Chang Jiang (simplified Chinese: 长江; traditional Chinese: 長江; pinyin: Cháng Jiāng) is the transcribed brand 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 or, in English, the Long River.
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CJ750
The CJ750 motorcycle is based on the 1956 Soviet IMZ (Irbitski Mototsikletniy Zavod) M-72 which was derived from the 1938 BMW R71. Nearly all of them have sidecars.
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 side-valve (flat-head) 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 side-valve, 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. All of these enhancements were designed by the Chinese.
The M1S (or "Super") uses an overhead-valve engine, 12V electrical system, electric starter and reverse gear. The OHV system is of Chinese 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 in their electrical systems.
CJ technological history includes racing bikes, experimental engines and futile attempts at modernizing the appearance of a long obsolete machine. In the 1990s, 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.
History
Official records have been lost to war or kept state secrets so all we have are competing theories backed up by plausibility and scant proof. However what is known is life for this bike started as a 1938 BMW R71, from it's German beginnings to the Soviet Union and ultimately to China. There are three leading theories which use as the mechanism of R71 technology transfer: reverse engineering, espionage, and official licensing.
Theory #1: Soviets reverse engineer BMWs they buy through Sweden One theory has it that in 1940 the Soviets bought as many as five BMW R71s from neutral Sweden. These bikes were shipped to Russia where they were tested/evaluated and ultimately reverse engineered. Many (if not all) of the bikes were disassembled. Engineering blue prints/drawings and casting molds were made of all parts. Within two years the Soviets were producing the very nearly indistinguishable M-72.
Theory #2: Soviet spy steals blueprints and bikes from BMW Another theory has it that in 1940 a Soviet aircraft engineer named Serdjukow, an employee at BMW's Munich manufacturing plant from 1935 to 1940, was able to get a hold of R71 blue prints and send them (along with several bikes) to mother Russia. Within two years the Soviets were producing the very nearly indistinguishable M-72.
Theory #3: BMW sells the R71 and its tooling to the Soviets And finally, in this theory, BMW licenses the technology and sells the original BMW tooling to the Soviets in 1940 or early 1941, after production of the R71 is dropped in favor of the more aggressive and militarized R75 ("Elephant").
Early Production
During 1950, the Chinese "Peoples Liberation Army Beijing No.6 Automotive Works" had been attempting to develop a suitable military motorcycle by reverse engineering a German Zundapp KS 500 military motorcycle. The Chinese KS 500 based machines entered production in 1951, and in total 4,248 machines were built before responsibility for the manufacture of military motorcycles was transferred to Hongdu Machinery Plant and the Xingjiang Machine Plant. Both of these factories remain subsidiaries of the State-run aeronautic manufacturing industry even to this day. Chang Jiang 750 (Type I) The USSR's advances, largely based on their capture of the BMW R75 technology and tooling at the end of WWII gradually led them to the conclusion that the side-valve bikes were obsolete. As they began dropping their R71-based motorcycles in favor of the R75-based ones they began selling some of the R71-based sidevalves (M72) to China in the mid-1950s. Soon after the Russians and Chinese agreed to a deal by which China got the tooling the Russians were abandoning, so that the Chinese could produce their own R71 (M72) derived bikes. China wasted no time in dropping the KS 500 based machine for the tried and tested BMW R71/M72 design motorcycle. This new Chinese bike, based on the R71/M72 and now named the Chang Jiang 750, entered production on 30 November 1957 at state-owned Gan Jiang Machinery Factory (guo ying gan jiang ji xie chang). The early production was using a lot of Russian M72 parts such as fenders, frames, wheels, ignition keys, switches ,etc. Even some complete Russian-made M72s were relabeled as the Chang Jiang 750. Others had the Russian engine replaced with a Chinese made one. These early Chang Jiang 750s are so similar to the M72s that telling the difference can be difficult, though not impossible. Among the differences, Russian engine casings are smoother than Chinese ones. There are also differences in the bike’s frames, sidecar’s frames, and in the front fenders. More specifically, the fender on the Chinese bikes are two-piece attached together with bolts and screws where the Russian made are one piece attached by rivets.
The drivetrain on the Chang Jiang has been revised several times since production began. From 1957 until 1966 Chang Jiangs were fitted with a Type I engine and transmission. This drivetrain was almost identical to the German R71 and the Russian M72.
