Coil ignition capacitor size

you can fit an external one ,car type ,you will need to isolate the internal one if its faulty.. Or you could fit an electronic points assist unit (boyer) and then the cap is not needed. And you get better sparks.

Yep that is about it Robert. It is always best to fit the cap as near to possible to the points, ie on the side/rear of the dizzy. If you fit it right by the ignition coil then the piece of wire between the coil and the points becomes crucial. The actual mmf is about 2 but it is not crucial, what is, is the working voltage, I have measured 500v spikes on this line. I can fit a Boyer ignition to the 18D1 by the way.   AO(