I finally got my 1997 Storm dialed in just the way I wanted it. Clutching, 1.25" Predator track, suspension - everything was right.

Tonight, after 1500 miles since installing the track, I was out with a few buddies and out in front. We came to an long open field and I cracked it wide open and started to rocket across the field. All of a sudden at about 75 mph "BANG" - no more acceleration. I hit the brakes and nothing happened. I shut the motor off (still going about 40 mph) and could hear grinding noises - I guessed the chain had let go.

Eventually we got the machine back home and pulled it apart. Sure enough the chain had broken. What was worse was the chain tensioner was also shattered at the pivot and even worse the cast in pivot post for the tensioner had snapped off the chaincase, leaving a hole in the backside of it.

This is the first time in 25 years of sledding I've had a chain go. What typically goes? Does the chain simply fatigue and eventually break or did something happen to the tensioner first? What confuses me is 3 weeks ago (admittedly 1500 miles ago) I very carefully checked the chain under a bright light. It looked perfect and I spent at least 15 minutes looking at every link. It also didn't seem too sloppy, nor pull away from the gears too much.

I'm afraid this is going to be a big $$$ repair. I figure a used chaincase, new chain, gears (it has reverse, so the "non standard" lower gear has a bearing too), seals, cover seal (got shredded), tensioner assembly, etc.

Any suggestions? Recommended places to find the parts? How often do you guys replace your chains on high performance machines?

One thing that scares the heck out of me is about 10 minutes earlier we were running down a very twisty trail through a forest. Every straight away was close to WOT with threshold braking before each turn. If the chain had let go there I might not be writing this now...

Spoiled sports Bomanville ont.two years ago used chain case was 90 dollars. chain not sure maybe 80. (95 storm)

spoiled sports definately just email them and ask, there is also Dillabough sales and service which may be a little closer to u in Merrickville (1-613-269-4726) and if that dont pan out you could try cycle salvage in oshawa, hope you can find it

Are there any advantages switching to a Hyvo chain and sprocket set?

Steve800,

First let me say sorry to heare about the sled.

It sounds like you were on top of checking things.

When I put a new track on the Ultra, I found a bad link in my chain, a link was half off, slipped off the pin,Where it was peened over.
It was bad new's just waiting to happen.

I got my chain at,Northern wholesale supply,In Mn,
1-800-333-7777or 1-800-666-1111
www.northernwholesale.com

If you need help getting in there let me know,(you may need an acount#)
JohnK

I had a good look at the broken chain. None of the links are off the pins. The chain snapped clean through a set of links halfway between the pins. There are a few other places where a few of the links have broken too (near the center of the chain - the edges links are fine).

Supposedly the hyvo chains are stronger (according to a couple of Polaris dealers I called for parts) so I'm leaning towards changing to them.

Anyone reading this have any experience with them?

IMO the extra tension that the new track put on the stock chain was to much. In the future it would be a good idea to run the largest chain the the case will hold and good syn. oil. While you are at it check the bearings on both side and maybe even upgrade them as well. SWRules

If you can just promise anyone with any sled they wont ever have any problems you should get into the insurance business!

Go out, do yourself a favor, and buy a ski-doo mxz rev. Trust me, you will never have any problems.*

I think I would rather have that problem with the chain breaking on that Storm, rather than having the problem you would have staying out in front with him. Then going back to the bar and having all your friends give you crap about it. :D

Not all of us have the money to spend on a new sled, so we deal with what we have. And FYI, I'm pretty sure all the guys in THIS part of the forum would rather buy a 04 Pro-X.

I'm not saying that the Revs, or as I call them "The sled that the CHEAP, I CUT OFF EVERYBODY racer Blair Morgan rides" are bad sleds. I dont mind them.

Steve800 - My buddy has the same sled, but with a 1in camo and 1.25 woodys and hasnt had a problem with the chain. I believe he runs amsoil in the chaincase. That thing really rips! It makes my 98 XC 600 look pretty stupid sometimes. :angry: I would try what BGTRK19472 - Use the biggest chain possible and update your bearings. This should solve the problem. Good luck with it and let us know how it works out!

SWRules

MXZrider7c - No hard feelings. :thumbsup:

First off since running 600-700 miles with Amsoil I had 4 times the metal shavings as I did with Polairs chain case oil. I put regular auto tranny fluid in this time when i pulled the chain case off. Seems alot of guys like the Polaris chain case oil. Go on Ebay and you'll find all the parts you need dirt cheap. I've seen new Hyvo gears sell for a buck a piece. And there are tons of Polaris gears and chains on there. And a new Polaris chain case is only likle 100 bucks give or take a bit I believe. I know a guy with a complete set of gears, and extra gears along with the complete chain case out of a 97 Ultra SPX he parted out instead of selling. I bought a bunch of parts off him for my Ultra SPX. And your sled is an aggressive chassis so they fit. Let me know via email at clamley@yahoo.com .

