I talked to a guy a while ago who is a part-owner in a fuel filter factory here in Binzhou, Shandong province and originally from the US. According to him nearly all Chinese fuel is not/not properly filtered by the Chinese fuel companies. He recommends that all car or motorcycle owners should use imported Bosch, K&N etc fuel filters to ensure smooth running of their machines, whether fuel injected or running a carburetor, also that any gasoline based machine in China absolutely needs to be using an imported fuel filter. This idea is backed up, I believe, by Chinarider who with BMW Motorrad Germany have already found impurities in Chinese gasoline.

He also suggests that using most Chinese fuel filters would currently be useless as most Chinese manufacturers are unaware about the micron-sized gaps required that should be used in fuel filters to filter particles effectively. This situation will most likely change in a few years as his and other companies' filters develop and improve in effectiveness.