I have been dreaming of adding an engine to my mountain bike, perhaps mounting it on a sturdy trekking rack. The engines that are ready made for bikes do not have the horse power I desire. Fuji Engines has one that might work. It is designed for a large model aircraft engine. It is a 64cc gasoline engine, 5.7 horsepower and weighs about 3lbs. It cost almost $400.00. Does anyone know of a comperable engine for less money. Also, any practical suggestions on drive-train, so forth?