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Rolling a chaincase on a 91 sks

M
Ok I got the rear skid all fixed now I ended up moving the front back a total of 4 1/2 inces (the extra 1 1/2 was becase aparently I have a 133 skid and not a 136) and had to move the rear back a total of 6 inces. Does this sound wierd to anyone?
 
V

volcano buster

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Nov 26, 2007
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Stayton Oregon
I hope it works, but I question the 6" set back. The tunnel mounts should not be different from a 121, 133 or 136 (unless you are swapping out a different suspension type or model), so that set back should be standard. Now that you point out the modified rear scissor, that part would make me nervous. I had a similar issue with my XLT that I put an Xtra-10 rear skid in. I moved the rear mount back forth a bit and finally quit. I never did get it quite right but it ran fine.
 
M
Well took it out for a spin sunday and everything seems to work great. It doesnt seem to have the top end power it used to probably cause of the longer track but was thinking do I need to re do my clutching now? I think maybe I moved the rear suspension bracket back to far and that my travel issue I was having was because I had it dropped down to low? wouldnt that make all the weight transfer to the back and compress everything? was maybe thinking about doind a x10 swap but dont know much about it what is different about it?
 
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X2Freeride

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Jan 25, 2009
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I hope it works, but I question the 6" set back. The tunnel mounts should not be different from a 121, 133 or 136 (unless you are swapping out a different suspension type or model), so that set back should be standard. Now that you point out the modified rear scissor, that part would make me nervous. I had a similar issue with my XLT that I put an Xtra-10 rear skid in. I moved the rear mount back forth a bit and finally quit. I never did get it quite right but it ran fine.


It would depend on if your talking a coupled skid or a non coupled skid as well. Plus his chain case has a drop and roll moving it back. Stock mounting HAS to change in that case because the rail tips are closer now to the drive shaft making the mounting wrong. I know 100 percent for sure that the 121 skid has a much narrower center to center than ANY 136 of that vintage even the coupled 136 on newer sleds still doesnt mount the same as a 121 does. The 133.5 is even different than the 136. Where the skid mounts in the tunnel (IF ALL THE CRUCIAL MEASUREMENTS ARE CORRECT) has nothing to do with how it performs other than increasing steering pressure as the skid is set back. The distance from the center of the drive shaft to the front mounting points, The center to center, and the skid height in the tunnel both front and rear matter a lot more then where the skid is in the tunnel.

See my posts below with the measurements.
 
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X

X2Freeride

Well-known member
Jan 25, 2009
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Ok I got the rear skid all fixed now I ended up moving the front back a total of 4 1/2 inces (the extra 1 1/2 was becase aparently I have a 133 skid and not a 136) and had to move the rear back a total of 6 inces. Does this sound wierd to anyone?



You moved your case back which moved your drive shaft back so naturally your skid would need to go back too. This is what I was trying to see by the pictures. I hadnt been on since to see what you posted.

What you should have done is measure front the center of the drive shaft to front mounting hole 1. When you were stock. Then the center to center of the mounting points in the skid when stock. Then the height of the skid mounted in the tunnel both front and rear stock.

Then after completing your drop and roll take your measurements and apply them to the new drive shaft location. Drill new holes and mount the skid in the new location. With your drop and roll your going to have to move the mounting points of the skid back farther to compensate for your new drive shaft location. they you would be keeping the the same stock mounting specs for the skid while taking into consideration your new drive shaft location.

Make sense?
 
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X

X2Freeride

Well-known member
Jan 25, 2009
1,546
582
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Well took it out for a spin sunday and everything seems to work great. It doesnt seem to have the top end power it used to probably cause of the longer track but was thinking do I need to re do my clutching now? I think maybe I moved the rear suspension bracket back to far and that my travel issue I was having was because I had it dropped down to low? wouldnt that make all the weight transfer to the back and compress everything? was maybe thinking about doind a x10 swap but dont know much about it what is different about it?

your primary spring and weights should stay the same but you need to update your helix and gear down to compensate for the longer track. that will bring some of your speed back. But your never going to be super fast with that long of a track.

Here are two pictures of the X10 mountings. One is for a 136 and longer skid the other is for the 121 skid.
 

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