2005 YZ Forks vs. 2006+ YZ Fork Lower Tube Swap

I have a set of AOSS forks (read: 2005 YZ Kayaba forks) for my Husqvarna 125 that I'd like to swap for SSS (2006+ YZ Kayaba forks). I can't simply swap the forks themselves because of brake caliper mount/wheel geometry fitment issues.

 

To avoid those fitment issues, I could keep the lower fork tube from the AOSS forks, and use the internals and upper tube from the SSS forks. Has anyone tried this? Are the lower tubes from the AOSS and SSS interchangable?

Are the lower tubes from the AOSS and SSS interchangable?

 

May be almost OK. But, here are two elements that can be a problem.

At first, you need to compare the length of the cartridge of SSS with AOSS. If SSS is longer than AOSS, you can't use it.

 

And the other,

 

ctl_zpsc9d1a837.jpg

 

Right one is bottom end of the cartridge. Left one is a bottom cone that is built into the inner tube assembly.

These combinations are important. You must compare the diameter of cartridge end of AOSS with SSS.

 

If the part of SSS is larger than AOSS, the combination SSS cartridge and AOSS bottom cone can't work, specifically can't bottom, or crash themselves.

To solve the problem, you need to exchange SSS bottom cones too.

In that case, you need apart both fork lugs from inner tubes. And, that work requires special tools and machining.

Edited by kmtr

May be almost OK. But, here are two elements that can be a problem.

At first, you need to compare the length of the cartridge of SSS with AOSS. If SSS is longer than AOSS, you can't use it.

And the other,

Posted Image

Right one is bottom end of the cartridge. Left one is a bottom cone that is built into the inner tube assembly.

These combinations are important. You must compare the diameter of cartridge end of AOSS with SSS.

If the part of SSS is larger than AOSS, the combination SSS cartridge and AOSS bottom cone can't work, specifically can't bottom, or crash themselves.

To solve the problem, you need to exchange SSS bottom cones too.

In that case, you need apart both fork lugs from inner tubes. And, that work requires special tools and machining.

Good info. I'll keep that in mind.

I'll let everyone know what happens, but unfortunately the only way I can find out is if I bite the bullet and buy some SSS forks.

Good info. I'll keep that in mind.

I'll let everyone know what happens, but unfortunately the only way I can find out is if I bite the bullet and buy some SSS forks.

 

08+ SSS cartridges were shortened, and  bottom cones were changed their combined methods with innertubes.

SSS forks for 06-07 2strokes and 06 4strokes have possibility of compatibility with AOSS about this problem.

I'ill confirm them even on this weekend if you don't hurry. It sounds interesting.

 

But ,there is a problem. My AOSS forks for 05 YZ are in the most deep part of the garage.

It will be more difficult to excavate them than aparting themselves. :excuseme: .

Edited by kmtr

It won't work, not by a long shot.  Spring placement is way different on each one, bottoming systems are different.  Not worth the time.

 

The caliper is easier to figure out with an adapter, and the newer forks will go into the older triples just fine.  Your wheel will be off center maybe 1mm.  The casing of your tire has more variance in it than that when it spins, so don't worry about it

It won't work, not by a long shot.  Spring placement is way different on each one, bottoming systems are different.  Not worth the time.

 

Exactly. I confirmed AOSS forks right now. The problem is just GHILL28 pointed out.

The bottom cones of AOSS inner tube has about 4 inch long sleeve that serves as a spring retainer. There is no compatibility with SSS inner tubes.

The fork lug of AOSS seems to be transplantable to SSS inner tubes. But, to devise AOSS caliper will far easier than it. 

 

Sorry to be confused.

Pics?

I might open up my Husky fork to see if it looks like my old YZs SSS forks. I've been hearing conflicting reports about whether they resemble the 05 YZ (AOSS) or 06+ SSS.

Pics?

I might open up my Husky fork to see if it looks like my old YZs SSS forks. I've been hearing conflicting reports about whether they resemble the 05 YZ (AOSS) or 06+ SSS.

