[ChR1s]

Or*, you can simply apply for title. If you're the original owner, you will need to provide the CO (otherwise a Bill of Sale) and pay sales tax (or provide proof thereof). If you no longer have the CO, you can get a copy from the OEM. Once you've received the title, take that to your insurance agent and have them do up an RMV-1 for you. Once registered, you'll need to get an inspection sticker on the plate. For that, you'll have to be creative.

* I myself have not followed this procedure but I personally know someone who just plated his brand new CRF250X this past month, and that's all he did. Me, I just bought a DOT-legit Husky instead.