My inspiration for this Overland J.A.P. comes from vintage automobiles, mostly sports cars and racers. It also comes from vintage motorcycles and the privateer racers from the 1930s to the 1950s. A large douse of inspiration comes from the small independent motorcycle builders and restorers currently working in small sheds and garages all over the world.
So for the idea of using a racing engine in a road registered motorcycle rather than tuning a generic production engine came from Bugatti, specifically a 1934 Type 57. I have read of the Type 57 being described as just a barely civilized Type 35 racer. Or put another way; all of what Bugatti learned in racing was used to make the Type 57 the highest quality race proven touring car ever offered to be used for high speed road work. So when I had the opportunity to snag a J.A.P. Over Head Valve 4B racing engine and run it on the street in a road cycle; that inspiration came from the Type 57.
Images from Bring a Trailer from a For Sale posting.