Ok, here goes...Honda NR750. A very rare bit of unobtainium produced as a tech item for very well to do bike enthusists...the very few examples produced (under 200 worldwide) commanded $60,000 or more. Key highlight of this motorcycle was it's engine, a liquid cooled, DOHC V4 with gear driven camshafts. But the real technological tour de force laid within its combustion chambers and cylinders....four OVAL pistons (draw two cicles next to each other and then connect them with lines top and bottom) and you'll have an idea how the pistons were shaped. TWO titanium connecting rods per piston were operated off an intricate machined steel crankshaft. Each cylinder head contained EIGHT valves with a narrow combined angle in a pentroof (hemispherical) combustion chamber designed to create rapid flame propogation through the fuel mixture, which was sprayed into the intake ports via Honda's PGM fuel injection system using TWO Denso injectors per cylinder. This engine grew out of Honda's groundbreaking 1980's NR500 Grandprix bike, which used this technology in an attempt to compete against the very fast 4 cyclinder two-strokes dominating the circuits of the day. If you haven't figured it out yet, looking at the engine design and configuration, you'll discover that this was a thinly disguised V8....Honda neatly sidestepped the FIM rules that stated 500cc GP engines could not have more than 4 cylinders. I hope this helps!