Lightweight gearbox problem

[Ozmadman]

Thanks Paul for your detailed advice, I can see some light now at the end of the very long tunnel!

Sleeve gear, complete with bushes, came from Norvil Motorcycle Company 01543 278008, very helpful, I sent mine to Les Embrey, their parts specialist who said he would be able to sort me out. Came back very quickly, said to be used but I cannot see a single mark on it, £75 + VAT and postage. They are worth a try for other parts as well I'm sure as Les said he had unopened boxes of spares!

Looks like new, so you have a good spare too? hang onto it as they re like gold dust

My layshaft bush is rotating in the housing - will I be able to pull it out without removing the end cap etc?

Should be able to, I would clean up the recess and use some loctite bearing fit to make sure it doesn't turn. If you have trouble getting the right one (see my earlier post about the correct size) then the Norton lightweight box (Navigator I think) uses the same bush with the same part number. The only difference is that the Norton one has a small cut out in the top flange (for a locating pin to stop it turning would you beleive!) but it makes no difference for what we need to use it for.

Does the output shaft oil seal just prise out from the outside?

Yes, make sure when you put it all back that you get that sleeve for the oil seal the correct way round (flange facing the gear)

Once I get the box back together I'll review the clutch centre wobble and maybe order a 20 tooth sprocket, rear sprocket and chain making the transmission good to go.

Andrew enginnering did a 20 tooth sprocket if they are still trading, don't think club spares do one? but club spares have/had some 56 tooth rear sprockets ( there was one left when I ordered mine) which have been misdrilled in one of the holes, which evidently just needs opening up a bit? Only a fiver plus vat and postage.. Mine is a 55 tooth but a 56 will not make too much diference and be good as a spare should I ever use the bike ebnough to wear it out..

Need to check the swinging arm bearings and rear shocks as well.

If there is some play in the swingarm bearings normally you can fix it by loosening the cotter pin in the LH arm, putting a piece of wood against the pivot end of the RH arm with the other end against a wall or something immovable and then giving the pivot end of the LH arm a good whack, that should take up any play, then tighten up the cotter pin.

[Steve S]

Thanks Paul.

Layshaft bush came out with a simple twist and pull. Norvil told me about the Norton equivalent part number 048133 which needs a hole for the peg drilled, price is £15.50 plus vat each so a lot more money.

Will have a go at the oil seal now.

Gary has sold the last rear sprocket so I guess I'll continue with the slightly worn set up I have at present.

Cheers Steve S.

[Ozmadman]

Layshaft bush came out with a simple twist and pull. Norvil told me about the Norton equivalent part number 048133 which needs a hole for the peg drilled, price is £15.50 plus vat each so a lot more money.
Cheers Steve S.

Just looked at the picture (041289) in club spares and it still looks wrong (flange depth is miles too thin!!) pity as ours are only three quid, Russelll Motors list them but their prices are way out of date so who knows how much they will charge now? Andrew engineering lists them at £3.96 and on that basis I have ordered a couple for future spares, just hope they are the correct ones!!

[dodger]

I ordered two layshaft bushes and they arrived today.
Both have the wrong thin flange and are different heights, useless.
I have sent them back but I am disappointed the club are still selling duff items, after all the comments on here surely they know these bushes are no good

[Ozmadman]

I ordered two layshaft bushes and they arrived today.
Both have the wrong thin flange and are different heights, useless.
I have sent them back but I am disappointed the club are still selling duff items, after all the comments on here surely they know these bushes are no good

I will let you know how the Andrews ones shape up. If all else fails then I suppose at a push you could place a washer or shim etc under the flange to casing to lift it up a bit or an exact fitting washer (inside and outside diameter) on the layshaft but then with either of these options you would loose a little length where the shaft goes through the bush, not sure how much effect that would have.

[Ozmadman]

I ordered two layshaft bushes and they arrived today.
Both have the wrong thin flange and are different heights, useless.
I have sent them back but I am disappointed the club are still selling duff items, after all the comments on here surely they know these bushes are no good

They do know or they should. I had a lengthy thread on this years ago when I discovered the problem and contacted the spares dept to advise them. I was told that they had been made to the original drawings and spec but they are obviously wrong. My theory at the time was that the measurements on the original drawing for whatever the flange thickness should be has been transposed and machined using 0.00 of a millimetre instead of 0.000 of an inch. The incorrect bush (the flange thickness measurement) bore this out at the time. Later after Gary took over this came up again and he asked me if I could send him the correct bush so they could get some made. I would have done but the club could not guarantee that I would get my original bush back, only one from the new batch so I declined and that is how it has remained for a few years...

I think I have a good bush somewhere, I am willing to measure it and send in the details if that will help? or if Andrews come up trumps (2 ordered) I am willing to send one in as a pattern as long as I get one back

[Stuoyb]

It will be interesting to see what Andrew Engineering supply to you.
Andrew Supply this item to Club Parts Service and despite them being returned send them back as being "correct to drawing" ?

[Ozmadman]

It will be interesting to see what Andrew Engineering supply to you.
Andrew Supply this item to Club Parts Service and despite them being returned send them back as being "correct to drawing" ?

Yep I know, that's what was told years ago, will be interesting to see what the drawing actually says. if I can find both bushes I will measure them both and see what the actual difference is. Don't hold out much hope then for my ones from Andrews

[Ozmadman]

Can only find a new correct bush so here are the measurements (metric in brackets)

Flange thickness 0.178" (4.50mm)
I.D 0.625" (15.870mm)
O.D of bush minus flange 0.815" (20.68mm)
O.D of flange 1.012" (25.55mm)
Depth minus flange 0.452" (11.50mm)
Total depth inc flange 0.629" (16.00mm)

[Steve S]

My layshaft bush 041289 arrived today as well and it has a thin flange - measures 0.080".

As said above Andrew Eng have them at £3.96 and I note Russell Motors lists them at £8.50.

Norvil told me that part number 048133X is their equivalent at £15.50 plus VAT.

Will await Paul's update when he receives his.

Incidentally, do you all run your lightweights with a head steady? Where can I get one if it makes a useful difference?

Steve S.