1998 vmax xtc 700 with reverse,2nd broken chaincase!!??

J

jenfred10

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Hello , was wondering what would cause a bolt to break through the chain case??
When we bought the sled last year the there was a hole in the chain case where the bolt broke through,( the lower bolt that goes into the shaft ) we put a new outer case on and new bolt and my brother n law and husband used loctite.
Now all the sudden, 200 miles later the bolt broke through again???? Thanks in advance!! Jennifer
 
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did you clean the threads with brake clean, use red loctite, allow 24 hours for it to dry before adding oil and torque to the correct torque?
 
Just brainstorming here... Are the bearings associated with that shaft in A-OK shape? I'm picturing vibrations from a bad bearing, helping that bolt to vibrate loose. I'm just looking for an underlying problem.
 
01sxr700 said:
Does he have the shims in place? There should be 2 washer plates (Washer, Plate VX700XTCDB 90201-16245-00). 1 on either side of the gear set. item 26
http://www.yamahasportsplaza.com/oemparts/a/yam/5003bc78f8700212fc840092/track-drive-1
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I'm pretty sure they checked that after we bought it wondering the same thing. I asked my husband and he thinks so but will have to look again.
He is new to sleds, not riding ,but working on them. Our brother n law is good with them,but not sure on this one.
 
roudyroy1 said:
did you clean the threads with brake clean, use red loctite, allow 24 hours for it to dry before adding oil and torque to the correct torque?
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It was torqued, but with blue loctite and new bolt. Didn't use brake clean though. But he cleaned the threads with a thread chaser. Didn't put gear oil in it for a few days either.
 
shaggyzr2 said:
I've seen those bolts break from being over torqued.
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I know the other bolt wasn't broke,just backed out and put a big hole through the outer case .
Not sure on this one yet. As of now the head of the bolt is sticking through the outer case.
 
A couple of bucks said:
Just brainstorming here... Are the bearings associated with that shaft in A-OK shape? I'm picturing vibrations from a bad bearing, helping that bolt to vibrate loose. I'm just looking for an underlying problem.
Click to expand...

That's interesting that you ask that. I believe one is fairly new. The one on the chain case side maybe if I have the right? There hasn't been any weird noises,but he thought he started to feel some vibration here and there kind of like a belt starting to go bad. The belt looks like brand new,and only has 200 miles on it though.
He's really not sure if it was a vibration it was so minor.
 
Did you put the lock washer on the bolt? That right there could be your problem. Even if you let the loctite set up the oil could cut the loctite like it's never been put on.
 
Yeah, we don't believe there was a lock washer. We have the Yamaha service manual and just went by that.
Thats why we used blue loctite, that's what the book said to use.
 
When I had to pull my chain case apart last winter there is a lock washer on the bottom bolt, and it doesn't look like someone just got one at the hardware store it's the same color and finish as all Yamaha hardware.

A sealing washer? What for, there is nothing that the bottom gear bolt seals. It holds the extension shaft and spring cup onto the drive axle. If it's still 1998 spec then I would be almost certain that there was a update done to include a lock washer by the time my 02 came out. Either way, I would put a lol washer on it because the loctite is being dissolved by your oil.

Can we get pics of the busted case cover? To get the bolt that far out from the spring cup, to contact the case without the rest of the reverse parts falling off the shaft is amazing.
 
My mistake, after rereading the original post I realized which bolt. Was thinking of the small reverse idler gear bolt.
 
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01sxr700 said:
My mistake, after rereading the original post I realized which bolt. Was thinking of the small reverse idler gear bolt.
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That one does have the bonded washer. I still can't see how the bolt is working far enough out to push through the cover without the rest of the bottom drive parts falling off.
 
Backwoods M Max said:
When I had to pull my chain case apart last winter there is a lock washer on the bottom bolt, and it doesn't look like someone just got one at the hardware store it's the same color and finish as all Yamaha hardware.

A sealing washer? What for, there is nothing that the bottom gear bolt seals. It holds the extension shaft and spring cup onto the drive axle. If it's still 1998 spec then I would be almost certain that there was a update done to include a lock washer by the time my 02 came out. Either way, I would put a lol washer on it because the loctite is being dissolved by your oil.

Can we get pics of the busted case cover? To get the bolt that far out from the spring cup, to contact the case without the rest of the reverse parts falling off the shaft is amazing.
Click to expand...

Thanks for the link! We know which lock washer you mean now. Yes, that one got put on during reassembly. I will try to get pictures within the next couple days. I don't think I will have time tomorrow.

We wouldn't have even known it was broke if my husband didn't see gear oil on the trailer after a ride,but as of now its just the bolt head sticking out of the case( the whole bolt head)

When we bought it over the summer the whole bolt was out of the case just sitting in the lower pan and the hole in the case was probably almost 3 inches. Reverse acted fine without issues in the grass, but it skipped a little going forward. Ended up putting a new chain on because it had a locked up link.

I guess my husband is going to look it all over (probably tuesday)and try red loctite. We aren't going to get another outer case yet unless we have to. Figured we would try to repair the one that's on it to make sure the bolt stays put. They are just to expensive to keep going through!
 
A couple of bucks said:
Just brainstorming here... Are the bearings associated with that shaft in A-OK shape? I'm picturing vibrations from a bad bearing, helping that bolt to vibrate loose. I'm just looking for an underlying problem.
Click to expand...

jenfred10 said:
That's interesting that you ask that. I believe one is fairly new. The one on the chain case side maybe if I have the right? There hasn't been any weird noises,but he thought he started to feel some vibration here and there kind of like a belt starting to go bad. The belt looks like brand new,and only has 200 miles on it though.
He's really not sure if it was a vibration it was so minor.
Click to expand...

I'd continue digging into this one if no other obvious solution is apparent. A vibration, even if minor, is an indication that something that spins is out of whack. I haven't done much with the reverse chaincase, but it may be possible that a bad bearing, or perhaps even a bent axle, could cause the chaincase end of the axle to spin in a bit of an elliptical pattern, or even just off center. If so, is it possible that the spring cup (held in place by that bolt), comes into contact with something inside the case, thus causing enough drag on the cup to loosen the bolt/cup assy? Once the bolt is loose and the parts start to back out, they eat into the case with the help of the spring pushing on them. Again, I haven't done much with these and I don't have an example here to look at, but I would be suspicious that a properly tightened bolt isn't just backing out on its' own, something else may be in play to loosen it besides oil in the locktite, especially after only 200 miles.
 
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