For the CDI bike I have wired up a MSD 8918 Tach Signal Pickup and a Smart Fun Optocoupler which works grate.

I also have a bike with a Morris G5 magneto I would like a clean RPM from. I see "Auto Meter 9118 Tachometer Magneto Signal Converter" which I assume is a 12V out and I could run that into the Smart Fun Optocoupler.

Wondering if you could suggest a circuit DIY to pump the Magneto kill stud signal though that I could connect to the Smart Fun Optocoupler.