1961 A50 blows main fuse when ignition turned on

[Allan G]

1961 would have been 6v from new not 12v, it should (if still original setup) have no zener diode, but it should have a three position ignition switch. ON:OFF:Emergency

Emergency is what you would switch it to if you have a flat battery.

Try turning the ignition switch in the other direction.

Appologies if you have converted the bike to 12v.

[limeyrob]

Good point, I'm really only familiar with the later A65 and just assumed 12V.