Rear Wheel Help

[3Phase]

Any oil wet or misting?

Rev,

Is the output shaft bearing in the Middle Drive still good or is has it started to fail or come loose and the output shaft is trying to crawl out of the drive, pushing the u-joint and drive shaft back and sideways?


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[BA80]

I was just out looking at some swing arms I have in the garage and at my bike to see what could cause the problem you are having assuming the middle drive is good.. There are only 2 things I can see that might cause it.

#1 - Your engine mounts are worn and are letting the engine drop down in the rear too far. That u-joint is bolted to the middle drive and depends on the rubber engine mounts to keep it centered properly in the drive line tube which is mounted to the frame via the swing arm bearings. Check your engine mounts for wear. Particularly the rear mounts that the long bolt goes through that your foot pegs are mounted with. Be sure the rubber is in good shape and that bolt is centered good in them.

#2 - The bottom of the swing arm somehow got caved in right there at the u -joint and is bent up into it.

[TheRev]

How would I check that? I will go out in a few minutes and wiggle the U Joint and see if there is any play.

Rev,

Is the output shaft bearing in the Middle Drive still good or is has it started to fail or come loose and the output shaft is trying to crawl out of the drive, pushing the u-joint and drive shaft back and sideways?


.

[TheRev]

I was thinking the same thing about the rear of the engine. What would be the best way to check those mounts? Take the foot pegs out, remove the long bolt and remove the mounts? How would I know if the middle drive is bad? When I spin the U Joint it spins nice and smooth by hand. So I am assuming it is fine.

I was just out looking at some swing arms I have in the garage and at my bike to see what could cause the problem you are having assuming the middle drive is good.. There are only 2 things I can see that might cause it.

#1 - Your engine mounts are worn and are letting the engine drop down in the rear too far. That u-joint is bolted to the middle drive and depends on the rubber engine mounts to keep it centered properly in the drive line tube which is mounted to the frame via the swing arm bearings. Check your engine mounts for wear. Particularly the rear mounts that the long bolt goes through that your foot pegs are mounted with. Be sure the rubber is in good shape and that bolt is centered good in them.

#2 - The bottom of the swing arm somehow got caved in right there at the u -joint and is bent up into it.

[TheRev]

So I went out and rotated the U Joint. There is absolutely no play either horizontally or vertically. So I am assuming that the middle drive is good.

Rev,

Is the output shaft bearing in the Middle Drive still good or is has it started to fail or come loose and the output shaft is trying to crawl out of the drive, pushing the u-joint and drive shaft back and sideways?


.

[TheRev]

I went out to look at the swing arm. I took some pics. Basically the u joint has been hitting the swing arm on the left and right sides not the top and bottom. So I would assume the engine is right where it is supposed to be horizontally. Is that a good assumption? I have included some pics of the gouges in the swing arm.

I was just out looking at some swing arms I have in the garage and at my bike to see what could cause the problem you are having assuming the middle drive is good.. There are only 2 things I can see that might cause it.

#1 - Your engine mounts are worn and are letting the engine drop down in the rear too far. That u-joint is bolted to the middle drive and depends on the rubber engine mounts to keep it centered properly in the drive line tube which is mounted to the frame via the swing arm bearings. Check your engine mounts for wear. Particularly the rear mounts that the long bolt goes through that your foot pegs are mounted with. Be sure the rubber is in good shape and that bolt is centered good in them.

#2 - The bottom of the swing arm somehow got caved in right there at the u -joint and is bent up into it.

[BA80]

I was thinking the same thing about the rear of the engine. What would be the best way to check those mounts? Take the foot pegs out, remove the long bolt and remove the mounts? How would I know if the middle drive is bad? When I spin the U Joint it spins nice and smooth by hand. So I am assuming it is fine.

You should be able to visually check them, you'll be able to see if there is a problem. You could put a jack under the rear of the engine and see if you can raise it enough to stop the rubbing.

One other thought I had was if you or the PO has had the driveshaft pulled out of the u-joint it may not have gotten snapped back in there straight and is wobbling. trbig had that happen along the road in Tennessee a couple years ago when he pulled his middle drive to check it.

[BA80]

Just saw the pics you posted. It looks like that u-joint is either wobbling in there like I said, or is coming apart or the wrong joint.

How about a pic of the u-joint.

[BA80]

I just had another thought, it would be too easy though.

The only thing I can see that COULD rub there is the bolts that hold the u-joint to the middle drive. Did you have the bolts in with the heads on the u-joint side or the MD side?

If you have them in with the heads on the MD side, the tips of the bolts are hitting the swing arm.

[TheRev]

I believe the bolts are not the originals. Perhaps the bolts are the problem. Here is a pic of the U Joint.

I just had another thought, it would be too easy though.

The only thing I can see that COULD rub there is the bolts that hold the u-joint to the middle drive. Did you have the bolts in with the heads on the u-joint side or the MD side?

If you have them in with the heads on the MD side, the tips of the bolts are hitting the swing arm.

[TheRev]

I took the shaft out when I dismantled the bike. What do you mean by snapped back in? I don't remember hearing a snap when I pushed it into the u joint. Are you supposed to push the shaft onto the u joint and then put the wire clip on or push the shaft in with the clip in place? When I rotate the u joint there is no vertical or lateral movement.. It seems very solid.

You should be able to visually check them, you'll be able to see if there is a problem. You could put a jack under the rear of the engine and see if you can raise it enough to stop the rubbing.

One other thought I had was if you or the PO has had the driveshaft pulled out of the u-joint it may not have gotten snapped back in there straight and is wobbling. trbig had that happen along the road in Tennessee a couple years ago when he pulled his middle drive to check it.

[bikerphil]

There shouldn't be nuts on the back of those 4 bolts, the u joint itself has it's own threads. Not the correct bolts either.

[BA80]

I took the shaft out when I dismantled the bike. What do you mean by snapped back in? I don't remember hearing a snap when I pushed it into the u joint. Are you supposed to push the shaft onto the u joint and then put the wire clip on or push the shaft in with the clip in place? When I rotate the u joint there is no vertical or lateral movement.. It seems very solid.

What I mean by snapped back in is there is a snap ring around the splines on the driveshaft that snaps into a groove inside the u-joint receptacle. It has been discussed in the 750/850 final drive swap that this actually does nothing but make it more difficult to install the driveline.

If the driveline doesn't slide completely into the u-joint it will wobble, vibrate and booger up the splines on both.

You say those aren't the original bolts in the u-joint? Are they longer than the originals?

I see you have them running with the heads toward the MD. Try running them the other way. With the heads at the u-joint side and the nuts on the MD side.

[TheRev]

So do you think this is my problem? Do I take the nuts off and use the bolts or try to find the origionals?

There shouldn't be nuts on the back of those 4 bolts, the u joint itself has it's own threads. Not the correct bolts either.

[BA80]

There shouldn't be nuts on the back of those 4 bolts, the u joint itself has it's own threads. Not the correct bolts either.

You know, your right Phil? I had to go look because it's been a while but THERE IT IS!

Those bolts are hitting because they don't stick back that far.