DAYTON, Maine — A Lyman man died Saturday as a result of a motorcycle accident on Route 5, according to the Maine State Police.

Adam Kimball, 43, died as a result of head injuries suffered when he failed to negotiate a curve about 1 p.m. Saturday. Kimball’s motorcycle left the road and hit a tree.

He was not wearing a helmet, according to police.

Kimball was transported to Maine Medical Center in Portland and died later in the afternoon.

Excessive speed was believed to have been a factor in the accident.