To challenge the 1983 season, Yamaha brought out the YZR 500(OW70). Starting with a two-cycle, water-cooled, four-cylinder engine, the YZR500 was equipped with an abundance of innovative mechanics. Its four cylinders were divided into an upper and lower group consisting of two cylinders each. Crankshafts were attached to each group, giving a unique V-shaped layout. With the upper group positioned at a 40 degree angle and the lower group set almost horizontally, it boasts a low center of gravity. The compactness of the engine was further enhanced by the neat placement of the carburetor between the two groups of cylinders. The engine was equipped with Yamaha's exclusive power valve system (YPVS) and puts out over 140hp. Parting from the widely used double-cradle style, Yamaha broke new ground in aluminum frame design and paved the way for the later Deltabox frame. The asymmetrical shape of the frame connects the pivot points of the steering head and the rear swing arm to make for a sturdy yet lightweight understructure. Tadahiko Taira and Keiji Kinoshita, both riding YZR motorcycles, challenged the All Japan Road Race and gave Japan a glimpse of their speed. Taira proceeded to take the 1983 Series Title and successfully defend it over the next two years. The pride and joy of Japanese motorcycle racing, Taira later went on the challenge the best in the World Grand Prix Championships.