Honda had an oval piston V-4...............
that competed in bikes some 10-15 years ago, possibly longer. I don't remember now whether is was a four stoke or not, but for some time the four stokes could compete against two strokes with a "spot" on displacement, i.e. the four stroke could be larger displacement wise compared to the two stroke because of a power stroke every revolution versus one every other revolution with a 4 stoke. I don't remember now whether this was the F-1 class of bike racing or the next class down, but the engine was definitely an oval bore of about 500CC or larger displacement.
It competed for several years and then faded away, for some type technical problem.
ADD: Try Googling "Honda GP Bike History" and then use the search function for NS500. Two connecting rods for each piston, 8 valves per cylinder, 155HP @15,000RPM Four Stoke Year 1987. This will give you info on both 2 and 4 stroke bikes that Honda built to compete in GP 500CC which was the ultimate in engine and bike development for all the manufacturers that competed.
Each "piston" in the NS500 was oval in shape and filled what would be two round cylinders put together to make one cylinder oval in shape. A 750CC version was also made.