The 52-year-old is believed to have struck a deer while riding on the B4425 road near his home in Cirencester, Gloucestershire.
The crash is thought to have taken place around 7.50pm on Saturday evening.
Dealer released their first single Better Things To Do in 1983, at the height of popularity for the New Wave Of British Heavy Metal. Their debut album First Strike followed three years later and their most recent was 2010′s live offering The Final Concert, marking their reunion following a split in the 1980s.
In 2011 they embarked on their first-ever tour of Russia. Their most recent live appearance was at the Phoenix Festival in Cirencester in June.
The B4425 route is a favourite among local motorcyclists, who enjoy its good visibility and relative width for a minor road. However, incidents involving deer are a regular occurrence.