There were a few Imp engine bikes, the Imp engine was very tuneable and used in a number of racing cars in its heyday - the Ginetta G15 and the Davrian spring to mind. From what I recall the Imp engined bikes were a bit of a mess, it wasn't an engine that was designed to be on display. One of them turned up at Snetterton in the late 80s but if I remember it failed scrutineering and never got onto the track.
