The 1978 Suzuki SP 370 was the first motorcycle with a single cylinder, four stroke engine, after the short lived Colleda CO and COX models from the fifties. In 1988 SP 370 was replaced by the SP 400, a similar bike but with more powerful engine.
SUZUKISP 370 1978 - 1979 Specs
Type:
Air-cooled, Single Cylinder, 4-stroke, SOHC, 2 Valves per cylinder