Chain case, what are the real issues and challenges or relatively trouble-free?

[Conedodger]

I've read a few threads but trying to zero in on what's normal vs the few odd failures. Yes you won't catch the odd failures if you don't look.

book says inititial tension, 300 miles, every 500 after. Change oil every season. Which of course will happen/should happen if tension is checked every 500m.


I've confirmed some dealers just use suction guns, so that's subject to interpretation.

My first 3 day wknd was 471 miles so I already missed the 300 mile check tension recommendation

If I check tension every 500 miles, that's EVERY trip and seems excessive.

I live 1400-1800 miles from my sled so that complicates things.

You can give up to 4 answers.

 

[WinterWolf]

Hey Ken,

When I go back up in February, gonna have Garys do the 500 mile service. I’m gonna have him check it all over obviously...change fluid tighten the chain as well. I noticed mine would “clunk” sometimes when coming to a rolling stop, and then getting back on the throttle, at the end of my trip. So I’m thinking the chain has stretched since it’s brand new...and that’s what is causing the clunking from time to time..had that on previous sleds.

 

[Conedodger]

Hey Ken,

When I go back up in February, gonna have Garys do the 500 mile service. I’m gonna have him check it all over obviously...change fluid tighten the chain as well. I noticed mine would “clunk” sometimes when coming to a rolling stop, and then getting back on the throttle, at the end of my trip. So I’m thinking the chain has stretched since it’s brand new...and that’s what is causing the clunking from time to time..had that on previous sleds.

Mine won't see Caribou til about a yr from now. But I have a great friend in CT I used to race with in the 80's (mud drag cars) who was a doo and cat dealer for many years. He's super anal, live's 20 minutes from dad and does a little sled work on the side for his circle of friends. So I'm in good hands.... but the thought of opening the chain case every 500m seems a little crazy. I wonder if it can be borascoped?

 

[Motorhead]

It should be opened each year for inspection and oil changeout.
Ay every 500 mile interval ( chain tension adjustment). If adjustment bolt has way more free play then how you left it 500 miles previously, you better do an internal inspection and cleaning. Mine stretched a whole turn and allowed the chain to wear down that nub in inner chaincase, much like shown on a previous Viper post!

Hoping the chain will not stretch anymore after 1400 miles. Yes intervals and break in by the book.

I will say that if you baby it first 500 miles like the book wants, the chain will not stretch much. But when you start riding it like it was meant for, that chain will stretch a lot. So that is the time to keep it in check!

This ain’t no Yamaha of past chaincase!!!

 

[Conedodger]

Confession.... I turn wrenches all the time, but rusty on turning wrenches on the sleds.... I was thinking you had to open the case to set tension, which of course is not the case. I've seen the worn nub thread. And no, it's not babied. Mind you it wasn't pinned for long duration but it's been run.... I'm of that school, just vary it a lot. That said, what a shitty design to remove so much stuff just to set tension. at least it will serve to keep fresh antiseize on the bolts.

 

[Fleecer]

While riding last week my sled came out of forward and I heard a grinding noise. Had reverse, but no forward. Cycled it a few times forward to reverse, shut sled off couple time to reset servo with no luck. Rode it back in reverse as long as I could, but buried it trying to get through a drift....had to walk home about 3/4 mile at -15F. Could have been worse, but wasn't happy. Two top gears were stripped. Sled had 1900 miles with a tune! At 500 miles changed upper gear/oil and everything looked good.

Dealer warrantied 2 top gears and a new servo motor. Not sure what caused it...perhaps belt tension too tight and didn't go into forward fully from reverse last time shifted or perhaps servo motor wigged out and pulled it out of forward on it's own?? Hope that never happens again. While disassembled, noticed one of the bolts that secures the chain tensioner wheel was loose. There are two bolts that hold this wheel, one on each side. Dealer Mechanic says he has seen these back out and start to chew the chain case. Something to look out for while you are in there.

Knowing what I know now, should this happen in the field again I would remove the servo and pull out the cylindrical shifter it is attached to. Then get a long screwdriver and pry the outside gear onto the inner gear while turning secondary to get them to mesh. This will at least engage forward. Put back together and don't plug servo....should get me home!!