That reminds me of my first ride out on a motorised bike I'd made from a JAP engine mounted on my pushbike. I was enjoying the newfound freedom of powered vehicular travel on the open road (bridlepath) when I found myself stopped by a local copper. He was a little surprised to have found me doing this, as he was already in the middle of apprehending another teenager who was also testing out a motorised trike. He had an interesting day!
He let us both off with an attempted talking to. But this was how I met up with a like minded tinkerer and we went on to make all sorts of stuff together, from 2 and 4 wheeled vehicles, radio receivers, transmitters, aerials, rotators, linear amps, digital frequency meters, signal generators, machine tools, welders etc. I've lost touch with him now (this was about 40 years ago) but when we spoke about 10 years ago last he had 2 tanks, a helicopter and a lot more besides.
It all started with an electric go kart aged 10 (12V battery, with a dynamo for a motor), then I fitted one of my Qualcast / Suffolk engines to it and it just went from there. A couple of pics here. I like to say there is no law against (most of) it!
Murray