commando/amc gearbox options/compatability

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I'm pretty sure any AMC box will fit into a commando and the internals are all similar, except for the mainshaft. On my bike, I use a TTI gearbox with a single row primary chain with a Manx clutch. The TTI is intended to be used with the diaphragm clutch, so the mainshaft is too long. I get around it by using Jawa Speedway engine sprockets floating on a splined carrier I had manufactured. It depends on what you use the bike for - I would not do that on a road bike.
sounds like a shorter main shaft gb ina commando would work then with an atlas clutch, tho dunno if the suitable single row(?) chain comes in diff lenghts..

then a simple cover could be fabbed but prob the atlas chain runs in oil? like the commando

have no clue about racing or custom parts options
 
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I'm pretty sure any AMC box will fit into a commando and the internals are all similar, except for the mainshaft. On my bike, I use a TTI gearbox with a single row primary chain with a Manx clutch. The TTI is intended to be used with the diaphragm clutch, so the mainshaft is too long. I get around it by using Jawa Speedway engine sprockets floating on a splined carrier I had manufactured. It depends on what you use the bike for - I would not do that on a road bike.

Not quite right, the AMC box which is the one used on Norton Atlas, Dominator and Commando has a different shell from those used on Matchless and AJS motorcycles. The internals are the same.
John in Texas
 
might be an easy fix for use of some non commando boxes?
http://www.clubmanracing.com/beltdrivesnorton.php
To mount a Commando clutch to the earlier gearboxes either the mainshaft must be changed to the later version or a modified Commando clutch center must be used.

-----------

modified Commando Clutch Center
The simplest and least expensive way to fit a Commando clutch to a Featherbed gearbox - $105.00

hmmm.. - "Clutch Centre, Atlas Mainshaft, Commando Clutch Conversion"
http://www.britcycle.com/Products/06/06_3979a.htm

anyone looking out for a fastback/commando mainshaft - part# 06.0384,
if you don't know the diffs, or what to look out for, sometimes they show a part # on ebay, tho ebay ads are often wrong

sez here there are 4
https://www.nortonownersclub.org/
https://www.rgmnorton.co.uk/dept/shafts_d0157.htm

MAINSHAFT COMMANDO GEARBOX, 9 7/16" LONG
PART NO
060384


MAINSHAFT PRE COMMANDO AMC GEARBOX, 9 1/4" LONG

PART NO
040001

MAINSHAFT AMC MANX GEARBOX, 8 15/16" LONG
PART NO
040001M

MAINSHAFT SHORT RACING, AMC G50 ETC 8 1/2" LONG
PART NO
4A-094

https://www.nortonownersclub.org

Attached table shows choice of internals.
https://www.nortonownersclub.org



some 5 speed stuff
https://www.accessnorton.com/NortonCommando/5-speed-gear-box.15058/

https://www.accessnorton.com/NortonCommando/5-speed-gearbox.3364/
 
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Many of the pre-1960 Matchless and AJS had AMC boxes which can be used in a commando, if you change the mainshaft or use an early clutch .. If you don't change the mainshaft in the earlier box and use the diaphragm clutch, there is an alignment problem of about 6mm.

this sounds like a straight atlas to commando clutch swap,
https://www.accessnorton.com/Norton...do-primary-chaincase-cover.23876/#post-351187

i think the above quote indicates an atlas g/b can be used in a commando using an atlas clutch? with cdo primary cases?

any more details?
 
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Rest assured Atlas shell is identical to Commando except the Atlas shell does not force ya to fart with the stupid thick wedge spacer, just fit gearbox align holes, shove in bolt nip up done. Atlas shells are about 1/2 cheaper last time I shopped 15 yr ago. I've a Qualfe shell that Icrken Canaga did a bolt hole weld up repair for me. I like its beefy looks. Did not use as eventually afforded a New Zealand ITT 4 spd.

So far no cost effective way to restore wallowed out AMC bearing bores so eventually will run out. About 15 yr ago called world wide looking for Commando gb to learn the major shops each had a big pile of cases that by now likely scraped out. The only place I know that still has piles of good Commando and Atlas shells, plus other Commando items, is Baxters Cycles.
there is. but they are in England. Havant to be precise
 
All inner gearbox covers are the same for Atlas, Commando, N15/P11.
You cannot use the very early Atlas inner gearbox that had not the dowel spring hook location to stop the KICKSTART RETURN SPRING.
The spring was located directly into a hole in the inner gearbox covers and the spring was thin.
Ciao.
Piero
 
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All inner gearbox covers are the same for Atlas, Commando, N15/P11.

You cannot use the very early Atlas inner gearbox that had not the dowel spring hook location to stop the KICKSTART RETURN SPRING.
The spring was located directly into a hole in the inner gearbox covers and the spring was thin.
Ciao.
Piero
I think all atlas gearboxes had that type of return spring right up to when they stopped production and changed to commando ,but I'm not certain
I assume the earlier return spring was not as good as a commando one?
 
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I think all atlas gearboxes had that type of return spring right up to when they stopped production and changed to commando ,but I'm not certain
I assume the earlier return spring was not as good as a commando one?
Hi.
Not at all, only the early year.
Piero
 
Hi.
Not at all, only the early year.
Piero
I wouldn't know
I have an atlas gearbox that I thought was from a late model atlas gearbox but maybe an early one
This has the spring retained with a hole
 
I wouldn't know
I have an atlas gearbox that I thought was from a late model atlas gearbox but maybe an early one
This has the spring retained with a hole
and spring has less coils and is thinner than hook type
 
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