Is it odd he didn't make it to fit a Bugatti bike? Ettore's bike frame had four small-diameter downtubes (and 4 toptubes and 4 seat tubes for good measure), so the engine mount would have to be quite different.

Here's one reputed to be an original:


Crazed lunatic, er ah I mean gifted genius framebuilder Art Stump made a reproduction, or was it two? I forget, but here's a pic of one of Art's creations.

Made in the late '70s IIRC.

Mark B