Anybody know anything about Ski-doo alpines?

[kermit2]

We have a 1985 Ski-doo alpine at Challenge Mtn. that I have been working on since last March. I had to rebuild the transmission. When I got to the part about adjusting the chain, I don't know what to do,and after some trial and error, seemed to have it right. When I finally got the chance to use it in the snow it worked fine on the flatlands. Then last night I was messing around and I took it up the hill. It started to spin the tracks towards the top and I didn't even think about which gear I was in so when I got up to the top I switched gears, (I still didn't know if I was in 1st or 2nd). I went around to take a flatter run down and halfway between the two the tranny locked up again. I wasn't going fast, but it stopped, like right now. I had no tools, and I was the last one there, so I had to walk(slide) down.I got back up there today after we were done and messed with the adjuster and it moved. I buttoned it up, took off and it started to make a noise like the chain was loose, I slowed down, and buried it. Shifted into reverse and it walked right out. When I turned around and put it back into forward it make the noise again.... I drove it down in reverse,didn't want to tow it. WOW what a rush going backwards, down a ski hill, on a one ski, two track 600 lb piece of Canadian art!
Can anyone tell me the proper way to adjust the chain on this prehistoric beast? After the ride of my life I want to make sure this SOB finishes its life being useful not beautiful.
I have the 1985 skidoo shop manual with a complete breakdown of all their sleds on my computer, but they have no mention on how to adjust the chain. As I recall the tracks were elevated when I did it. Someone told me that was wrong. I can't see how , but what do I know? I sure the hell aint no snowmobile mechanic.
Anyone ever work on one of these beasts?

 

[alaska120]

Hey Kermit. I've had a couple and I'm sure there are others out there as well. Most of mine were single speed. 399 cc twins. One was a 640cc twin with high/low/rev.
If I recall, there is a rubber plug about 4 inches in diameter on the side of the case that can be removed to look at the chain.
Things to look for...
Are the teeth all ok on both gears?
Are the bearings on the shafts in good shape?
The adjuster should not be turned too tightly. I usually set them up so the chain is just barely snug and lock it down.
The only time I had trouble was with a really high mileage machine - like 60,000 miles - where the chain had stretched out and the teeth were worn. Sometimes the chain would 'ride up' on the gears and get pinched between the gear and the case.

 

[Snowtrac Nome]

we had them in the national guard for lots of years you ratate the jack shaft till the chain is loose on the adjuster side and tight on the oppisits side turn the adjuster with your fingers till it's snug and lock the set nut if you lost adjustment that fast i'm thinking something went wromg look closely at your driver bearings and jack shaf bearings best case you just need a new chain