I could be interested in the chaincase depending on where you're located. I'll send you an e-mail. As you say though a new one isn't much. Unfortunately the gears won't work as the Ultra came with 21/35/64 (top/bottom/chain). I'm currently running 23/37/66 and I'd like to go with a 25/40/70 (which isn't recommended with the silent chain - have to go hyvo).

I wouldn't recommend running straight auto tranny fluid in the chaincase though. It really doesn't provide much wear protection. The highest level of protection for gears and chains is GL-5. I'm pretty sure auto tranny fluid doesn't even meet GL-4 specifications (except for some of the specialty synthetic fluids like Redline ATF). Personally, in the past, I've always run a low viscosity gear oil that meets GL-5 (except last time). I normally run a 75w90 fully synthetic gear oil (GL-5). I'm not sure what the offical chaincase oil is, but I put money on it being a slightly lower viscosity gear oil, possibly with moly or graphite added.

After installing the new track I decided to switch to Polaris premium chaincase oil. The chain only lasted 1000-1500 miles with it, but I doubt it was the fault of the lube (the failure looks like a sudden stress fracture).

I could be wrong about running ATF in the chaincase. I believe this specifically applies to Hy-Vo chain systems, not standard silent chains. Here is a portion of a post that I found on the web:

From: bearbvd@xxx.net (Greg Hermann)
Date: Sun, 15 Nov 1998 20:23:37 -0700
Subject: Re: trac. contr.

>On Sun, 15 Nov 1998, Greg Hermann wrote:
>
>> Once was in charge of a bunch of wear testing on that type of Chain
>> (Hy-Vo). The test machine was set up to run Toro/Eldo chains, but no big
>> deal. FWIW, ATF gave 100% better chain wear than any type of conventional
>> gear oil. Synthetic gear oils (then pretty new stuff) did even worse. Note
>> that the Torp/Eldo used a 3/8" pitch chain, 2" wide between the converter
>> and tranny--an excellent application, which rarely wore out. Transfer cases
>> apply the chain between the tranny and the axle, also after the low range
>> gear, still use 3/8" pitch, sometimes 1/2" pitch chain, varying (I think)
>> from 1-1/2" to 2-1/2" wide, depending on application, and about the same
>> size sprockets. It does not take a rocket scientist to figure out that
>> these chains are loaded a lot more heavily, and do wear out, pretty
>> regularly.
>> >
>> >You're right about it being sensitive to the oil.
>>
>Hy-Vo chain was/is used for lotsa industrial apps too and in their catalog
>they have [or had...] a chart showing acceptable power loading for various
>pitches\widths depending on viscosity and type of lubrication system. Use
>gear 90 and the rating tanks. Pressure lube with 10-30 or ATF and the
>rating goes up, way up.
>
>The old NP 203 used to eat chains with gear 90. Never a problem with
>reccomended oils [ignoring the idiot factor here]

All true--I knew, liked, and took some courses from, later worked with, the
guy who had his name on the Hy-Vo chain patent--Prof. J. O. Jeffrey,
P.E.--better known to his students as "Jominy Joe". Quite a character.

What goes on inside the chain is that the EP additives in the hypoid type
oils eat up the surface of the chain pins chemically where they roll
against each other, because of the high contact pressure. The beauty of
this chain design is that there is no rubbing contact (under load) either
inside the chain or where the chain meshes the sprockets. Meshing of chain
and sprocket is exactly like a straight rack and a gear -rolling tooth
contact only, but then the chain folds around the sprocket, and there is NO
rise and fall of the chain onto the sprocket with each tooth, like what
happens with a roller chain or a silent chain. That is what makes the "High
Velocity" possible--no chain to sprocket tooth impact. Also why the
Toro/Eldo app was a LOT better and more durable than the NP203 app--ran the
chain faster, with less chain tension load--took better advantage of its
capabilities.

I examined the chain even more closely and noticed that the damaged links (where the chain didn't snap) were all damaged where they touch the reverse pickup gear (the chain rides along the gear - don't know the official name for it). Looking at the gear it makes sense that the chain would be highly stressed here because the gear is too narrow for the chain. Polaris seems to use a common reverse kit for basically all of these sleds and the gear is sized for a narrower chain. Running the 15 wide chain puts a lot of stress on the links near the center of the chain.

I'm hoping that there is a Hy-Vo reverse pickup gear available properly sized for the 3/4" chain. Running the 25/40 gears (larger than current 23/37) should also reduce the force on the reverse pickup gear (both because there is less tension on the chain and because the chain will naturally ride closer to the edge of the chaincase).

I have a 96 storm that this happened to a few years ago. It's kind of a spare sled now. Didn't damage the case though. I ended up having to replace the chain and gears. I used an erlandson chain. They claim to be stronger. I also had to replace the reverse gears. While I was in there I replaced the case bearings, why not? The case had a lot of little bits of steel in it. I decided that it was from the reverse grinding on engagement at times. I just change the oil in the chaincase more often than before. I also pull the stick as often as I think of it and wipe the bits off the magnet. Dip it a few times and rewipe. So far so good. Incedentally, I use only polaris synthetic oil.

:D