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Gear box oil seals and rear wheel spacers?

Submitted by dan_field on Mon, 29/08/2016
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Light Twins

I bought a couple of the small and large square seals to try to seal my leaky box, but having taken the cover off I can't see how to fit them, the big ones are loose on the shafts and I can't figure out where the small ones go? For now I replaced the o ring behind the bush in the gear change shaft, but left the seal next to the bush for the kickstart shaft in place, that was held in place by some kind of washer at the outboard end of the bush, for the moment I have just places an o ring inboard of the existing seal, the kicks rat is a little stiffer but it does return.

My second issue is the rear wheel isn't sitting centrally in the swing arm, do the washer/spacers go between the nuts and the swing arm or outside the swing arm under the wheel nuts?

Is there anywhere I can see exploded drawings? The parts book never has the picture you need!

Submitted by george_phillips on Tue, 30/08/2016

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If the rear hub assembly is similar to that of the singles the spacers are all between the swinging arm legs. I can't see the point of a spacer between the axle retaining nut and the swinging arm? I could scan n the rear axle exploded drawing for the '55 ES2/19/ if that would help, Dan.

Submitted by patrick_mullen on Tue, 30/08/2016

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Hi Dan,

I have an exploded drawing in the '1959-60 Maintenance Manual & Instruction Book for the unapproachable Norton Jubilee 250' - Publication 105. Problem is getting this scanner to work. Anyway lets try as it's hard to explain otherwise.

Patrick

Attachments jubilee-rear-wheel-pdf

Submitted by patrick_mullen on Tue, 30/08/2016

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Hi Dan,

That seems to have worked. Anyway the rear wheel is a bit like a bicycle wheel - it should slot in the swing arm in one piece, i.e the spacers are held in place by the two locknuts which are shown as 9/16" x 26 x 3/8". The short spacer 3/8" goes on the brake side and the long spacer 1 1/4" goes on the other side.

All this is on the inside of the swing arm. The two spindle nuts and washers then tighten up on the outside to hold the wheel in place.

Patrick

Submitted by dan_field on Tue, 30/08/2016

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Thanks guys. My question was about the thin spacers/ thick washers that are between the nut on either side and the wheel nuts. If I've understood this properly the two lock nuts on the axle but up against the inside of of the swing arm and the thin spacers are in fact thick washers that go on the outside! The exploded views don't show the swing arm!

Any thoughts on the gear box oil seals?

Thanks Dan

Submitted by patrick_mullen on Tue, 30/08/2016

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Hi Dan,

Yes the lock nut butts up to the inside of the swing arm and the 'thick' washer goes on the outside. According to the 1959 book the washer is part number 21816 and it is described as a plain washer 9/16" diameter X 10 S.W.G. - the same on both sides. I don't know how thick that is as all mine seem to be fairly ordinary washers.

I don't know on your later type gearbox O rings as all my machines are the early type. In case it is of any use to you there are THREE O rings in the gear change of the early box- one (medium size?) in the cover and two (very small) in the ' foot change ratchet shaft'. This is the shaft that comes through the centre of the gear change and holds the gear position indicator.

The large O ring in the kickstart on the early box is nothing more than an ornament - mine always weeps some oil if the gearbox is kept fully topped up.

Patrick

Submitted by dan_field on Tue, 30/08/2016

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Thanks Patrick

10SWG is about an 1/8th inchmine look a bit bigger than that, but I'll check tonight and see how it fits up, I'll also check the length of the real spacers!

I have an early gearbox cover from my Navi engine, the kickstart seals look the same size as the later ones but the later one seem to be better contained. The club sell square section seals apparently as an improvement but I cant see how they work if they are not a tight fit on the shaft.

How do you get to the seals on the gear indicator shaft?

Dan

Submitted by patrick_mullen on Tue, 30/08/2016

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Dan,

I've attached a scan of the EARLY gearbox as it's the only one I have. It does show the general idea at least. The small O rings are number 29; the O ring in the cover is number 28; kick start O ring is number 57. The later box must have something similar as I'm sure that it has the same style gear indicator screwed on the end.

Yes. The square section O rings have been around for quite a long time and I suppose they are a minor improvement but they do leak eventually. It's just the design is a bit basic.

Patrick

Attachments jubilee-gear-box-pdf

Submitted by dan_field on Tue, 30/08/2016

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Looks like you need to remove the selector mech to do the small seals, they can wait, there's not too much of a leak from there. And the good news is the new normal o rings I fitted to the kickstart and gear change shafts have significantly reduced the leaks, just the sleeve gear/ primary drive seal to do and that can wait too!

The wheel fits better too and I stopped fiddling with the footrest spacers and fiddled with the header mounting instead and I have clearance on the brake pedal and kickstart, just!

I also hooked up the generator and got 18 volts and a good charge at the ammeter. ..... Getting there!

Submitted by patrick_mullen on Wed, 31/08/2016

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Well done Dan. One small step for man etc.

You said the square section kickstart O ring you had was a loose fit on the shaft. I think you have been supplied with the wrong size O ring. I once bought some cheap O rings on Ebay supposedly to fit the Jubilee gearbox and the large O ring was the wrong size. The square section ones (expensive) I bought from the Club a fair while back were a good fit but generally speaking I now just use metric sized normal O rings as they are much cheaper and virtually as effective.

Good news that it is charging - I hope the 18 volts you got are not at the battery !.

Re the exhaust you said that you have only just got clearance on the kickstart side. That seems a bit odd as my kickstart clears the silencer no problem - maybe your kickstart is bent inwards?

Anyway well done - you will soon be on the road.

Patrick

Submitted by dan_field on Wed, 31/08/2016

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Hi Patrick,

18 v at the connection to the regulator rectifier after I'd doubled up the wires! The square section seals were from the club, which is disappointing. I've got a speedo cable to return as well which was way too long. But as you say modern o rings seem to work ok.

The kickstart looks straight but I'll check, I've got about 1/16th clearance at the moment!

One last question .... where does everyone mount the brake light switch?! Nowhere seems ideal!

Dan

Submitted by patrick_mullen on Thu, 01/09/2016

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Hi Dan,

The brake light switch on mine is mounted on a bracket attached to the mounting point for the rear (passenger) foot peg.

I don't know if that is original but it gives a neat fixing which seems to work effectively.

The kickstart on mine clears the silencer by at least 15mm.

Patrick

 


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