Have fun with NJ and titling a non-titled vehicle.
It's possible, and not all that hard, but you will spend the $500 (plus more) you spend on the actual bike to get it legal in NJ. Add to that if the bike ever did have a title (I'm guessing you are taking the current owners word) and its registered somewhere, or was stolen, or any of a million other possibilities.
I'd skip it.
You probably need to get it inspected at the specialized vehicle inspection station in AC.
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