Britbike forum Forums British Motorcycle specific Brands Bsa bulletin board M33 Gearbox Selector Mechanism

I'm working on a gearbox from an early 50's M33 which has seen much better days. Aside
from the usual stuff, this box has had many things replaced with handmade "craftwork",
and some parts are missing.

I've circled the items of my immediate concern in the image below:



While the steel guide bush (ref #20) is still in the gearbox shell, the spring (ref #21) and
detent plunger (ref #22) are missing. Further, the selector plate (ref #23) appears to have been
hand made ... it does not have any detail to engage the detent plunger.

I found a site which gives details of the spring and plunger, but nothing about the selector plate.

Can anyone please help ?

Many thanks !
.. Gregg

Gregg: I have looked into a similar BSA gearbox.

This is the plunger sticking out of the guide. (seems to be stuck at the moment and does not pop out)



This is the plate fipped over to show a very small indentation for the plunger to engage.



When I look at these early gearboxes I cannot imagine them actually working at all given all of the little bits in the gear changing mechanism!

Gordo

Thank you, Gordo for taking those photos ... exactly what I was looking for! Hard to believe that detent does much of anything useful.

I agree with you about the flaky shifting mechanism ... and the one I have here is worse than most because it was retired from the life of a work-a-day hack in Thailand. Then, it got dolled up and sold to a tourist ...

Everything I look at tells a story ... a sad story

Thanks again,
... Gregg