In a well-known Youtube channel there is a scene where a scooter had some kind of short circuit caused by magnetron used as a weapon from a distance. I never saw this channel to have fakes but one guy does not believe, saying:
OK, rough calculations erring on the side of the fake one. The real one shows a magnetron from a microwave oven, so let's say that's a really shitty one with 650W output. Let's assume you need the same amount of power to fry a bike's electronics as you do to light up a fluorescent tube. You would actually need a hell of a lot more, but we are being (very) generous and lazy when it comes to research.
In terms of distances, I'd say the tube video is about 1 metre and the bike one about 100 m. But let's be generous and lazy and call it 64 metres. For each doubling of distance, you need to increase the power by 4 to get the same field strength. So 2 metres would need 2,600 watts, 4 metres needs 10.4 Kw, 8 metres needs 41.6 Kw, 16 metres needs 166.4 Kw, 32 metres is 665.6 Kw and finally, the distance from the device to the bike, 64 metres would require a power supply that can generate 2.662 Megawatts of power. So, for a 9V battery that would require it to supply a current of almost 300,000 Amps. A decent PP3 can probably just about manage 1 Amp, maybe?