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97 mxz soft skid frame

2K views 28 replies 10 participants last post by  zr_580_1994 
#1 ·
Hello all.
I've been putting this sled back together for a while. It was a basket case when I got it. Now that I have things back in order and ready for a test run I find that the skid frame is very soft. I have put on a new rear shock and springs and there was little to no change. There is nothing binding. I sit on the machine (I'm 240 lbs) and it dam near bottoms out.
Any ideas as to what is going on?
Thanks
 
#7 ·
Right springs. Wish I had your problem chilly. I lift the back end up. Let go and it drops six inches and that with no seat. Get on it and snow flap hits the ground. Going to change front shock but I have my doughts it's going to change anything but it's the only think i haven't changed. No one has changed the mounting. Is it possible this 97 had a different skid under it from factory? Bolt to bolt c to c is 24 5/8
Thanks for response
 
#10 · (Edited by Moderator)
Do you have SC-10 or ??

Interesting reading I found about your problem

from http://www.ski-doo.com/Archives/english/archives_1998/98models/a_lab_03.html

SC-10 REAR SUSPENSIONS (Super Comfort 10" of travel)
Most Ski-Doo rear suspensions are created from this long-travel platform. Shocks, springs and other mechanicals are calibrated for comfort and performance in all types of riding.

Rising-Rate SC-10: High Performance, Cross Country variations
Used in performance applications, this version of the SC-10 provides the most absorption at the end of its travel, for optimum cushioning. It is also calibrated to sag about one-third of its travel length to provide a lower center of gravity in normal riding conditions. When it encounters a big bump, it expands, then uses all 10 inches to cushion the bump.

Falling-Rate SC-10: Sport, Touring and Mountain variations
Using geometry and components calibrated and designed to provide the most absorption at the beginning of its travel, this suspension cushions the moderate bumps in trail riding best.

ACM (Acceleration and Control Modulator)
The patented ACM on the SC-10 rising-rate rear suspension connects the actions of the rear arm to the front arm. It allows the suspension to absorb big bumps better by distributing the impact between both rear shocks and suspension arms. Riders can adjust the sled's mix of acceleration (ski lift) and cornering bite (ski-pressure) by turning a nut on the ACM. When adjusted for cornering, it causes the sled to sit flatter during acceleration, increasing ski pressure and control.

ARC Rear Suspension
New for 1998 and used exclusively on the Formula Z 670 model, the ARC is a fully-coupled rear suspension and is designed especially for aggressive trail riding. It uses one swingarm with two shocks mounted at the center of the suspension. Two control arms transmit bump energy from the front to the back and fice versa. This coupling action also controls weight transfer to improve handling qualities like balance and ski bite.

SC-10 High Performance LT with Pneumatic Leveler
Standard on the Grand Touring SE model, this driver-controlled suspension system uses pressurized air in the rear shock of the SC-10 High Performance LT to absorb the bumps. The driver can achieve the smoothest ride possible for conditions--soft or hard surfaces and varying driver, passenger and luggage weights--by increasing or decreasing the air pressure in the shock with the on-board air compressor at the flick of a console switch.

Direct Shock Action (DSA) Front Suspension

DSA is a trailing arm front suspension that comes in several variations and travel lengths depending on the application and shock choice. New for '98 on all CK3 machines is an unequal length radius rod configuration. Radius rods control the trailing arms' lateral movement during suspension action. The unequal length set-up flattens the travel arc for more precise ski camber and toe-in during suspension action, which makes for precise steering.
 
#12 ·
Yes it's a sc-10. Shocks and springs bought from royal (kimpex?). There was no change when installed. Seems like there is no up lift. Goes down and stays down with little left for suspention. Front shock replaced but did not replace coil. Great read. Maybe acm is the issue and needs to be adjusted? Checked my neighbours sled. Same sled and I know it needs shock and springs and it have more up lift than mine. Not sure what to make of it but it can't be ridden the way it is.
 
#13 ·
Hate to tell you but those kimpex shocks and springs are junk brand new. I found out the hard way also. Replaced everything and it wasn't any better than before. Gonna have to get some doo springs and try to find a hpg shock, I'd get some 2up springs also for your size.

Good luck.
 
