I've been in that shop quite a few times, and, though your mileage may vary, I've found them to be contemptuous in the extreme of China's motor vehicle code and of their own customers. They openly and actively assert that 1) foreigners cannot register a motorcycle in their own name in China (but it's no problem because we can get you some non-Shanghai waidi plates), and 2) that riding with non-Shanghai waidi plates is "no problem" for foreigners. Their business seems to be built almost 100% on the gullibility of foreigners who are (sorry CJ fans) lusting after the nostalgia and alleged "cool" of a crappy, failure-prone, jury-rigged and commercially unsupported antique motorcycle.

I'd give wide berth to the Chang Jiang sidecars shop on Hami Lu.

cheers