It's just wind
You can’t talk about motorcycle aerodynamics without mentioning Moto Guzzi’s wind tunnel. Contrary to popular belief Guzzi weren’t the first motorcycle factory to have a wind tunnel, but given that Aermacchi’s was built when they we still making aeroplanes we’ll let it pass. Moto Guzzi started work on the tunnel in 1950, and were using it by 1952. From then on development of the factory racers focused on aerodynamics, streamlining initially an enlarged rear mudguard, but soon