A Lehigh County motorcyclist died in a one-vehicle crash on Sunday.

State police at Bethlehem and the county coroner's office identified the victim as John D. Watt, 32, of 6323 Hunsicker Road, New Tripoli. Coroner Scott Grim said Watt died of head injuries.Troopers said the crash occurred around 4 p.m. along the 6300 block of Hunsicker Road, near Route 309, in Heidelberg Township. Watt was operating a Kawasaki bike when he lost control while westbound. The bike left the road and struck a tree. Upon impact the fuel tank on the bike ruptured and led to a brush fire.Troopers noted Watt was not wearing a protective helmet.