The big question is WHY?

If your intention is only to temporarily import the bike to the USA for the purposes of short-term tourism, I think it would be much, much less expensive for you to purchase a new 125-200cc motorbike in the USA, plate it there, then sell it when you leave. The cost of shipping a small motorcycle back and forth from Asia to the USA and back to Asia again will be far, far higher than the depreciation on a US purchase.

If you are thinking of buying a bike in Asia and permanently importing it to the USA (meaning, plating it there), forget about it. The bike you buy in Asia will not have met the safety standards mandated by the US FMVSS, even if it is identical in every respect to the same model that is sold in the USA. The problem is that it won't have a US Federal approval sticker on it for 1) Emissions Control, and 2) Safety standard compliance. That means you won't be able to plate it in the USA.

Trust me on this one, I have been there, done that, bought the T-shirt. I now own two identical Honda PanEuropean motorcycles - one in Europe with a European safety sticker on it (put there by Honda when it left their factory in Japan) and another one in Canada with a North American safety sticker on it (again, put there by Honda when it left their factory). Other than minor differences in the headlight and turn signals (differences that you really have to know where to look in order to find them), the two motorcycles are identical. But, neither one could ever be plated in the opposite jurisdiction, because they don't have the safety and emissions compliance stickers on them required by the opposite jurisdiction.

Michael