I'm in the middle of rebuilding my gearbox for the 16H, and one interesting thing I noticed is that all 3 ball bearings in it are the same as fitted to Norton Dominator and Commandos, so therefore easy to get. I spoke to Nick at Andover Norton and they even do the main shaft sleeve gear bearing with a seal one side.

The felt seals look good but does anyone know where I can get these from? Thanks

email (option): horror@blueyonder.co.uk

What felt seals do you mean Dave? Do you know the part number?
My nos main shaft sleeve gear bearing was sealed in one side!

Hi Kostas, I don't have part number and I can't see them in the exploded gearbox diagram I have (which is the one on the WD Norton website)
But here are pictures of them;





2 felt washers on the clutch actuating rod under the hexagon shaped cover.



2 felt washers under the rear gear lever arm 1 inside the hole and a larger diameter 1 on top.






A fibre washer in the recess in the kickstart bush. This one is broken but will do if I can get a replacement.

email (option): horror@blueyonder.co.uk

The clutch operating spindle needs as much felt as you can cram in there. The felts are usually OK.

Mine dribbles round the kickstart shaft but I think that I lack the fibres washer that you have.

The bearings are indeed the same as later Norton boxes but as Norton man, you'll know that the inner diameter of the sleeve gear bearing is specially ground. Any from AN will be OK but not from a bearing supplier based on the number.

The Doll's head has much in common with the boxes used on later Nortons. It's strange really that it was called the 'AMC' box as although it was made under their ownership it was really a development of the Norton / Sturmey-Archer box (with an inferior clutch operating mechanism !)

Apart from bearings and bushes, any wear is most likely to be in the bronze mainshaft thrust washer - Andy Molnar lists those amongst his Manx bits if you need one.

Hi Rik, do you know where I can get replacement felt washers in these sizes? Thanks

email (option): horror@blueyonder.co.uk

RLS 9 Z 1 1/4" is the large bearing with the non standard internal diameter. I think Triumphs use the same bearing, but I'll have to check.

email (option): rvanmeel@wanadoo.nl

Horror, Russells have quite a lot of 16H gaskets and seals. Otherwise perhaps RGM or Bantam John - the usual suspects !

Ok, thanks Rik. I haven't phoned around, just didn't know if anyone had bought them recently.

There's no problem with the bearings Rob, Andover Norton do them all.
The main sleeve gear bearing with the seal on one side is A2-316 (040098 without it)

Nick at AN seemed to think the Commando/Dommie gearbox cluster would fit in a Dolls Head box. The parts aren't interchangeable, but the whole cluster can be used. Just shows the box has stayed the same since the 30's and was able to handle a lot more power than 14bhp

email (option): horror@blueyonder.co.uk

You can't use the later cluster as-is because the Doll's Head has no positive location (nut) on the end of the mainshaft so any end-float has to be accomodated by the thrust washer. The problem here is that the dogs on the sleeve gear are bigger on the AMC box so no clearance for a standard thrust washer and additionally there is no surface-ground hardened steel cap in the sleeve gear for it to bear against - Have a look at the end-face of a Commando sleeve gear, it's quite roughly machined.

The box can certainly be assembled but to work properly would require some machining.

The early box is better engineered than the later ones - it has rollers in the sleeve gear instead of bushes and a Manx box with a proper bearing in the end cover (no kickstart) is a lot stronger than a roadgoing Commando.

I've had no luck getting the felt washers etc but I think I've sorted it with O rings. I still need the fibre washer for the kickstart bush, but I will make one if I can find a fibre washer big enough.

One thing that worried me, The main sleeve gear bearing has a large shim over it before the sleeve gear goes through it. This shim has a bigger inner diameter than the sleeve gear and fits into the bearing around the inner bearing race. With this fitted, how does oil get to this main bearing? Especially if a liquid grease is used? The smaller bearing at the other end of the main shaft also has a shim covering it. There is no other way for oil to feed these bearings except past these shims. I've put them in the box, but I wondered if leaving them out might help lubrication?

email (option): horror@blueyonder.co.uk

Dave I don't think the Norton box is designed to run with grease like the Burman box's. I also think those shims are a sort of baffle to reduce the flow of oil through the bearing. Have you thought about replacing it with a sealed bearing and just remove the inner seal? You can then forget about felt seals.
I always do that if I can. It certainly reduces the oil pool under your bike. Ron

email (option): ronpier@talk21.com

Hi Ron, yes I have replaced the main bearing with a one sealed on one side which is the same as the one that came out. I see no reason why the gearbox shouldn't be quite oil tight, but it is worrying when oil can't get to the bearings because of these shims.
I'm glad you said it doesn't take liquid grease as it wasn't sounding right to me. I've heard of people putting all sorts of oils in these boxes, but as we discussed earlier, it's very similar to a Commando box with less strain on it, so I would have thought an EP 80/90 the same as the later boxes would have been fine. What do you use in yours?

email (option): horror@blueyonder.co.uk

Hi Horror...It should be noted that EP gearbox oils have viscocity ratings measured on a different scale to those of engine oils and as such they are not as 'heavy' as might be thought. An 80/90 EP oil equates in viscocity to an SAE 40 engine oil.
EP or extreme pressure gearbox oils also have a high additive content which includes chemically active sulphur, phosphorous and chlorine amongst others.
These help to dissipate heat, prevent corrosion, inhibit 'foaming', protect against localised extreme loadings etc.
However, these additives can be corrosive to phospher bronze, copper and other non ferrous materials. This effect has been reduced to a degree with more modern oils but has not been eliminated so use of EP oils should be considered with caution.
I am surprised the Commando had this type of oil specified as standard..though Norton may have traded off 'lubrication under high pressure conditions' against 'bush deterioration over a period of time' as the box was pretty much at the limit of it's capabilities handling the power delivered by the Commando engine. I believe its designed maximum power transmission capability when initially produced for the Dominator was 45 BHP, though modifications were made to improve strength for the Commando. When I worked in Terry Hobbs Motorcycles we used these boxes in pre 65 scramblers with full race Triumph engines and the mainshafts used to bend after a few meetings!....Ian

email (option): ian@wright52.plus.com

Thanks Ian, I would be interested to hear your opinion of the shims that cover the bearings that I've mentioned above, please.

