As a young teenager, before I studied engineering at MIT and before I was old enough to drive, I was already interested in design, fabrication, and motor vehicles. My first such project was a 3-wheeled go-kart that used a 3 horsepower engine from a pressure washer, a modified children’s tricycle, and a variety of hardware store finds. This simple vehicle was capable of speeds up to 55 km/hr (~35 miles/hr).
The other vehicle shown was a gas and pedal hybrid bicycle, with a small chainsaw motor attached to the front fork of the bicycle. It powered the front wheel of the bike through a two-stage chain and sprocket speed reduction.