My first Sirio (and maybe my last) was a R&B Xenon-R, just a normal engine made by Sirio.

An investigation by my sponsor (he has a metal company and is specialized in precise enginering) did learn the crankshaft was a lot softer than Novarossi crankshafts and they warned me for the crankpin. After 4 liters the crankpin was already 0.03mm smaller and I doubt it would reach 10 liters.
Did get a new conrod and the hole for the crankpin was to small. Did drill it up to the right size and it lasted 1 liter. This 2 problems I had with the engine beside the stories about bad bearings do tell me it is no quality.....

Now I have a JP Eagle and it goes like hell......