I've said before that I believed there was a displacement limit for ATV's in NY state. Well, today, at Wheel-A-Way Motorsports in Fulton, NY I was corrected. The sales guy there (can't remember his name) filled me in on some details. The limit is for weight and not displacement. The weight limit is under that of most side x side's but well over any current ATV made, including dump truck's like mine. I wish I could remember the exact weight limit but I want to say it was around 900#.
Regardless, from this point on, take everything I say with a grain of salt!

This is right off of the NYS DMV site.
An all-terrain vehicle (ATV) is any self-propelled vehicle that is manufactured for use on off-highway trails. These vehicles are less than 70 inches wide and weigh less than 1,000 pounds.