It happened at about 11:50 BST on Friday on the Dunover Road.
The police have appealed for witnesses.
Sgt Tom Stevenson said: "We are especially keen to speak to the driver of a small black vehicle, bearing L plates, that is believed to have been in the vicinity at the time and may have witnessed the crash."
A motorcyclist in his 70s has been critically injured in a crash in Ballywalter, County Down.