conversions.

I think the spring conversions are really only worth it for a Novice or better rider who has an idea what they want.  For a beginner level rider the standard XACT air forks are pretty damn good if they check air pressure each ride day.
 

I have another production run of the 2021+ conversion kits on the CNC machines right now with a few left in stock.

The 2016.5 - 2020 AER-48 fork conversions will be coming up next on the machines and added to the website with details soon.
 

These conversion kits, fork cap wrenches and shock adjuster tools have been restocked at   dialedmfg.com

I hope to have the new kits for the older 2016.5 to 2020 AER-48 forks up on the website by Monday, August 5th.

As far as I'm aware, Enzo still uses the Technical Touch kit like many other tuners.

I'm sure there are people who have a strong opinion on what you feel from changing fork lugs, but I'm not one of them and I can't really say one or the other is superior.   I have ridden both, but never with identical valving on the same day.  That would be the only legitimate way to test.

My gut feeling is that the billet lugs would be a stiffer and heavier part, but I doubt I would or could feel any difference in a true back to back test.  
I'm a mid-pack guy in the local 40A class, so I'm not pushing the bike to the limit like a younger pro level racer.

In my opinion, the real difference in ride feel is going to be in valving and spring rates.   A well tuned KYB conversion should give you more comfort combined with more hold-up and confidence to ride the bike harder when you compare it to the production WP air fork.  Even with stock valving, the KYB cartridges from a 2019+ YZ250F feel better for most riders when installed in a KTM chassis with the appropriate spring rates.

The primary advantage to my kit is that almost anyone can drop in a set of KYB springs and cartridges at home and improve their bike, then return the bike to the stock configuration when it's time to upgrade to a new model.  In most cases the KYB conversion can be brought forward to the next bike.

You can also send the kit and parts or assembled forks to any suspension tuner to have them set up the valving for your terrain, weight and speed since they are standard KYB components that everyone already knows how to work with.

A second advantage is that you can choose to run 24mm or 25mm cartridges if you have a preference.  

The disadvantage to my kits and business model is that I don't offer a revalving service and you have to source your own KYB donor forks or cartridges (new or used).

I do valving and setup on my bikes and for some local guys, so I'm always willing to discuss that stuff via e-mail sales@dialedmfg.com or to share what I run in my own bikes and what I have tried in other bikes I've worked on.  I use some software that simulates shim stack behavior to generate damping force curves, etc.
 

The kits for the 2016 - 2020 KTM and Husqvarna models with WP AER-48 forks are now available, also for $250 shipped.
Just like the kits for the WP XACT air forks, the standard WP AER-48 fork lugs are retained, but these older AER-48 forks require the lugs to be removed as part of the installation process.  The existing WP oil lock (bottoming cup) must be removed and replaced with the Dialed Mfg spring perch and oil lock assembly.   New fork lug o-rings are included to ensure your fork lugs do not leak after the conversion.

https://dialedmfg.com/KYB-Conversion-20165--2020-KTM-Husqvarna-WP-AER-48_c_14.html

These AER-48 kits are available in the same two lengths as the XACT kits shown in the previous posts.

WP16KKIT-L


WP16KKIT-S

Thanks!  I just got back in from a mountain bike ride and I'm about to pack up your order.
Feel free to shoot me an e-mail or reach out on the forum if you do have any questions.
 

I'll be looking forward to hearing about your experience with all these different options.