I had two Whizzers when i was a youngster in the 1950's. One like in the picture - they were built on a Schwinn paper-boy bike - and a smaller framed Whizzer "Sportsman". Even then. parts were no longer available and the engines broke a lot, worst case, throwing the con rod. The engines were actually designed and first built in the 1930's. Mine would bury the needle on its bike speedometer (it said 45 mph). The cops would love to catch kids back then on unlicensed motorized contraptions of any kind - crime of the century I guess. You could remove the drive belt and pedal it like a regular bike and put the belt back on when you got to a nice private road. Modern replica Whizzers were available a few years ago, but I guess they found people were not willing to pay the nearly $3,000 price they had to ask.