Hi Pete,

not sure about US - but to Germany you can declare it as part of your moving back. That is to protect your property.
For technical inspections and registration the bike does only need to meet the specifications of the country you are moving from and some safety critical items (e.g. hazzard switch).

This may or may not requiere that the bike is registered in your name or you have purchase contract stating that you own the bike for a certain period of time. Not sure about your residency status requiered and documents to prove it. I guess a residence permit in China should be sufficent.

That is a common way for German expats to get their Chang's back to Germany.
Maybe US has similar regulations.