AJS & Matchless Owners Club

Advice needed, I have a spare gearbox with my 1952 18s. The number on it is GB28L 54, from searching I understand this to be manufactured in November'54?
Can anyone tell me what model the 28 refers to and would the gear ratios be the same as my original?

Thanks

Steve

I assume your info (correctly as Nov '54) is from the list below, in which the 'Comments' state that 1954 350's will have GB18L54...........and 500's GB28L54:
http://archives.jampot.dk/technical/Tra ... umbers.pdf

The comments in the above document:
Hmm, well having typed the above I've just checked the number on the (almost certainly original) B52 'box on my '54 350 G3LS which is GB28C54 so the 'Comments' on the above list (which would mean it should be GB18C54) don't tie up with my 'box . However the Note 2 says that Competition models will also have GB28xxx
(I was tempted to delete the above confusing reply but the above link to the transmission number document may be of help if you haven't seen it).

The Instruction Manual for 1954 350 and 500 models: http://archives.jampot.dk/book/Owners_m ... ingles.pdf
shows that the internals were the same for both capacities but the 500's had a larger engine sprocket than the 350's:

Thanks for that, so it was originally a 350 box and internals are the same as a 500. I will get it stripped down