Chang Jiang 750 (M1: Type II) In September 1966 Chang Jiang began production of the Type II engine and gear box, but it was not until 1972 when the Type II engine replaced the Type I in general use. This continued use of the Type I engine in new 1966-1972 bikes was a result of a large surplus of Type I parts and engines. With so many Type I engines in use, parts for it were still in production until the early seventies. As time went on the military would service any Type I bikes and replace engines and/or gearboxes with Type II versions for ease of maintenance, parts availability, and improved engine characteristics. Many bikes with Type I engines had their original gear box replaced with Type II gear boxes. The most noticeable visible difference between the Type I and Type II engine is the location of its dipstick; the Type I engine has the dipstick at the bottom of the engine. All engines manufactured with a serial number of 661802 and higher are Type II.
At some point in the 1960s, the factory name changed to state-owned Chang Jiang Machinery Factory (Chinese name guo ying chang jiang ji xie chang), formerly guo ying gan jiang ji xie chang. In 1969, the Chang Jiang 750 underwent some minor design changes, primarily related to the sidecar frames and headlight-mounted switches. Gas tanks with tool boxes built-in (similar to those of the R71 and R75) also began to enter production around this time. No Chang Jiang 750 motorcycles had a Chinese built in tool box gas tank before 1970.
Birth of the M1M and M1S At the end of the 1970s the factory was once again merged into the airplane manufacturer GUO YING HONG DU JI XIE CHANG (Anyone know the English name?). Also in the late 1970s the Chinese started production of a 6v over head valve (OHV) 30 horse power engine. Only a few of these original engines are to be found today, being quickly replaced in 1980 by a 12v OHV, 30 horse power engine. In December 1980, a small quantity of an engine called the Chang Jiang 900 was produced. This 900 cc OHV engine was an answer to the acquisition by the armed police of BMW motorcycles. Only a few of these bikes/engines were produced (probably no more than 10). Of those produced, only three engines have been found.
Modern production
In the mid-1980s the Chinese realized the original R71 side valve engine were somewhat less than state-of-the-art and began to work on upgrading their engine design. The result was OHV engine technology, of Russian origin. It is not known whether or not this technology was purchased from Russia or perhaps was the result of Chinese reverse engineering. Whatever the case it did not take long before a OHV 750cc-boxer engine, remarkably similar in design to the BMW /2 engine, entered production at the Ministry of Aviation and Space Nan Fang Engine Factory in Zhu Zhou Hu Nan province (Chinese name hang kong hang tian gong ye bu nan fang dong li ji xie gong si). In 1986, having seen benefits in the 12v electrics and some of the other improvements brought out with the OHV, the Chinese revised their sidevalve flathead models and now produced sidevalve/flatheads with 12 volts and a gear box with reverse.
The Chang Jiang brand is also found on single cylinder (two and four stroke) motorcycles and scooters, similar to Vespa and Honda. The CJ750 is no longer produced per se, but many have been restored from old military stock or assembled from parts. The CJ750 has become quite popular with enthusiasts outside China.
Purchasing & Importing
Most dealers outside of China are online with very limited if any actual stock of the bikes. Most bikes are ordered custom from the factories in China. While some people purchase through a dealer in their own country others may and do purchase directly from the factories themselves. Pro's and Con's need to be weighed by the purchaser.
Parts and accessories are readily available on such sites as ebay and directly through the many online dealers.
Importing into North America is done on a regular basis. Some areas of The United States are slightly more difficult to deal with there are no recent issues of anyone being disallowed the importation of a CJ. In Canada importing is quite simple as long as all documentation is in order.
As with any vehicle not common to a state or region, local rules and laws should be researched with care before purchasing and attempting to import.
Ownership and Maintenance
Overall the CJ750 is a very reliable motorcycle. Owners however should be able to at least minor repairs and maintenance on a fairly regular basis. It is quite common to have to adjust such items as timing, carburetors and minor electrical issues the day of unpacking the bike. These are not kit bikes, they come fully assembled, however quality control is not the same with major manufacturers. While there are mechanic shops with the experience of repairing older vintage style engines not all are able to. Generally it is more cost effective to learn how to repair these bikes yourself, as one might be doing the same repairs in the future. The technology is virtually the same as it was in 1938. Basic mechanic's tools are all that's required to do most if not all repairs. The average CJ owner, if they are not familiar with motorcycle maintenance and basic mechanic's, usually learn fairly fast. Online help in the forums are of great help as the regulars are always ready and willing to help those in need. This is all a part of "The Chang Jiang Experience"
External links
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Wikimedia Commons has media related to: Chang-Jiang motorcycles |
- The Chang Jiang rider forumThe place to discuss all things Chang Jiang
- Chang Jiang Unlimited A web site dedicated to Chang Jiang 750 motorcycles
- History of the Motorcycle and its various models - Chang Jiang Collective
- Comprehensive Service and Assembly Manual - Chang Jiang Collective
- The CJ toolbox User submitted tech tips and how to's
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