 

A basic question comes to me.  Are your 2012 Husqvarna CR forks really AOSS?

 

The KYB parts catalogue in my hand shows that 10-13Husq CR use some peculiar parts to SSS.

Compression Piston, Rebound Piston, Base Valve Compression, Base Valve Rebound, Free Piston Comp, Cylinder Head.

All of them for 10-13 Husq CR are same with SSS fork for YZ. They can't work on 05YZ AOSS.  Forks of Husq CR seem to be different from AOSS forks of 05YZ at least.

I'll show you pics of 05YZ AOSS cartridge tomorrow.

Edited by kmtr

I hear you. That's why I want to take a look myself since I've been into the SSS fork before. Never touched the 05 fork though.

This is a half aparting state of AOSS for 05YZ and SSS for 06YZ.

 

AOSS_zpsddca4b1f.jpg

 

The left one is AOSS. The right one is SSS.

 

The spring of AOSS is exposed in this state. The defference of spring legth is about 10mm.

This is a half aparting state of AOSS for 05YZ and SSS for 06YZ.

Posted Image

The left one is AOSS. The right one is SSS.

The spring of AOSS is exposed in this state. The defference of spring legth is about 10mm.

Awesome stuff! Thanks so much.

I called a few suspension shops who told me my husky spring and SSS spring are the same part number as are a few other parts, but the damping rod is different. So it sounds like the husky internals are compatible with SSS, but interchangable? I don't know.

I want to measure damping rods to compare between SSS and husky.

It may still be possible to swap only the SSS internals.

Measuring the innertube length from foot to top of slider, on the inside and outside of the tube would also be useful.

And the overall length of the fully extended and collapsed internals, for damping adjuster to fork tube cap.

Man I wish I had a set of the SSS forks to compare to.

Awesome stuff! Thanks so much.

I called a few suspension shops who told me my husky spring and SSS spring are the same part number as are a few other parts, but the damping rod is different. So it sounds like the husky internals are compatible with SSS, but interchangable? I don't know.

I want to measure damping rods to compare between SSS and husky.

 

OK. The length of damping rod from KYB genuine prats catalogue.

 

Husq CR: 394.0mm

06-07 YZ: 416.0mm

08-13 YZ: 397.0mm

 

The diffrence with 06-07 YZ and 08-13 YZ is connected with the change of the bottom cone and the fork lug. Those structure changes shortened length of 08-13 inner tubes and cartridge cylinders.

Probably Husq will be same generation with 08-13 YZ. They have compatible possibilities than 06-07.

I'll measur the cartridge cylinder and  the inner tube length of 08 YZ tomorrow.

Edited by kmtr

OK. The length of damping rod from KYB genuine prats catalogue.

 

Husq CR: 394.0mm

06-07 YZ: 416.0mm

08-13 YZ: 397.0mm

 

The diffrence with 06-07 YZ and 08-13 YZ is connected with the change of the bottom cone and the fork lug. Those structure changes shortened length of 08-13 inner tubes and cartridge cylinders.

Probably Husq will be same generation with 08-13 YZ. They have compatible possibilities than 06-07.

I'll measur the cartridge cylinder and  the inner tube length of 08 YZ tomorrow.

 

 

Cool - I think I'll be able to tear into my forks this saturday.

 I measured them.

 

At first, the cilynder length.

 

LC01_zpsb7f35c76.jpg

 

Its bottom end to under the under edge of the top cap is 612mm. But 592mm that the bottom end to the end of the step with the thread is more important one.

The end of the step and the top of the inner tube come into contact with each other and limit the bottom of the stroke finally.

 

Next, the length of the inner tube. But it's not measured at outside.

 

LIT01_zps3d663cdf.jpg

 

From top end of the tube to inside bottom end. It's 604mm. That is, there is gap of 6mm at bottoming.

 

Because the oil lock system works strongly, it is really rare that they come into contact with each other at the top end and the step..

But, this 6mm is the margin in the design of SSS by KYB.

 

The rest of the story, I'll talk about it after you measur them. :)

Edited by kmtr

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