HELP: 2nd blown chaincase

[stevewithOCD]

Just blew my chaincase for 2nd time in 2000 miles. First let me fill you in. I'm stevewithOCD because i've been absolutely addicted to snowmobiling for 35 years since my first sled at 5 years old. I've been reading Totally Yamaha for almost 2 years & this problem has forced me to sign up because i don't think the dealers are going to fix it correctly. I own a '06 Apex ER. At 300 miles i had it serviced & next ride BOOM! I had it repaired under warrenty & was told it was the tension pulley. Now it's blown again & sounds like same thing. I haven't taken it apart yet until i find out about warrenty issues. I ride with other Apex's & no probs so maybe mine is a lemon. For the record i'm very mechanically skilled & have ripped apart, re-assembled & blown up & re-repaired just about everything on snow. Not bragging, just stating. PLEASE HELP! Any experience with this will help...

 

[ReX]

Do a search on this forum for chaincase oil leaks.

The 06 and 07 Apex's had a weakness where the chaincase cover gasket works its way into the chaincase. The harder you ride and the more heat cycles the chaincase goes through, the more likely it will leak.

When it goes, all of the oil leaks out quickly and if you don't notice almost right away (if you're riding hard) they fail.

On the other hand, as long as oil stays in the chaincase, these are very durable chaincases - much more durable that your typical Cat, Polaris, and Skidoo.

What you need is the updated 2007 chaincase cover or if you want the coolest running chaincase you can bolt on a 2005 RX-1 ER chaincase assembly (using the innards from the 2006 Apex). The 05 was made out of aluminum which conducts a lot better and the magnesium used in the 06 and up chaincase. Other than the material and the improved gasket geometry on the 05, the 05 vs 06/07 are identical. The updated 07 chaincase cover also has very good geometry for the gasket and doesn't leak.

 

[stevewithOCD]

Thank you ReX! Although oil was full to the "reverse" mark even after problem, i will definately update when i do repairs. 2 different kinds of oils were used & tension was set to manual specs. Even with an oil problem; why would tensioner fail? When i take it apart i'll have more info to report on...

 

[ReX]

Thank you ReX! Although oil was full to the "reverse" mark even after problem, i will definately update when i do repairs. 2 different kinds of oils were used & tension was set to manual specs. Even with an oil problem; why would tensioner fail? When i take it apart i'll have more info to report on...

I don't know. The guys I ride with and myself have put over 50,000 km on these sleds and the tensioners have never failed, even on the sleds with chaincase oil leaks.

The only thing I've heard of is they apparently can fail if the chaincase oil isn't changed enough. We change ours every 3000 km, along with the engine oil. We usually run generic Quaker State synthetic 75w90 gear oil (or whatever synthetic 75w90 is available at the time).

How many miles are on your sled?

 

[HIGHLAND_GT]

I think that the oil level has to be above the reverse mark and that the amount of oil is 250 ml in the case. If the level is lower, the chaincase will heat up and there is not enough oil to remove the heat, causing the seal, gaskets, and bearing parts to fail.

Do a search and you will find that in 2006, they had some failures due to low oil level in the chaincase.

 

[Snoopy]

Have you checked if axles have been bent?
If it´s just bent a little, maybe it could cause
that kind of fault to the tension pulley after some time.?

Sorry if my english isn´t correct, but hopefully you understand me anyway.

// Snoopy from Scandinavia

 

[barto]

I lost my chaincase last year when the tapered retainer came loose on the jackshaft. This is the collar that holds the jackshaft in the bearing behind the secondary. When this loosened, the shaft started to wobble in the chaincase, trashing the bearing, gears, etc.

 

[ReX]

I think that the oil level has to be above the reverse mark and that the amount of oil is 250 ml in the case. If the level is lower, the chaincase will heat up and there is not enough oil to remove the heat, causing the seal, gaskets, and bearing parts to fail.

Do a search and you will find that in 2006, they had some failures due to low oil level in the chaincase.

We've run ours both above and at the full REV line and never had issues (except for the leaky covers). I'm confident filling it to the full mark for reverse sleds on a sled with reverse will not cause a failure.

 

[stevewithOCD]

OK, i took apart chaincase. Tension pulley mounting stem broke off case. There was still oil in it even though alot came out hole where stem was. There was fresh oil [ 400 miles ] both times. First time was Yamalube & second time was synthetic. I do not believe this was an oil issue. I'm going to check gears for true & square. I'm also going to call shop & get details of what was done first time. I's possible there was a simple problem the first time that didn't get repaired correctly. If i don't find a definitve answer i'm not sure i can trust this sled anymore! It's ruined 2 trips! ANY input, info or opinions would be HUGE!

 

[AttakDog]

Never heard of this casting breaking off. Even if the chain was tightened with a wrench I'm not sure it could happen. Must be getting some kind of side load or severe mis-alignment.

 

[stinx]

I had the chaincase cover on my 06 Attak updated to the 07 cover last season. After a Highspeed run in quebec I could smell what I thought was oil, I stopped and checked and had no oil in my chaincase. WE filled it with injector oil and a rode it easy the rest of the day. I have had no issues since the addition of the 07 cover/gasket My sled curretly has 3800 miles on it

 

[stevewithOCD]

Thanx guys. I plan on changing every single part in there & upgrading to newer parts. I'll run best oil i can buy, but confidence is shot until "why" is answered. Still looking into first repair. Will know more when i have time next week...