The accident happened on the A932 at a bend close to Fonah Farm outside Forfar at around 4.20pm. It is thought no other vehicles were involved.
Police say the 59-year-old rider died at the scene. Investigations continue, but police say the man was not local to the area.
The road was closed while crash investigators examined the scene and diversions were put in place just outside Forfar at the golf course turn-off to Auchterforfar and at the road leading to Brechin at the east end of Balgavies Loch.
A police spokesman said: “Tayside Division would appeal for anyone who may have information that could assist officers with their enquiries to contact Tayside Division on 101.
“As with all sudden deaths a report has been submitted to the procurator fiscal.”
