Rear suspension

[01mndoo]

I have a 01 MXZ 700 with the Sc10 2. I stretched it out to a 136 using rail extensions from Mountain Machines this year and am having a problem with the rear suspension. When I push down on the back bumper I only get about 2-3 inches of travel and it just stops moving, The suspension does work when I am ridding but does not work as well as it used to when it was a 121. I have gone through the rear suspension twice and can not find anything that might be causing this problem, I am wondering if anyone else has had this problem and if anyone has any ideas how to deal with it.
Thanks

 

[jimfsr]

Look and see if the coupling blocks are hitting the stops at the same time you are running out of travel. If so, the suspension is binding up as it couples for some reason. The rail extentions shouldn't affect it. Is the track too tight? try putting a block about 4" thick under the front of the track and see if it changes anything. Do the same with the block at the back, and see if anything changes. loosen the track up a bunch and see if it changes. The longer track should be a little looser than the short track.

 

[01mndoo]

rear suspension

I want to know if I am getting this right. If the suspension is hitting the coupling blocks at the same time it is binding up somewhere? I took the bar that runs from the rear arm to the front one out as well as the rear shock and it still didn't want to drop. When I dropped the rear arm to see if it was locked up it folded up and down with no problems. I don't think the track is to tight because I can get a 1.5 to 2 inches of when I push down on it. Any ideas where it might be binding or and other ideas would be great.
Thanks

 

[jimfsr]

Try to find a picture of a renagade and see how it goes. I have a friend who just did the same thing (rail extension) on a 04 XPS edition and it was fine. Something in there is installed incorrectly.

If it seems to lock up when the stoppers hit the blocks, even w/o the shock and bars in there, The suspension cant swing up and back for some reason. The problen could be in the front shock and arm, does that one compress?

 

[doo_dr]

I have done many of these change out and you have to remember two things:
1 You are long tracking a trail suspension that is coupled. The suspension is designed to plant the skis back on the ground by loading the travel of the rear into the front of the sled. 2 When you add lenght behind the rear pivot point you are increasing the travel lenght in reference to the rear wheels of the skid. It is like adding a cheater bar to a rachet to break a lug nut loose. This means that your coupled suspension will react much differently in both ride height to stiffness.
That being said, if you have only a few inches of travel while pushing on you rear bumper and then it stops. Look at the transfer blocks. If they start touching the rear bump stops when your pushing on the rear bumper "All is good so far". If you have someone put all of thier wieght on the back bumper and you stand from the side, You should see the skis push forward and then the sled will totally bottom out. It is hard to put something in backwards on these suspensions and make them lock up. It is just going to feel different from your 121" Good luck!!

 

[01mndoo]

Update

Well when I got home I looked it over once again and still don't see anything that is mixed up. The only thing I did when I had it out was get the shocks rebuilt and add the extension so I don't think I put anything back in wrong. Tonight I put a 4x4 under the front arm and it did what it is suppose to do. The only thing i can think is it has to do with having to let the limiter strap out to compensate for the new front shocks and skis. As I said it works OK but wish I knew what was up.
Thanks

 

[01mndoo]

Update

Thought I would give anyone watching this post an update on what is going on. Today I brought it down to the local Ski-Doo dealer and had them check it out. The guy at the shop looked at it and had me jump up and down on it and said it all looks good. The only suggestion he gave was to rotate the coupling blocks so it would not couple as quick. I got it home and tried it out and it now works better then it did. I guess that is the way it is going to be. Thanks for the input.

 

[dakota]

you mentioned you had the shocks rebuilt while you had it apart. Could a heavier weight oil or higher pressure have been used? both will make the ride feel stiffer.

 

[01mndoo]

The dealer said they rebuilt them to the stock specs but that might be part of it. I had not had those shocks rebuilt in 8 years and 3500 miles. I think I might have been used to the sloppy way they were and now they work the way they should.

 

[fastcat800]

The dealer said they rebuilt them to the stock specs but that might be part of it. I had not had those shocks rebuilt in 8 years and 3500 miles. I think I might have been used to the sloppy way they were and now they work the way they should.

Exactly, the '91 MXZ shocks are preaty stiff. Thicker oil would slow your rebound down so the sled would squat under aceleration until you let off of he gas and HPG's take 300 psi which is usually the max peressure on fill valve regulators.