email (option): horror@blueyonder.co.uk

Hi Horror..BSA gearboxes have similar shims..Whilst they serve to reduce the passage of oil they are by no means oiltight and enough oil seems to get by to keep the bearings lubed. The inner cover bearing is inside the gearbox in the BSA box, so passage of oil through the bearing isn't really an issue anyway. Not so with the main bearing where any oil that works its way through will leak out. I wonder if their actual function is to stop the bearings churning up the gearbox oil rather than preventing it leaking out?...Ian

email (option): ian@wright52.plus.com

Ok thanks Ian, they are obviously meant to be there and I've put them back, I just couldn't think of a reason for them. I've just rebuilt a rigid Triumph box for someone which has a very similar layout, the same as a Dommie/Commando box, and none of them have these fitted. I've made sure the bearings are well oiled before the shims go on, but I would say it had disaster written all over it

email (option): horror@blueyonder.co.uk

Don't worry about it Dave! When those shims are fitted to the outside of the bearing and even with felt seals fitted. The oil will still get past and make a puddle under your bike. It always puts me in mind of our transit tipper's front wheel bearings that run for maybe 50,000 on one grease up, and they are abused, over loaded and running in quarries etc. Ron

email (option): ronpier@talk21.com

Hi Ron, The shims go on the inside of the bearings stopping the oil getting to them and there's no felt washers on the outside of them, a one sided sealed bearing is used.

I've just spoken to George Cohen from http://www.norton.uk.com/
He has told me to leave them out, but just make sure the mainshaft end float is no more than 5 thou by putting the shim under the bearing if necessaries. He has no idea what they are for either, and he uses Castrolease in the box. I am very happy to leave them out as it is asking for trouble as far as I can see.
Maybe the bearings were originally packed with grease, and the shim sealed the bearing on the inside keeping the grease in, is the best reason I can give.

The picture I have posted is misleading as the sleeve gear goes thought the shim them the bearing.

email (option): horror@blueyonder.co.uk

Did Doctor Cohen give you any treatment when you spoke to him?
I wasn't specifically talking about a Norton set up in my previous post. Just emphasizing how the oil can get through even when you don't want it too. Ron

email (option): ronpier@talk21.com

Yes I get your point, thanks Ron

I've just ordered some bushes from Russell's, and he says put the shims in and use engine oil in the box. The oil will get around without any problem (as Ron said)

There ya go....! Everyone has a different point of view

Oh and 5 thou is a joke.... I have about 1/4" end float..!! If I packed that much behind the bearing it would fall out the casing

email (option): horror@blueyonder.co.uk

You definitely need to phone Dr George for some therapy.
How else do you think the poor bloke is supposed to afford those Manx's and Aston Martins. Ron

email (option): ronpier@talk21.com

Five thou endfloat ? Edgar Franks says to investigate if endfloat exceeds 3/32" ! Obviously it should be less than that - barely perceptible and not really going 'clunk' if you pull on the mainshaft is about right !

The steel washer on the outside of the bearing doesn't need to be fitted if you're running a sealed bearing. It sits in a slightly deeper recess behind the bearing so it doesn't have a shimming function.

On high mileage Doll's Head boxes, the washer between the sleeve gear and the bearing has usually milled itself to a steel ring barely bigger than the shaft - and the boxes were still running.

In the late-war workshop manual, a spring steel or Belleville washer is shown on the other end of the mainshaft in the exploded diagram. As far as I'm aware, this doesn't appear in any of the wartime parts lists. It first appeared in the 1946 list (with the 'A' prefix numbers)/

I've yet to talk with anyone who has found one of these in a WD box and mine certainly had no space for one. I can't imagine where the space would come from.

I have noticed that even the humble M20/21 boxes..which have far fewer alternative 'exotic' uses than the Norton one, have jumped sharply in price lately..a sign of the times .. ..I've seen the Norton one sell for over a £1000 in the recent past, not so much if you need one to complete your Brough project I suppose....Ian

email (option): ian@wright52.plus.com

I think that's the problem Ian. With the exception of the internal ratios, the Norton boxes were in no way model specific. The WD stock has been plundered for years in order to keep the irrelevant posing tackle of a bunch of 'Promenade Percies' ready for track days.

I paid £150 for my box about eight years ago and thought that was lumpy as AMC boxes were around for half that !

H., Has your original shim not simply milled itself against the sleeve gear ? Why did you space behind the mainshaft bearing rather than between shaft and bearing where the instruction manual shows the bellville washer ?

I guess anything's possible Rik, although the shim doesn't look jagged on the edges which I would expect it to look like if it had worn away.

Everyone I spoke to said shim it behind the bearing.
The washer I put behind it was 75 thou (the thickest I had at that size)so I still have 20 thou to make up and that's without a gasket fitted. I was a bit worried about putting a plain steel washer in a position where it would wear away although I might have to yet. There's 2 thin shims at the end of the shaft already so if I put the washer between them they'll all spin together and the hardened shims will take the wear not the washer. 95 thou is about 2.5mm so I'll just have to fill up the gap where I can

email (option): horror@blueyonder.co.uk