transmission variations

[seattle##gs]

There are a few changes that happened inside the box. I have a few gear sets and surplus gears. Is there anything written down about the different gears and how to spot them by number of teeth and measuring. I know a little bit about the AHB markings and the groove cut in the second gears as indicators. Some of these letter stampings are not clear.

 

[L.A.B.]

Commando or all AMC gearboxes?

 

[seattle##gs]

1966 to 1975

 

[L.A.B.]

The information I have is for the Commando.

1st., 3rd. and 4th. gear ratios didn't change although the sleeve gear and layshaft 4th. were changed from serial 128646 due to a revised tooth form so are dimensionally different...

New sleeve gear is larger then my old sleeve gear

I purchased a new sleeve shaft gear from a guy how had new old stock. I installed it but it fit too tight against the mating gear. It was very hard to turn. I remove the new gear sleeve gear and compared it with the old sleeve gear. Using a micrometer I found the new gear was larger in diameter...

www.accessnorton.com

...I don't know what markings - if any, the pre-128646 sleeve gear and layshaft 4th. had.

The 128646-on sleeve gear is marked 'AH', with a '6' or '9' on layshaft 4th.

Stronger 3rd. gears were introduced from serial 133488 and both marked 'AH'.

2nd. gear ratio changed from 18/24T to 18/23T from 306591 on the 850 Mk1A and later (Mk2, 2A & Mk3) models. Marked AHB with the grooved dogs. The original 18/24T 2nd.gear pair is marked 'AHA' by Andover Norton but presumably originally marked 'AH'.

The single (outer end) circlip sleeve gear 064991 was introduced as far as I know on the Mk2/2A, also marked 'AH'.

Twin circlip sleeve gear 065854 as far as I know, was introduced on the Mk3 and marked 'AH...3'.

Any gears marked RSxx are not genuine Norton.

 

[YukoNorton]

That is great info LAB. To have changes by engine number,as compared to listing of Layshaft 2nd gear - old type, or later type like from Fred's site. https://www.nwno.org/resources/OldBrittsWebsite/ob_1270.htm

Is there a simple list for the Commandos that has engine/gearbox changes by year or engine number?
I see Terry Macdonald has one like that for the Bonnevilles:

Triumph modifications/differentials by engine number 1963-83​

Terry Macdonald

triumphbonneville120.co.uk

 

[L.A.B.]

That is great info LAB.

Is there a simple list for the Commandos that has engine/gearbox changes by year or engine number?

Not that I know of.

 

[Atlas Commando]

I don't know how you do it L.A.B. My mental picture is you sitting at a huge desk surrounded by massive walls full of reference books and original Norton factory drawings, patents and work procedures. You get an e-mail request, stroll over to the correct shelf, pull out the desired material, adjust your glasses and provide incredible detailed information on 50 year old machines. I remain a fan!

 

[YukoNorton]

"...adjust your glasses and provide incredible detailed information on 50 year old machines....

I agree AC... perhaps L.A.B. is the man to create that technical reference for all...

"list for the Commandos that has engine/gearbox changes by year or engine number"

 

[L.A.B.]

I don't know how you do it L.A.B. My mental picture is you sitting at a huge desk surrounded by massive walls full of reference books and original Norton factory drawings, patents and work procedures. You get an e-mail request, stroll over to the correct shelf, pull out the desired material, adjust your glasses and provide incredible detailed information on 50 year old machines.

Actually, a very small desk and files are generally on computer plus I have a few 'Norton' books.

I agree AC... perhaps L.A.B. is the man to create that technical reference for all...

It's a possibility.

 

[YukoNorton]

The
Norton Commando Service Releases (Updated 06/13/22 )
I saw on Greg Marsh's site are 7 pages of notes on changes to the Commando, many with reference to engine/vin number:

Norton Commando Service Releases

Searchable database of Norton Commando services releases

gregmarsh.com

 

[Deckard]

A minor update, at s/n 147846 toughened kick-start pawls were introduced. Should have a little M marked on the side.

 

[YukoNorton]

A minor update, at s/n 147846 toughened kick-start pawls were introduced. Should have a little M marked on the side.

yup;

SERVICE RELEASE N50​

".. the latest pawl is stamped with the letter 'M' or a center pop mark. " GME - Norton Service Sheet N50 Norton Commando Service Sheet N50 gregmarsh.com

NATURE OF RELEASE: Intoduction of tougher kick start pawl

 

[GraemeH]

The 128646-on sleeve gear is marked 'AH', with a '6' or '9' on layshaft 4th.

Would this mean that if it is stamped '5' then it has the previous form of teeth so I should probably not mix and match 2 gearboxes?

 

[L.A.B.]

Would this mean that if it is stamped '5' then it has the previous form of teeth so I should probably not mix and match 2 gearboxes?

I don't know what the '5' is supposed to indicate but best to keep it with the matching sleeve gear if you intend to use it.

 

[o0norton0o]

Actually, a very small desk and files are generally on computer plus I have a few 'Norton' books.



It's a possibility.

You are clearly the "Alex Trebek" of Norton motorcycles

 

[L.A.B.]

You are clearly the "Alex Trebek" of Norton motorcycles

Being British I had to look that one up on Google as I'd never heard of him.

 

[o0norton0o]

Besides just looking him up and finding out that he was the host of the game show Jeopardy, he often would not only confirm an answer to a little known subject during the playing of the game, but add in even more obscure related facts just off the top of his head. He did this so often on so many different topics. He was clearly well read in so many different subjects that one could only conclude that he is a pretty smart guy...

 

[johnm]

This has some info.

 

[L.A.B.]

What Ashley says about not using a layshaft 4th gear with a number on it is wrong to me as both my Mk3 and spare Mk2/2A set of layshaft gears are marked 6 or 9 and my Mk3's sleeve gear is the Mk3 type with two circlips.
No mention of the four different sleeve gears fitted to the Commando.

 

[Hortons Norton]

Would this mean that if it is stamped '5' then it has the previous form of teeth so I should probably not mix and match 2 gearboxes?

View attachment 118305

If you look close at these two you can see the difference in the shape of the gear tooth.