82 GS750e Rear Wheel Bearings Keep Failing

[Gort]

My 82 GS750e project is having an issue where I've now had the disk side rear wheel bearings fail 3 times, each time lasting less than 100 miles. I decided to replace them in the first place because the PO was the original owner, couldn't recall ever having replaced them, and the bike has 35k mi on it.

The chain and sprockets are new, the tires are new. Chain is tensioned to 1 1/4" on the center stand, at 6'4 I weigh about 200lbs, I don't know if this is too tight, but from what I've read on here I think that's right? I've read overtight chains can contribute to this kind of issue.

PO had put a 16" rear wheel on instead of what I believe is the stock 17" from what the manual says. Originally the disk side spacer that goes between the caliper and swingarm was missing, and had been replaced by washers. So, after the first bearing failure I hunted down an OEM spacer thinking maybe the washers had been off by enough to cause side load, but no dice. I noticed a little scoring where the disk side wheel bearing sat on the axle, so I went ahead and replaced the axle as well just in case. Still no dice, failed again.

Every time I've replaced the full set of bearings, even the sprocket one. I cleaned the wheel thoroughly and seated them using the threaded rod and washer method, so the inner races aren't being touched during install. Castle axle nut, caliper bolts, and everything else has been torqued exactly within manual specs.

Every time, it is the disk side rear wheel bearing that is failing, in one case, it disintegrated when I took the wheel off and the top hat spacer came off.

The bearings themselves have been AllBalls.

This is making me crazy. At this point all I can think of that could be causing this is that there's something wrong with the wheel hub itself but as far as I know it was fine previously so somehow it must have been damaged in the interim, I'm unknowingly botching the install, or the differently sized rear wheel is a problem somehow.

Any insight or advice into what to do next would be greatly appreciated. Thanks!

[Rijko]

I have seen something like that before, in that case
the spacer between the bearings was missing.

[storm 64]

I've had that problem on my 81 1100e once, blown out rear wheel bearings. It sidelined me in Ripley West Virginia believe it or not. I had a friend drive 3+ hours to come get me. I replaced all the bearings. I remember I had to split the outer race to get it out. It never happened again but I didn't really trust it on long trips. I kept closer to home so my friend wouldn't have to drive as far to pick me up.

Is it possible the inner spacer is mushroomed or deformed somehow that it's putting a sideload on the bearings when tightening the axel? Do you have any machinist friends that could assist you putting the new bearings in? Something screwy is going on.

[Redman]

https://cdn.partzilla.com/cdn-cgi/im...Q-1329caba.png

[Gort]

Is it possible the inner spacer is mushroomed or deformed somehow that it's putting a sideload on the bearings when tightening the axel? Do you have any machinist friends that could assist you putting the new bearings in? Something screwy is going on.

The inner spacer is the only part of the rear wheel assembly I haven't devoted any special attention to aside from cleaning. I'll take a closer look when I get the bike back up one the center stand, but I don't recall it being outside of what I'd expected. If it is deformed it's subtle, but I know small abnormalities can cause big problems.

Sadly, I just moved, so my friends with the skills to observe and help are over 1k miles away now :\

[Gort]

https://cdn.partzilla.com/cdn-cgi/im...Q-1329caba.png

Yeah I've got the service manuals and have consulted the fiche to ensure I have all the appropriate parts configured in the correct way.

[Cipher]

Allballs?
Go to the nearest industrial bearing vendor near you
Have the oldest guy x ref with a high quality bearing

Also

Are you inserting the bearing to correct depth? If off a spacer may be loading the bearing on one side?
Part# 08133-62047 Desc B1 20X47X14 BEA -SU USD Price 31.12
Part# 09262-20042 Desc B1 20X47X14 BEA -SU USD Price 26.32

I copied this as I suspected having a rh and lh bearing specified means a difference in seals and possibly rpm and other load specs

[RichDesmond]

Are you sure all the critical dimensions (there's a bunch) are the same between the two wheels?

[Gort]

Are you sure all the critical dimensions (there's a bunch) are the same between the two wheels?

I am not. This is one thing I was worried about. I'm uncertain how to find this information, though, as I can't find anything about it in the manual.

I've got the 750e, as far as I can tell the wheel came off a 750l. It's a mag and the the sprocket and disk appear to be identical to those on the stock E wheel, but I can't be more precise than eyeballing the fiche and images of the two. I was hoping someone here might know haha.

[Gort]

Allballs?
Go to the nearest industrial bearing vendor near you
Have the oldest guy x ref with a high quality bearing

Also

Are you inserting the bearing to correct depth? If off a spacer may be loading the bearing on one side?
Part# 08133-62047 Desc B1 20X47X14 BEA -SU USD Price 31.12
Part# 09262-20042 Desc B1 20X47X14 BEA -SU USD Price 26.32

I copied this as I suspected having a rh and lh bearing specified means a difference in seals and possibly rpm and other load specs

Thanks! I'll definitely make sure I get the next set this way. Really appreciate the suggestion.

As far as inserting them to the correct depth, there's an inner lip/shelf on each side I was under the impression was the natural seating point on this wheel. If that's not correct, it could be the issue, but it looks like the inner spacer would float free and not make contact if they were any shallower. That said, I have no doubt if they are too deep that might cause the spacer to be loading one side as you said. I'll recheck what the manual says, but that assumes it's the same for this wheel as the stock.

[Cipher]

I am not. This is one thing I was worried about. I'm uncertain how to find this information, though, as I can't find anything about it in the manual.

I've got the 750e, as far as I can tell the wheel came off a 750l. It's a mag and the the sprocket and disk appear to be identical to those on the stock E wheel, but I can't be more precise than eyeballing the fiche and images of the two. I was hoping someone here might know haha.

I had the depth thing happen on my front wheel years ago
Had to beat a new bearing to death to get it out.

Also the bearing oem is odd. I can't decipher or find load ratings but one is a Koyo 6204 z with a metal seal on one side The other is an NTN 6204 lu it has a rubber seal possibly two.

[Brendan W]

Could it be that the 16" hub is different and that the spacer did not go missing but was ditched because it was now the wrong size for the new setup and the washers were a measured shim pack?

[Gort]

Could it be that the 16" hub is different and that the spacer did not go missing but was ditched because it was now the wrong size for the new setup and the washers were a measured shim pack?

That is entirely possible since I don't know what the measured differences are, if any, between the two wheels.

That said, the bearing failures started with the washers in place. The washers were all of varying diameters and thicknesses, so it was definitely an ad-hoc addition one way or the other, which is why I had originally thought the PO had simply lost the original. There was only about a .5-1mm difference between the washers and the OEM spacer.

Given the washers differing inner and outer diameters, I had been hoping the resultant difference in where the load was being taken/transmitted through them was the culprit.

But now I'm wondering if the spacer itself is original to the stock wheel and not the 16", since PO clearly improvised rather than getting OEM replacements. Could be it's longer than what would be in the 16" wheel, making the standard bearing seating to the inner lips too deep.

[Maddevill]

Regarding #4 in the parts diagram. Does the inner spacer have an actual flange in the middle like in the picture ? If so, are both
end lengths identical ? Maybe its installed backwards.

Mad

[Rijko]

Check spacer clearance from both sides, stick pinky finger through
bearing and see if there is a gap and spacer is free to move.
That would not be good.
And both bearings should rotate freely.