Here's a bike most motorcycle folks have never heard of, the Harley Davidson V4 Nova. Bob Horn brought this up in a comment yesterday and pointed to a pretty interesting page that tells the story of a motorcycle that might have been and I thought it deserved a story of its own.
At the time the Shovelhead's replacement was being designed (the engine that eventually became the Evolution V-Twin), another engine and motorcycle combination was in the works. The Nova project was to be a smaller displacement family of high tech water cooled engines in V-Twin, V4 and V6 configurations. The cylinder sizes of either 200cc or 250cc gave engine size options ranging from a 400cc V-Twin to a 1500cc V6, and lots of interchangeable parts. The heads were 2 valve overhead cam with the potential for 4 valves at a later time.
Although the project had advanced to where they had 30 engines and 12 running motorcycles, it was never produced, a casualty of the AMF years.
The article is fascinating and if you are interested in H-D technology it's worth reading the whole thing. Thanks for the pointer, Bob!
HD Nova Project link is dead