Model 30 gearbox identification

[DerekAJS30]

I am just starting a rebuild of an AJS Model 30 (1957). Can anyone advise me how to identify if my gearbos is a "burman" or "AMC" ? There seem to be differences when it comes to ordering parts.

[g80csp11]

it will be a AMC box , if you check the archives section you can see part numbers for the parts you require or if you are in a hurry

or a shorter link http://archives.jampot.dk/book/Spares_l ... _Twins.pdf

[DerekAJS30]

Excellent thank you. I'm new to AJS twins so its a bit of a learning curve.

[G15 Roy]

If you post the gear box number here then it will be easy to confirm the type you have but for 1957 it should be an AMC.

[SPRIDDLER]

Excellent thank you. I'm new to AJS twins so its a bit of a learning curve.

Welcome Derek.
You'll also find strip and rebuild info in the Archives (link below) if you choose 'Technical' then 'Transmission', then AMC or Burman depending upon which gearbox you have.

http://archives.jampot.dk/

[g80csp11]

also check our own archives https://www.jampot.com/archives.asp

[g5wqian]

hi Derek ,
the 57 would be an amc gearbox and should have alloy primary chaincase along with the slimmer rear shocks which have a "fork" on bottom and eye on the top for fitting .

the amc box has a different filler cap which is easily identified as it has 2 holes in it for mounting screws .

the pre 57 burman gearbox has a large screw in filler plug , youll probably use a GB52 version .

pre 57 will have "jampot" rear shocks ie the fat ones .

amc gearboxes were popular for racing on most british makes and still are .

burman boxes are good in their own right too , my model 30 is 1956 and has burman GB box , works great for me .

i would think it is possible to have a very early 57 bike which has tin primary case and burman box but i guess these will actually be 56 models sold in 57 and not the actual 57 model .

hopefully you can identify which box you need on your model 30 and progress to get it on the road etc .

they are great bikes , lots of torque and go like a rocket and sound great with a deep exhaust tone compared to the tinny sounding triumph or bsas .

look forward to hearing youve been out on it sometime .
cheers
ian

[Duncan]

i would think it is possible to have a very early 57 bike which has tin primary case and burman box but i guess these will actually be 56 models sold in 57 and not the actual 57 model .

A 1957 M30 used a one year only pressed steel primary chain case, it has a shallow dome as the shock absorber moved to the clutch. An alloy case can be retro fitted but you need to modify (reduce) the crankcases around the inlet camshaft cap to give clearance.

[DerekAJS30]

If you post the gear box number here then it will be easy to confirm the type you have but for 1957 it should be an AMC.

Hi G15 Roy - The gearbox number is M7114

The bike has an aluminium primary chain case

[DerekAJS30]

Thanks to everyone for thier technical knowledge. It's a lovely bike and although i like its "patina" and much of it looks original, i have already found a few simple but important bodges. I live in Devon so it needs to be reliable if i'm cruising the moors so i think a total rebuild is appropriate. Fun too researching the bike and conversing with you guys. My other bike is a Trident T160V which is a totally differenty animal.