I know that to have the wire loose is to make an effective antenna
Carbon core wire helped
Maybe a resistor spark plug?
When pedaling the reading is constant
When starting the engine reading can be coherent or sometimes shoot to 99 kph...
I will secure the wire to the fork and try it
If it doesn't work I'll use stereo microphone cable (2 conductors + shield)...
This motorized bicycle thing is better (and cheaper) than therapy