Emergency services were called to the A59 Boroughbridge Road, near the junction with Plantation Drive, at about 5.30am today (Saturday).
The single-vehicle crash involved a silver-coloured Piaggio moped, travelling towards the ring road.
Police said the rider, a 48-year-old man from York, was pronounced dead at the scene.
Road closures were put in place following the crash, while officers conducted examinations at the scene.
Police have now appealed for anyone with information to come forward.
Anyone with information is asked to contact the North Yorkshire Police Major Collision Investigation Team on 101, quoting the reference number 12180168057.