Lightweight rear hub question

Information relating to the Matchless G2 or AJS Model 14 250cc Lightweight
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clanger9
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Lightweight rear hub question

Post by clanger9 »

I'm hoping someone can advise on how lightweight rear hub bearings are supposed to go together...

As it's a roller bearing hub, I thought it would be a bit like a modern bike hub where the step on the shaft is exactly the right width to butt up against the bearings. However, with the bearings driven properly home into the hub, the shaft still "floats" a bit i.e. the shoulder isn't tight up against the inner race of the bearings. This leaves me with the dilemma of "how tight to do up the inner nuts". Clearly I can't tighten them hard as it'll wreck the bearings.

The workshop manual doesn't show any spacer or anything in between the bearings, just the shaft.
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So, how do I set this up? Do I need to pack the step on the shaft to take up the slack, or do I just do up the inner nuts "gently"? I'm pretty certain the bearings are seated properly in the hub and everything else (i.e. speedo drive and brake plate clearances) seems to be OK.

Have I missed something?

Any advice appreciated. I don't want to mess up my rear bearings, especially as replacements don't seem to be available at the moment...
1989 Moto Morini Dart 350
1993 Ducati 750SS
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Ozmadman
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Re: Lightweight rear hub question

Post by Ozmadman »

Check that you have the shaft the right way round as it is not equal both sides. The inner nuts have to be tight otherwise the brake plate and speedo drive will be loose, anyway they will only tighten up against the spacer which in turn will push against the inner race so no damage will be done. Once it is altogether I think you will find it is fine. You can get bearings for these anywhere as they are a standard size as are the(slightly smaller) front
Paul
1960 Model 8
1974 Yamaha RD250B US Model 6 speed
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clanger9
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Re: Lightweight rear hub question

Post by clanger9 »

Thanks, Paul.

I think I've got the shaft the right way round, as the flats on the shaft are in the right place. i.e. longer bit on the brake side. The offset seemed all wrong with the shaft the other way round, although the diagram in the workshop manual seems to show it the other way around, with the longer bit on the speedo drive side (?)

What you say about the inner nuts makes sense, otherwise the brake plate and speed drive aren't fixed up tight. Still, if the inner races are under sideways load, won't that ruin the bearings?

The more I think about it, the more I'm thinking that maybe one of the bearings isn't seated fully home. That would explain what I'm seeing.
I think I'll dismantle it again and take some measurements...

Good to know the bearings are generally available - I'd only checked with the spares scheme. Do you happen to know what size they are?
1989 Moto Morini Dart 350
1993 Ducati 750SS
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Ozmadman
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Re: Lightweight rear hub question

Post by Ozmadman »

clanger9 wrote:Thanks, Paul.

I think I've got the shaft the right way round, as the flats on the shaft are in the right place. i.e. longer bit on the brake side. The offset seemed all wrong with the shaft the other way round, although the diagram in the workshop manual seems to show it the other way around, with the longer bit on the speedo drive side (?)
Think you are right there as I did mine a few years back and when I put it back on the bike I had loads of thread sticking out one end of the nut and hardly any for the nut on the other side. Had to take it all apart again and turn the shaft round!!!
What you say about the inner nuts makes sense, otherwise the brake plate and speed drive aren't fixed up tight. Still, if the inner races are under sideways load, won't that ruin the bearings?
yes you are probably right on hindsight. I do remember having an issue with mine with the bearings but can't remember what it was though, it was about 4 years ago now
The more I think about it, the more I'm thinking that maybe one of the bearings isn't seated fully home. That would explain what I'm seeing.
I think I'll dismantle it again and take some measurements...

Good to know the bearings are generally available - I'd only checked with the spares scheme. Do you happen to know what size they are?
no but I will have a look at my spare ones and measure them tomorrow. In the meantime you can get some from here, this is where I got mine from
http://www.ebay.co.uk/itm/KIT-of-2-REAR ... XQdm5RBE8u
Paul
1960 Model 8
1974 Yamaha RD250B US Model 6 speed
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Janet
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Re: Lightweight rear hub question

Post by Janet »

I have no idea which way round the shaft is supposed to be but on my spare hub, the distance from the bearing to the end of the shaft is approximately 2 5/8"" on the brake plate (near)side and is 3" on the speedo drive (off)side. The shaft in the wheel on my bike seems to agree with this as it also sticks out further on the offside than on the nearside. If this is wrong, I've go some more work to do. Or maybe I should leave it since it seems to be working.

Regarding the bearings, did you mention to the spares people that they still show as being in stock on the website? It may be helpful to let them know so they can remove the listing. Alternatively, they may have received a new batch after you enquired.
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Stuoyb
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Re: Lightweight rear hub question

Post by Stuoyb »

043298 Rear wheel bearing is back in stock.
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clanger9
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Re: Lightweight rear hub question

Post by clanger9 »

Ah, excellent! They showed out of stock when I checked before.

I think I'll dismantle the hub again and do some measurements. Most likely one of the bearings isn't fully home...

[UPDATE]

Yes, the chain side bearing wasn't fully home - there was a high spot in the hub. All fixed now, nuts all done up tight :)
1989 Moto Morini Dart 350
1993 Ducati 750SS
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