The 30-year-old man from Leeds was airlifted to Leeds General Infirmary following the incident on Wheldrake Lane at around 10.35am today where his bike and a black Mercedes had collided.
He was heading towards Wheldrake from Crockey Hill and the Mercedes was travelling in the opposite direction. The car driver, a 31-year-old man who lives locally in York, was uninjured.
The stretch of road was closed to traffic while police investigated and to allow the vehicles to be recovered. Highways were also drafted in to help clear debris and carry out repairs to the road. It re-opened at around 12.30pm.
Officers are appealing for people to come forward who witnessed the collision or anyone who recalls seeing the yellow motorcycle or the black Mercedes prior to the incident.
Call North Yorkshire Police on 101, select option 2, and ask for Dean Turner or Neale Rees. Please quote reference number 12180097997.