OK, my formal go rather than the previous thinking in public ...
I'm having a punt on Ferrari, about 150 or 160cc, very early 50's.
http://www.theworldofmotorcycles.com/vintagebike-images/ferrari_motorcycle_150cc_engine.jpeg
I just did a Google on it and a very interesting pipe design here and I cannot work it out why they would do something like this
Ferrari Motorcycles 1952 Ferrari 150 Sport