Electronic rev counter...

[A G Wood]

Hello
Has anyone found a solution to get a Tacho working on a magneto engine. I have tried one of the cheap inductive type with a wire looped around a plug lead but the display jumps around too much?
Thanks

I've never tried (maybe some one has?) but what about picking up the points open/close waveform from the primary circuit at the cut-out switch and using that to drive a tachometer-particularly one of the 1960's Smiths RVI/pulse types that don't physically connect to the primary circuit? Or does the intrinsic primary current reversal mess this idea up.