A lot depends on the US side but to get the bike out of the country is is maybe interesting to read this https://motorcycleinth.com/dokuwiki/doku.php/export_clearance_procedures
As far as I am concerend you need a lot of different papers and documents. If you have never exported a bike before, I would ask a dealer or soem folks in the US about the risks and requirements. You know there's customs and costs that have to be taken into consideration.
Exporting to the USA is not a big deal - I have done it several times - email me - cmrichsw@yahoo.com
Check with a customs broker or the customs office in the USA to get the requirements of receiving a motorcycle from Thailand. There are many customs agents in the Yellow pages of the phone book you may have to interview several to find a good one. They have a fee but of you check into the USCS website you may find the answers there and will not need an agent. Ask the import duty fees normally about 20% depends on the US customs agent.
Ship by Sea with all paperwork -shipper will box the bike remove fuels,oils etc.
I can help you free if you buy the motorcycle from me - I am a used motorcycle dealer in Thailand contact me at cmrichsw@yahoo.com
any suggestions as to how i might go about doing this? the CZ-i meets US DOT and EPA requirements, so it's not a big deal, but i would like to know of reliable companies in thailand to deal with that i can purchase from