The 21-year-old rider was seriously hurt when his red motorbike collided with a silver Toyota Rav4 around 07:50 on Friday 2 February in St. Saviour.
Police want to speak to anyone who saw the crash at the junction of La Grande Route de St. Martin and Le Rue De Trot by Midland Stores.
Witnesses can contact police on 612612 or anonymously at Crimestoppers on 0800 555 111.
Lead photo taken from Google maps.