Tim Moorhead, 50, crashed just before the Black Hut, on the Mountain section of the course on the Isle of Man, at around 8.05pm on Friday.
Married Mr Moorhead, from Whitstable, Kent, made his Manx Grand Prix debut in 2012, a statement from the Manx Motor Cycle Club said.
The statement said: "The Manx Motor Cycle Club wish to pass their deepest sympathy to Tim's family and friends. The coroner of inquests has been informed and an investigation into the circumstances of the accident is underway."
It is the second tragedy to hit the event in a week. On Tuesday, Stephen Mcllvenna, 39, from Randalstown, Northern Ireland, died in another qualifying session.
Mr Mcllvenna, from Randalstown, Northern Ireland, first competed in the grand prix in 2005 and won the Junior Manx Grand Prix in 2009. He also competed in the TT Races a year later.