The 50cc homemade motorized bicycle spotlighted the other day looks pretty neat as a fun project but I found a company already producing something very similar. Derringer Cycles makes a Honda powered motorized bicycle in the classic board track style that has the same choice of power or pedal of the homemade version.
Brakes are drum up front, coaster in the rear. It holds 1.8 gallons of gas so the range under power is probably over a couple of hundred miles, plus with pedals, who knows?
The Derringer models look pretty well made and if this style of transportation appeals to you and you prefer not to build your own, you’re all set.
Link: Derringer Cycles