B40 Mk1 WD gear box upgrade

[DaveyP]

Hi all, I'm new here and just bought a 1969 b40 as above.
My question is:- where do get a gear cluster to to make the bike more road usable  ? The current gearing is very low.

P.s. when I say I'm new here, the last time I owned a bsa was 1976.....

[Greenfield]

You could start by changing the 17T gearbox sprocket for the standard 19T which is pretty straight forward.

[KernowPete]

Im going through the same with my c15 trials. I'm going up on the crank sprocket (new primary chain required) and the gearbox sprocket and down on the rear wheel sprocket to get a good speed range for green landing with road sections in between. It currently tops out at 30 mph. I'll keep the trials parts so it'll be easy to change back.

[cdsdorset]

Have a word with RTS racing.

[DaveyP]

Searching the Web, as you do, some one thinks a Starfire gearbox drops straight in, anyone here tried that  ?

[Rupert]

B24/44/50 "Victor" gearbox is a straight swap.
Another (hard to find) alternative is a C15G gearbox.
In each case you keep the B40 military top gear pinions and shafts and just swap 1st/2nd/3rd gear pinions.
Alternatively if you want some off road capability but no huge gap between 3rd and top you can fit C15G 3rd gear instead of the B40 military 3rd.
If you need gears I can probably help.
PM me if interested.
Rupert.