Hi all ,

On my 1940 WM20, it missed the worm shaft and the brass fitting of speedo drive boxes, Thus, i bought a NOS drive box, but when I installed it, I realized that it was provided for the right-sided of the wheel (turns in the opposite direction that which I had).

Do you know what is the ratio (2: 1?) for the WM20 speedo drive box (frontwheel left side), for a classic S433M Smiths speedometer ?

thanks for your help

Marc,
France.

C11 and Bantams ( I think) run theirs on the left.

Hi Douglas,

Thanks for your answer about my wrong speedo box

But someone know what is the conform ratio for the WM20 speedo drive box, for a classic S433M Smiths speedometer ?

thanks

Marc
1940 BSA WM20

Hello Marc,
The ratio for the classic WD speedo is 2:1.

Noam.

email (option): noam10@gmail.com