when I used to commute down the Edgware Road, there was a chap who had hooked up a 2 stroke engine to a BSO and used to do about 30 down the bike lane each morning, with what looked like a length of copper piping as an exhaust and the rear sprocket bolted to the spokes of a regular wheel.
also the chap above builds a bike with an engine, then uses public transport to get about?!
Made me remind this
.