Something a lot of folks don't know is that a Harley Davidson motorcycle engine is just two cylinders of a radial engine. Same crank pin arangement etc. Thats what gives Harley that "Harley" (aircraft radial) sound.
I love radial engines, in fact theres a saying in the flying world that...."Real Airplanes Have Round Engines". Guess that could apply to Jet engines but was meant to refer to Radials.
Radial engines have something in common with the steam engine, and that is that they are a mature technology. Sadly as is always the case, just about the time we perfect something, somebody thinks thay have a better idea and kills off things that work near perfectly. This is why we have Jets now instead of those beautiful throaty Radials on our airplanes. Its also why we have noisy nasty diesel locomotives instead of steam engines too.
Thanks for the image, its a beautiful bike !
Scotty