Four-stroke straight-three motorcycle engines have been produced for both road and racing purposes by Aprilia, Laverda, The Motorcycle Book, Alan Seeley.
Four-stroke straight-three motorcycle engines have been produced for both road and racing purposes by Aprilia, Laverda, 365 Motorcycles You Must Ride. MBI Publishing Company, 10 Jan 2011 The Motorcycle Book, Alan Seeley.