Chang Jiang is the name of motorcycles that were once manufactured by the China Nanchang Aircraft Manufacturing Company. It takes its name from the Chang Jiang River, also known as the Yangtze. The CJ750 motorcycle is based on the original 1956 Soviet IMZM-72 which itself was derived from the earlier German 1938 BMW R71. They are often erroneously referred to as BMW "replicas" when in fact, they are derivatives of the IMZ M-72.Production began in the late 1950s or early 1960s. They were originally produced for the Chinese military and are powered by an air-cooled, four-stroke, opposed flat-twin engine displacing 746cc. The rear wheel is shaft-driven.