Bum bike

Bum bike is any sort of bicycle that's been modified with a small internal combustion engine kit to act as crude but effective moped. They are usually unregulated in most areas. They are usually operated by a the homeless or a junky who doesn't have a car or motorcycle. This is done usually with a stolen bike and used as a means to get around town quickly while out commiting crime. They are usually very loud since they are use a two stroke motor. When one hears the sound of droning two cycle engine you know the junkies coming around to steal anything that's not nailed down.