Does anyone know the gear ratio for the speedo drive that fits to the front wheel, as I need to purchase a new one. the old one would only come off in pieces and the last part needed a bearing puller to remove it. Also if anyone knows a good place to purchase one from that would also be of great help.
As far as I know, they are all 2-1 ratio and fairly specific to the girder fork BSA's from 1940. Most of the ones you pick up at jumbles are the wrong rotation. ie rear O/S wheel. The correct rotation is:- turn the driving dog clockwise and the cable drive needs to be turning clockwise also. I've found that post war Flying Flea's used them, but you have to drill the spindle hole bigger. Ron
Many thanks for the info. I think I will try to repair this one, the four small rivets have broken off so I may drill, tap and screw the internal retainer back in place with small BA screws the outer ring with the rubber ring is also deformed but should be able to tap it back into shape.
What appears to be rivets are actually the remains of screws...It is very easy to shear the heads off the screws if an attempt is made to undo them without first removing the peened over outer end of the screw by carefully filing them...
I've drilled and tapped them oversize previously...I think I used 6BA brass screws if memory serves..However, the nearest metric size (3mm)would be easier to obtain if you don't have the BA screws and taps..Ian
