The CJ750 motorcycle is based on the original 1956 Soviet IMZ (Irbitski Mototsikletniy Zavod) M-72 which itself was derived from the earlier German 1938 BMW R71. Nearly all of them have sidecars. 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. (Different sources cite different dates.) 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.
The most common models are:
The M1 which has a sidevalve (flathead) engine and a 6V electrical system. This model is a clone of the M72 and closely resembles the 1938 BMW R71.
The M1M is also a sidevalve, however it uses a 12V electrical system and is equipped with a reverse gear. It also has an electric starter, where the M1 has only a kick-starter. These enhancements were designed with the help of German engineers.
The M1S (or "Super") uses an overhead-valve engine, 12V electrical system, electric starter and reverse gear. The OHV system is fundamentally of German BMW design.
All three models use the same frame and sheet metal. The M1 and M1M are nearly identical in appearance, but they can be distinguished by observing certain details.
CJ technological history includes racing bikes, experimental engines and futile attempts at modernizing the appearance of a long obsolete machine. Beginning in the mid-1980s, over a decade after the normalization of relations between China and the USA, China opened its markets to foreign motorcycle manufacturers, which expedited the end of CJ750 mass production. Today, the marque is kept alive by interest from foreign hobbyists.