The 1957 Moto Guzzi 350 DOHC horizontal-single GP racer. Modern street motorcycles should be modeled after this elegant little bike -- aerodynamic, fuel efficient, and more than fast enough for highway use. This bike weighed 210 pounds and approached 140 mph. With lights and a passenger seat it would make great transportation and probably get 70 mpg in street tune. Motorcycles should get better gas mileage than cars or they can hardly be justified. It will eventually happen through law, because the costs of motorcycle accidents already outweigh the "benefits" of 180 mph toys that use 40% more gas than a SmartCar.