Gearbox. Woes?

So, in a change from electrics, we have had an anorak moment with the gearbox. Reading part numbers (ZZZZZzzzzzz.....) and looking through the parts books, we find that the Squariel is supposed to be fitted with a Burman BA gearbox, with a part number staring with G106.

All not very interesting, until we see that our gearbox number is G107J51, which means it is a G107 gearbox built in November 1951, several months after Amelia was sold in sunny Leytonstone.

The problem is... the G107 is from a different Ariel with a different mainshaft and probably doesn't fit! what are the chances of finding the correct box? why did I buy a bike in bits?

But but but.... I feel a plan coming on. How will I figure out if it is OK? the folks on the AOMCC forum says it is all about chain alignment...

So, the plan is that we assemble the bike enough to check the chain alignment. I'm not sure if it will be the primary or the secondary chain, so I'm going to build up from the rear wheel to the primary cases and see where it goes...


To see how this story turns out, go to this post...

and to see how I rebuilt the gearbox, you can turn to this one.