I do not know for certain, but here are some ideas:
the bike is registered in the U.S and has a title of NY state on my name.
i am not a U.S citizen nor a resident.
i have U.S driver license.
can it be shipped back to the U.S?
YES, BUT BECAUSE YOU WERE OVERSEAS, THERE IS A CHANCE THE EPA WILL DO A CHECK ON YOUR CATALYTIC CONVERTER (WHICH WAS KILLED IF YOU USED LEADED FUEL). MAYBE SOMEONE ELSE CAN HELP ANSWER THAT...
do i have to pay taxes?
NO -- IF THE BIKE IS TITLED IN NY, NO TAXES TO USE THE BIKE IN NY -- JUST HAVE TO RE-REGISTER
will i be able to re-register the bike since is not valid anymore (more than a year)?
SHOULD BE ABLE TO ON LINE AT http://www.nydmv.state.ny.us/
AND LOOK UP RENEWAL. IF NOT, YOU CAND DO IT IN A DAY AT THE D.M.V. WHEN YOU GET BACK TO NY. YOU WILL PROBABLY NEED TO USE A VALID ADDRESS -- A FRIEND WHO CAN FORWARD YOU YOUR MAIL, OR THE ADDRESS FROM YOUR NYS LICENSE
to do insurance again?
YOU WILL NEED IF YOU PLAN TO RIDE AROUND. YOU CAN GET ON-LINE FROM GEICO, UNIVERSAL, OR PROGRESSIVE. DO A SEARCH ON YAHOO FOR THESE COMPANIES
to sell it?
IF FAIR PRICE, WHY NOT? WHAT IS HARD IS TO SELL A NON-US BIKE TO SOMEONE IN THE USA.