This is true:
Case In Point:
I personally found 2 KLR650's for two young visiting Kiwi's. (California)
They bought the two KLR's (cash) and registered them here (using a friend's address) and had them registered and legal in 30 minutes at DMV. Done. California DMV. We forwarded their title documents to them in Mexico. No problems. So they had titles in their name, which is required to cross borders world wide.

California DMV don't deal with immigration, visas or citizenship issues. You only need a local address. You don't have to be a citizen or prove residency. You don't need a local driving license and you don't have to present proof of insurance at time of registering .... but insurance IS required within in 10 days of registration.

The Kiwi kids never bought USA insurance as they were just 2 days ride from
Mexico. No problems at all since they were there within 10 days and they never got pulled anyway.

From Mexico they bought local insurance for each country. They rode all the way to Argentina. One guy sold his bike there, the other rode back to Peru' and sold his KLR there. They were on the road for about 10 months.

They spent about $3000 each for the used KLR 650's. They sold them for about $1500 each. So not bad for a 10 months trip. The bikes were BEAT by trips end. They fell off a lot and weren't real good at maintenance. But both survived and had a great time.

If me, I'd sell my NZ bike and use the money to buy something in USA. From S. America you can ship to EU, Africa or wherever ... or sell the bike off down there. (hundreds do just that here on HUBB ... look at classifieds over last year)

Or ... you could fly to S. America and buy a travelers bike. Getting it in your name may be a challenge but can be done.

Good luck