The 57-year-old, from Glasgow, was travelling on the A932 road between Forfar and Arbroath at 16:20 on Saturday when the crash took place.
Officers investigating the incident said no other vehicle was thought to have been involved.
Investigations into the full circumstances are continuing, and officers have appealed for witnesses.
Police have named a motorcyclist who died in a crash near Forfar as Andrew Cassels.