Blowing up Chaincase twice

[‘17Rtx]

I have a 2017 RTX SE. Was riding in Ontario when I felt a thud and noticed my sight glass had fallen into my case. Safe to say that ride was over, spilling chain oil all over the trail. Took the case apart and noticed the idler bolts were sitting in the bottom of the case as they had come loose and likely caused my chain to hit my glass and cause this mess.
No big deal, took it to a mechanic who tack welded the bolts, new case cover assembly with no other damage other than a replaced chain link. Im in Quebec the following weekend and about 20km into my 800 km trip and boom, felt like the exact same thing had happened. Took the case apart and the bolts are still tack welded securely in there, sight glass is once again sitting on the bottom of the case when I took it apart.
I assume this is a fried bearing somewhere, or a warped drive or jack shaft. Anyone else have this issue?

 

[Turboflash]

I have a 2017 RTX SE. Was riding in Ontario when I felt a thud and noticed my sight glass had fallen into my case. Safe to say that ride was over, spilling chain oil all over the trail. Took the case apart and noticed the idler bolts were sitting in the bottom of the case as they had come loose and likely caused my chain to hit my glass and cause this mess.
No big deal, took it to a mechanic who tack welded the bolts, new case cover assembly with no other damage other than a replaced chain link. Im in Quebec the following weekend and about 20km into my 800 km trip and boom, felt like the exact same thing had happened. Took the case apart and the bolts are still tack welded securely in there, sight glass is once again sitting on the bottom of the case when I took it apart.
I assume this is a fried bearing somewhere, or a warped drive or jack shaft. Anyone else have this issue?

What was "boom" you describe? Sight glass falling in by itself shouldn't cause a "boom" unless it got between chain and gear.
How loose was chain? Was it so loose it was hitting center post?
Is rest of case parts assembled correctly? Is tensioner spring installed correctly?
Are shift fork pads ok?
How much oil was in it?

 

[‘17Rtx]

I may have exaggerated. Was a clunk, not a boom.
Chain tensioner was good
Oil was just changed and put to 3/4 of glass
Shift fork pads I don’t know about
I did over heat the sled the night before and this happened in the am of the following day (the first time). But the two previous days I put on 800 clicks and all was well.
Perhaps the mechanic isn’t as knowledgeable as everyone claimed and put it back wrong

 

[Turboflash]

I may have exaggerated. Was a clunk, not a boom.
Chain tensioner was good
Oil was just changed and put to 3/4 of glass
Shift fork pads I don’t know about
I did over heat the sled the night before and this happened in the am of the following day (the first time). But the two previous days I put on 800 clicks and all was well.
Perhaps the mechanic isn’t as knowledgeable as everyone claimed and put it back wrong

Well, just because the chain tensioner was "good" doesn't answer the question. Was the chain tension adjusted correctly?
Meaning turn adjuster bolt all the way in (by hand as tight as you can) then backing it out 1-1/4 to 1-1/2 turn?
With new sleds, the chain stretches fast and needs to adjusted the first few rides for sure. Need to keep and eye on them often.
Back to question about whether or not the rest of the case was assembled correctly? Many many 998 sleds out there have ridden countless miles on big HP and never had an issue.

 

[‘17Rtx]

Well, just because the chain tensioner was "good" doesn't answer the question. Was the chain tension adjusted correctly?
Meaning turn adjuster bolt all the way in (by hand as tight as you can) then backing it out 1-1/4 to 1-1/2 turn?
With new sleds, the chain stretches fast and needs to adjusted the first few rides for sure. Need to keep and eye on them often.
Back to question about whether or not the rest of the case was assembled correctly? Many many 998 sleds out there have ridden countless miles on big HP and never had an issue.

Chain tensioner was done exactly how you said it, to 1 and 1/2 turns. Mechanic is taking it back in on August and vows to make it correct as it was likely his mistake. I suspect a bad bearing on the clutch side making it whip around.

 

[InRBigness]

great that he is going to make it right. Once you are into the chain case I always replace all the bearings. Just cheap insurance and way less than replacing the case parts.

 

[Sevey]

The bearings on these sleds - both clutch side and chaincase side - seem to hold up incredibly well. I cant believe it was a bearing failure.

Regardless - the whole case needs to come apart and each part inspected. Only then can you look at the bearings and look for a cracked ball or broken cage.

Keep an eye on the upper sprocket for excessive slop, check the pads on the shifter fork, look to make sure the snap rings havent broken or snapped off.

Good luck
MS

 

[‘17Rtx]

Thanks

 

[NYTurbo]

Where abouts are u located ?

 

[‘17Rtx]

Toronto Area, Ontario

 

[earthling]

Arts Sled Shop, just north of you is the place to go. They bleed blue and know what they are doing.

 

[‘17Rtx]

Yep Blair was the one who originally dealt with it. Won’t get it in till august but I trust he knows what to do

 

[Stubbs]

If Blair had his hands on it the first time I find it very hard to believe it was reassembled incorrectly. Smart money is on another component failing, which is really shitty luck for you. Sorry to hear your trip was ruined by a bullshit design.

 

[‘17Rtx]

I’ve only ever heard good things about him, definitely not knockin his expertise. Once I get it fixed I’ll see what he says is the issue.

 

[earthling]

You are in good hands. Blair will get it sorted out.