Firstly It would probably need to be EPA certified. Then there are things like turn signals which on some bikes are different in the USA, don't know why but they are .For instance does the Thai/EU CBR250 have the same turn signals. Speedo would have to show MPH.
If you have lots of time, don't care what you spend and want to give it a go, why not. At least do some surfing and find out what the exact requirements are.
Much less hassle to sell it here and buy a CBR250 when back the US . OR take it back, wait until it is 20-25 years old whatever the law is there, and then register it as a classic?