Are ATVs street legal in new york?

Nope, this is straight from the NY DMV website:

ON PUBLIC LAND

You may not operate an ATV on public land unless it is specifically designated for ATV use, and it is allowed by a posted sign.

ON PRIVATE LAND

To operate an ATV on private land, you must have permission of the land owner or lessee. If you receive permission, make sure you know the boundaries of the property, and respect any special restrictions or requests of the land owner. You could lose permission to ride on private land by littering, causing damage, or riding carelessly.