#14 ·
if you are able to, take a picture of the mounts for the springs. The plastic triangle shaped piece that the spring slides through. This is mounted to the skid frame with a single bolt. Most of these I have encountered with any mileage on them at all are almost always bent because they use too small of a bolt. I have drilled out the skid frame and replaced them with a larger bolt to add strength to them. More importantly, check to make sure that yours are installed correctly. They should be installed so that the part that the spring slides in is ABOVE the mounting bolt. if it is below the mounting bolt, it will remove a great deal of the preload from the rear springs and also cause a very dangerous situation in which they could let loose and go right through your track (seen it happen before). If these have been replaced or altered in the past, either by yourself or the previous owner, it would not surprise me if they had been installed incorrectly. They are quite difficult to compress to get them above the mounting hole to put the bolt in them, but they go on relatively easy if you incorrectly mount them below the mounting hole.
 
#17 ·
That's quite a bit of sag, but it'll work. I think your problem still lies in the Kimpex torsion springs, the ones I bought for mine were junk brand new. I ended up going to a dealer and getting Doo springs and my problem was solved. The Kimpex shock isn't complete junk, but it will be in less than a 1000 miles and no way to rebuild it. Just my opinion mind you. :biggrin_old:
 
#18 ·
. Kimpex is crap? Never heard that befor.
really? im very surprised pretty much everything from kimpex is garbage .i think your problem is your front shock spring is no good i say this because few years ago my front shock mount broke and i thought i could drive the sled for a short ride with only the rear springs and the sled did exactly what your saying i only weight 150 and it would slam to the ground sitting on it now you being heavier plus the front spring is still doing something i think your front spring is no good. did you have to compress the spring it get the shockon/installed ? a good inch or two? when i did mine i had to use ratchet straps to compress it to get the shock in and the clip on
 
#19 ·
that cat in my sig pic has a sc-10 in it from my mxz and when two people sit on it it dont go down near as much as you say maybe 4 inches
 
#20 ·
So with some twiking this is what i have. I pull up on back end to 19 inches from floor to top of tunnel. Let go and it rest at 16 inches. Sit on it and it goes to 14 inches with some spring left. Does this sound right???
You need heavier torsion springs. They are rated for about a 200 lb rider from the factory. Your total sag should be about 2in just the sled, and about 3 to 4 in with the rider. Your current total is 5in, thus the need for heavier springs. The front shock spring does little for ride height, it is for adjusting ride firmness and ski pressure. I have the doo part numbers for the firmer springs if I get a chance tonight I will find them.

Sent from my ADR6425LVW using Tapatalk
 
#21 ·
I have used kimpex in many applications with out any problems in the past. Now im not jumping off cliffs or even catching much air. More hill climing than anything else.But i do belive in you get what you pay for.
With eight sleds i do try and watch the bottom line. If you find the part number for the heavier springs. I thing im going to need it. Thanks.
I have made a tool that colapses the spring so changing shocks is not a problem. Started with a wine bottle corker. I also removed the skid. Just makes it much easier.
Thanks for the replies.
 
#24 ·
Those part numbers are for the sc 10 3. Don't worry as the torsion springs are the same for the 1, 2, and 3 sc 10 suspensions. I believe they are rated for a 265lb rider on the firmest setting. BRP also has a set of springs that are heavier than these (300lb i believe), but i do not have that part #.
 
#25 ·
I measured up a 97 mxz with a sc-10 and got 24 1/2 c to c.
I measured a 96 mxzx and got 24 1/4 c to c.
Mine was at 24 5/8 c to c.
So I had nothing to loose. Got the drill out and drilled new holes on both sides. C to c now 24 3/8 approx. Bolted skid back In. And had to set springs on second settings to get it to give some. Is there some differences between sc-10 skids???
Nothing binding that I can tell. Weight transfer is great. Still have bigger springs on order.
 
#26 ·
The front shock spring does little for ride height, it is for adjusting ride firmness and ski pressure.

Sent from my ADR6425LVW using Tapatalk
take your front spring off and sit on the sled and than tell me it does little for ride height. lol when i took mine off the sled would bottom out with me sitting on it not moving and i weight 145 so its not like it was over loaded . it does do more than you think .my buddy who weights 380lbs can sit on my mxz and it dont squat as bad as the OP is saying. i also put HD spring on his 96 mxz and it still slammed to the ground changed front coil spring and it was fixed .

so to the OP if you change your rear springs and it still sags change your front coil spring and it should be good

96 and 97 mxz's have the suspension mounted in there a touch different. i dont know why they just do that just one of the many differences from 96 to 97 my 97 rear hole was about 3/4" lower to the ground vs my buddys 96
 
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