[Zpider]

How can i check the chain tension on my EXT 580 with reverse? Is there any way to do it without removing the case lid?

The sled jumped out of gear when running on the lake here, felt like the chain smacked right off and the engine rewed out, but when slowing down it suddenly engaged again, and since then it has not happen again. I heard that this could be due to a loose chain. Any other ideas on the cause for it jumping out of gear?

 

[tcat446]

I would pull the chain case off and take a look. Never know what you may find. May be an adjustment or some new parts. Better pull it apart! Does that have the auto adjust or just a bolt with a nut? Can you post some pics of the opened up case?

 

[Zpider]

I hoped that it could be checked without pulling it apart

As far as i can see there are no external adjuster on the case, if so i guess that would be located on the right side seen from the ECU box, pointing forward on the sled, right?

 

[tcat446]

I'm not sure on that model to answer your question but I'm sure someone on here will know. I think it would be best to see if there was damage done inside so pull it apart. I know you don't want to but its not a bad job really. And it may cost more money not looking into it further. Drain the oil on the bottom underneath by the track. Pull the bolts and take it off. Really not a bad job.

 

[Godsmack]

If its jumping out of gear, you need to open it up and find out why. Its likely not just because the chain is loose...

 

[clintonior13]

it could be that your track ratched and needs to be tensioned. I'm +1 that you should check your chain case and inspect clean it out very likely milky oil in there if you haven't done it this year.

 

[Zpider]

I figured out that it jumps out of gear when running about 90 kmh. Under that its fine regardless of load.

Well, this is how the parts inside look.

Seems the pins on the secondary gear has gotten some beating:

And the holes also:

But this worries me the most, the back of the gear has rubbed against the bolts for the driveshaft bearing holder:

Also, the tensioner arm seems a bit bent, the roller is not in line with the chain. Can this be due to the chain smashing it when it jumps out of gear?

Any input on what to do next with it? The pins i guess can be changed, and the holes i can fix in my shop also, but what cases it to rub against the bolts like this?

 

[109jb]

... what cases it to rub against the bolts like this?

Is the spacer behind that gear missing?

 

[Zpider]

Yes, its there all right...

 

[109jb]

Is the lower bearing for the driveshaft on backward?

 

[Zpider]

From what i know this sled has never been taken apart before so hopefully its correct. I cant feel any play in the bearing so its seems ok, but i cant tell if its mounted correct.

 

[Zpider]

The thing is, ok, the pins and holes are a bit beaten, but enough to cause the gear to jump out?

The rubbing at the bolts could be that it doesn't connect fully though so that could be the reason i think...

 

[tcat446]

I would replace the beat up plate (#44) on the gear. With the washer (#5) behind the gear it shouldn't be touching the plate. See if someone has somehow replaced the bolts there with longer ones. If the pins are damaged replace them too. The pins (#45) look good but hard to tell it they are good all the way around each pin. You may need to adjust the gear through the linkage adjustments. (#52)
The adjustment tool pictured below can be made with a nut lock tighted to a bolt or a Popsicle stick with a line on it for that matter. The measurement is 1.750" and is accessible through the plug (#52). If its not engaging the holes in the gear all the way it will jump out. You will need to adjust the linkage to get it correct. Get your parts together and adjust and you should be good to go. Also check the condition of the chain guide (#22). sometimes they are missing, broken, wrong ones, or out of adjustment. They should almost be touching the chain. I think the measurement is like .010 or something like that.
As for the gear those are hard to come by and expensive so I'd run that one and see if you can get by with it.

 

[tcat446]

The thing is, ok, the pins and holes are a bit beaten, but enough to cause the gear to jump out?

Maybe. Especially if it is out of adjustment.

 

[Zpider]

The thing is, ok, the pins and holes are a bit beaten, but enough to cause the gear to jump out?

Maybe. Especially if it is out of adjustment.

The numbers you refer to, where can i find that illustration?

I do think you're right here about the adjustment, if the gear has been that close to the bolts i think there is to much space between pins and the hole. The bolts are the right size though, maybe one thread above the nuts only.

 

[tcat446]

I use this link for looking up parts but not to buy from. Your call.

Alpha Sports - Arctic Cat Snowmobile Catalog

 

[Zpider]

I just cant match the numbers for my sled on theese diagrams. Or are you looking at another model/year?

 

[tcat446]

Yes I was. Sorry about that was thinking of 6 things a one time. Here ya go.

 

[tcat446]

I will go back and edit post #13 for you.

 

[109jb]

The fact that the back of the bottom gear is hitting the bearing retainer bolts means something is wrong. Since you said that the spacer was there behind the gear, then it must be that the bearing is in backward. The bearing has a raised inner race on one side for the eccentric locking collar (not used). That raised inner race must be facing the right side of the sled or the gear will be positioned wrong.