From the NYSDMV website herself:
A MOTORCYCLE MUST HAVE ALL OF THE FOLLOWING EQUIPMENT IN GOOD WORKING ORDER:
Approved lights, including headlight, taillight, stop lamp and license plate lamp, at least one red reflector on the rear and directional signals if the motorcycle was originally equipped with directionals or is a 1985 or newer model.
Brakes, on 1971 and newer motorcycles brakes are required on both wheels.
A horn or other warning device.
At least one rearview mirror mounted on a handle bar, although mirrors on both handlebars are strongly recommended.
A suitable muffler, “cutouts” or mufflers with removable baffles are prohibited.
Handlebars no more than 15 inches higher than the seat.
A seat for the operator and a passenger seat in the rear if a passenger is carried (no more than one passenger is permitted).