Yeah, it's not legal technically speaking. There are no people or very few renting bikes, so if you are on a tight budget you'd need to buy and sell. You can go with a MC tour company, but this is like having your wallet raped.

Personally I'd think about taking China off the list, mostly it's an unnaviagable industrialized hell-hole with the biggest retard drivers known to man. Maps are near usless as about a third of the roads are rebuilt every year becasue they let massively overloaded trucks smash them to pieces and the GPS is out of date or wrong. However with some stunning scenery, friendly villagers which are far off the western tourst trail stuffed between these places if you've already been to the rest of Asia then well maybe it's for you.

However really Taiwan is better, it's Chinese speaking and cultrally, probably has better food, great roads, legal paperwork and maybe more authentic (as in China they smashed down every nice building and smashed every cultural relic in the cultrual revolution), just limited in size. Also think about doing a tour of India if you haven't already. Such a spiritual place, although some terrible drivers too, but legal unlike China.

But if you're determined and an experienced rider PM me and I'll give you tips and make you aware of exactly what laws you're breaking and the possibile consquences. Please don't bother to PM me unles you have over a years riding in Asia and 10 years experience total.

Hope this helps,
Z