I'm not giving up on finding this bike, but I suspect it was a very low volume producer. You never know, you may have the world's only surviving prototype.
Are there any casting marks on the engine, even if there's no other name but Rubino? The stylistic language of the bike is Italian/Spanish/Portuguese. Are the hubs, forks, any other parts that would have been bought from a supplier like anything else you have?
On the hubs are the name: ASTHON HC and BARUFFALDI MILANO
On the frontforkfrictionadjuster there's a name: TOMASELLI TORINO
And on the engine is stamped in 40x42 which is I think the bore x stroke
I bought the bike last winter in Italy
Well, that explains the style of it. It looks, as well, not later than 1952 to me. I have sent the word out on Facebook, we will see what the tide washes ashore.
Thank you both for your efforts and for sharing with the rest of us. I don't have a European bike and probably never will at this stage in my life, but I can see some of these that I sure would like to take for a ride. Vroom!
SB
[Nick Devonport] I've got Franck Méneret on the case. He reckons that the frame number could be under the pedal crank casting and would like to know what engine is fitted to it.