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Discussion Starter · #1 ·
New to the forum here so, greetings.
Last winter my dad broke the chain on his 1990 Mx, and when towing it back the chain must have bunched up at the bottom of the case and it busted a hole through the bottom of the casting. He decided he would opt for the reversing chain case instead, so I installed that for him Along with the sc3 long track conversion and tunnel extension. when I finally started it up and drove it out the shop, I went to try the reverse and it only went an inch backwards before locking up. Shifting back into forwards, it unbound and drove fine. Upon further investigation, I’ve found that if you spin the secondary clutch backwards while the sled is in reverse, it will go forwards all day long, but as soon as you turn it in the normal direction, it will go backwards about an inch and lock up again.
Hopefully all what I said makes sense, and any help I’d much appreciate
 

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I know the reversing secondary on the Polaris models takes a different helix than the forward only ones. There has to be a ramp in both directions for the clutch to work in reverse. You will need to get a reverse capable helix or a secondary off a Skidoo that has RER.

Don't listen to me, I have no idea what I'm talking about ;) I was thinking RER all the way. Sorry about that!

Welcome to the forum!
 

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The secondary will still move in the forward direction no mater if the chain case is in forward or reverse. The reverse takes place in the chain case. With newer sleds, the motor runs backwards allowing the sled to back up. Your year Skidoo does not have RER like Dan is talking about. This is where the motor runs backwards.

It sounds like something is not where it should be in the chain case and is causing it to bind up.
 

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I agree with Snowmoer. I think I'd take the chain case cover off and just watch it. Won't hurt it to run without fluid for a few minutes while you test it. Chain tension is important.
Older mechanical reverses ran the clutches in the same direction. The reverse was done in the chain case.

Also, check the drive axel and make sure the bearing is not shot on the clutch side of the driveshaft.
 

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Discussion Starter · #5 ·
Thanks for the replies,
Now I did replace both bearings on the drive axle when I changed the track so I don’t think they are the cause of the issue. I think something is definitely binding up inside the chain case but I don’t know what it could possibly be.
I’ll split the case tomorrow and take a look, but Im pretty sure the fork to engage the reverse was on the cover side of the chain case, so if it doesn’t have the cover, I don’t know how I could make it stay in reverse to see how it locks up. Any suggestions on how to go about this? Would removing the spring work?
 

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is it too long of a chain , i could see it bunching up in the case causing it to lock up, or wrong pitch,,,,, drive load revs when in revs, ie load goes against the tensioner
 

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Discussion Starter · #7 ·
A couple days ago, I finally figured out the issue with this chain case. I didn’t have much luck testing it with the cover off, but when I had the case all apart, I noticed how on the plate that holds the chain against the reverse gear, the bolts they used were a bit too long and they sat proud of the flattened surface on this plate. So I guess what happened was that as soon as there was load on the reversing gear, the chain had the tendency to push against that plate, and due to the way the links on this chain were grouped, there was a big enough gap for the ends of these bolts to fit into causing the jamming problem. I Shortened these bolts a bit on the belt sander, got it all back together, and now after all that, I finally have it working.
 

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New to the forum here so, greetings.
Last winter my dad broke the chain on his 1990 Mx, and when towing it back the chain must have bunched up at the bottom of the case and it busted a hole through the bottom of the casting. He decided he would opt for the reversing chain case instead, so I installed that for him Along with the sc3 long track conversion and tunnel extension. when I finally started it up and drove it out the shop, I went to try the reverse and it only went an inch backwards before locking up. Shifting back into forwards, it unbound and drove fine. Upon further investigation, I’ve found that if you spin the secondary clutch backwards while the sled is in reverse, it will go forwards all day long, but as soon as you turn it in the normal direction, it will go backwards about an inch and lock up again.
Hopefully all what I said makes sense, and any help I’d much appreciate
Did you adjust the chain there's a bolt on top you can adjust wit fingers
 
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