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View Full Version : Any Cat suspension Guru's out there?



pauly
10-30-2009, 01:10 AM
Been riding cats for about 25 years. With an engineering background, I am pretty confident I understand how the suspensions work on sleds. Read several articles, that only confirm my thoughts. (Typically very basic of course)
My last sled was a 2000 ZR 600. Now I have a 06 T660 ST.
Same chassis. WHY ARE THE REAR SPRINGS SO DAMN STIFF?
I am a trail rider.. but like a sporty sled.
After all the adjustments I could make on the ZR, I got it so it was decent..would prefer softer, but O.K.. that and about 6000 miles to loosen the springs made it about perfect.
Now with my t660, it is much worse. The front (rear) spring is set as loose as it goes. The rear torsion springs are on lightest setting.
I did move the lower coupler link forward one bolt hole (as well as it's forward stop.) I weight about 180 and I can get on it, without the suspension compressing.. AT ALL. I stand on the bumper throw my weight up and down on it, and the lower coupler link, doesn't touch the coupler blocks.( I took video of it while doing this) When riding.. I am sure I am only using the top 4" of the 12" it comes with.

I haven't bottomed it out in 1000 miles of riding yet. If set up properly, and on a rough trail I would expect to bottom out every once and while, on that "spine bender" we all have been over??

I have already, moved the spring sliders for the torsion springs back about 4" to another hole. (which decreases preload) and bought the shorter plastic slides, decreasing preload(Cut off extra spring length). STILL too stiff.
I then looked up my springs, and the springs on a T660 touring (2 up model) My springs description says (HVY) at the end of the description.
The touring springs.. don't say standard info. SO I bought a set.
After I got original springs off I compared the 2. The wire diameter is the same, the free positions are the same, both are very magnetic (Thought one might be stainless) There IS one difference. The touring springs have 1 less coil. Which tells me, less spring, length, more stress.. stiffer spring.
I put them on anyway. I can't tell the difference. I haven't ridden it yet.. but still way too stiff. I cut them off as well and repositioned the sliders from factory position to 4" rearward position. With this change, the suspension maybe compresses an 1 or so getting on it. (Track loosened to decrease friction affect)
Does every sport rider, ride bad trails and weigh 275?

I am going to try stiffening my ski shocks a little to transfer some weight, but I don't feel this will make that big of difference.

Any thoughts on this? Does everyone just ride it this way?

Sorry for the book..
Can send pictures if more description is needed to help me solve this.
Thanks in advance,
Paul

pauly
10-30-2009, 06:21 PM
ttt

snoluver1
10-30-2009, 06:56 PM
What kind of shocks you got on this thing. You sure its the springs that are that stiff and not the shocks holding the springs up? Sounds to me like re-valving is in order. But then, I'm no engineer!

stealthv
10-30-2009, 07:00 PM
Have you had the skid out and/or skid shocks off? Sounds like the geometry is screwed up on the shock linkage which is very easy to do during reassembly.

mjkaliszak
10-30-2009, 07:22 PM
Could something be froze up or too tight on the skid ? Not pivoting or like above.. wrong geometry ? I had an old cat skid that I pulled out 1 time and just about went crazy trying to compress it enough to get it in and line up. I took it to someone that was " more familiar " with skids than my engineering self and we found out that the rear shock arm was not pivoting correctly. It was bound up. I had THAT SLED FOR 11 YEARS, painted the skid purple,put 3 sets of 288 studs in the track, modified the thing, had it in & out so many times that I don't care to admit.It was a humble day....

pauly
10-31-2009, 05:51 AM
Shocks are stock Fox Zero's,(all around)
I wouldn't think they should need a rebuild (revalve) but a option I haven't thought of.. Thanks

I had the skid out a month ago, Cleaned all greased joints, and relubed thoroughly. The suspension seems to act very normal with the rear torsions not in place. It is just as stiff before I made the changes as it is now..
I too have overhauled about 4 different suspensions. (some twice).

The shocks when operated alone do feel like they have some thick oil in them. Might have to yank those out and get them rebuilt - revalved...

THanks for the ideas guys!

favoritos
10-31-2009, 11:33 AM
This may help.

http://www.snowmobileshocks.com/

Give them a call.

speedbugy711
10-31-2009, 07:54 PM
one of my best freinds bought a new F-1000 with these shocks on it front and back and the beast is the stiffest suspention he and i have ever ridden!!! up front no sway bar and 12psi... out back lowest (softest) spring settings and coupler blocks setting... after all that it is just ok... hope this helps

Speedbugy711

snoluver1
10-31-2009, 08:36 PM
Pauly,
Not sure you quite get what I'm saying. I'm not saying your shocks need to be "rebuilt" due to being worn out. I am saying you can get your shocks revalved for your riding style, meaning they can make the shock softer or stiffer at different points through out the shocks travel. If you want a soft cushy ride at the top(for trail riding), any good shock rebuilder can do that for you. If you want it stiff as a 2x4(for jumping/agressive), they can do that to. Falling rate, progressive rate, what ever you want.

pauly
10-31-2009, 10:52 PM
Snoluver, I guess I understood what revalving would do.. but I had no idea they would affect the suspension that much.

Had I known, this, i would have taken out the rear shock and jumped on it with just the springs.. so I could see how much the shocks are contributing...

I should have asked this before the suspension came out.. and brought it back up north for winter...

Also, good to know I am not the only one with this problem.
Will also check out that snowmobile shocks link.

So it would be safe to assume that a 06 2 UP touring T660, probably has different shocks, or at least valved different?
They may still use hydraulics in the 2-up's... I'll look it up.
The reason I say this, is my uncle has a 06 2-up.. and it rode really nice. I know there is extra mass behind you that helps.. but this was night and day between mine and his..

Thanks much guys for the suggestions!