This was a huge effort to really use aerodynamics on motorcycles in the 1950's.
In 1958, FIM banned the dustbin fairing, because it was dangerous with a crosswind.
^(check it on wikipedia)^
Basically the fairing acted as sail over the front wheel, so when a heavy crosswind
hit the fairing .....game over. Not to mention all the cooling problems this had on air cooled motors. These are some scans from this awesome book i got a couple months ago,
"100 Years of Motorcycles: A Century of History and Development"
by: Massimo Clarke (1986)
Moto Guzzi 8V, 1957
(top) Norton 500cc single, 1954
(bottom) MV Agusta 500cc, 1956
Moto Guzzi 350cc single