Honda RC160

The Honda RC160 is a 249 cc air-cooled DOHC inline-four racing motorcycle that Honda manufactured in 1959, the first four-cylinder machine Honda produced and the first Honda to use four valves per cylinder. Although it never raced outside Japan, its layout formed the basis of Honda's participation in the 250 cc world championship in the early 1960s. In 1954 Soichiro Honda decided that Honda's future growth depended on expanding abroad and that racing would be a way into European markets, so he set up a racing department with engineers Tadashi Kume and Kimio Shimmura. Honda also found large amounts of unburnt hydrocarbons in the exhaust, which led to combustion chamber changes and the four-valve head. At its debut at Mount Asama in the 1959 All-Japan Championship, RC160s took five of the top six places.