Analysis of information sources in references of the Wikipedia article "Borile" in English language version.
Umberto chose a smart way to get the powerful and lightweight engine he wanted for his thumper. Using the cylinder head, cylinder, piston and crankshaft from the GM speedway engine, he got around the problem of developing a totally new engine from scratch. If you are not familiar with the GM engine, do not worry. Unless you follow speedway racing closely, there is little chance that you might have heard about it. Italy's GM have been producing world championship winning engines for a few decades.
