Appears to be based on a 1966 Honda CB 450 Black Bomber. Not all that pretty IMHO. Interesting valve springs, though.
Not beautiful - just plain bonkers.... http://www.douglas-self.com/MUSEUM/POWER/unusualICeng/toroidalIC/toroidalIC.htm
DIY 1000cc V-Twin 2 Stroke Project I stumbled across this some time ago. I think the machining on the crank cases is beautiful! Also a very very clever bit of home engineering! That mini v12 is incredible also
I get a lot of pleasure from seeing a finely engineered engine, I like to see compactness combined with elegance, typified by the 250cc Ducati single, the opposite of this as an example is the Royal Enfield engine, bits stuck on all over the shop, crude, heavy, low powered, it's only saving grace being it's ability to be torn apart by anyone with minimum tools I love mans ingenuity, and admire the simple but effective sterling engine, seen here made from a coke can. Soda can Stirling Engine - Homemade - YouTube
Triumph Trident T160 motor. Probably looks tougher than it actually was but what a beautiful looking bike.
I doubt aesthetics were part of the design brief (apart perhaps from the 6 cyl) but IMHO these Honda GP engines have a stark beauty of their own as a result.
I've always liked Vincents, but must take an awful lot of polishing - saw this one at Brooklands a few years ago.