In April 1978, Honda wants to make a comeback to World GP. At that time, all of the bikes uses 2-stroke engine. Honda wants to use 4-stroke engine. So, how do they get maximum power to compete with the more powerful 2-stroker? Oval piston was the engineering piece that could answer the question. In theory, oval piston can create a V8-like engine with only 4 piston. So, V8 power in the form of V4. This technology gives me some insight of how Honda thinks to overcome a certain problems.
You must read the interesting original post by Honda here: http://world.honda.com/history/challenge/1979pistonengine/text/02.html