The Yamaha XS650 is a mid-size motorcycle made by Yamaha Motor Company. The standard model was introduced in October 1969,and produced through 1979. The "Special" cruiser model was introduced in 1978 and produced through 1985. The XS650 began with the 1955 Hosk SOHC 500 twin. After about 10 years of producing 500 twin, Hosk engineers designed a 650 cc twin. Later the Hosk company was acquired by Showa Corporation, and in 1960 Yamaha had bought Showa with Hosk's early design of 650 cc twin.

Kenneth Leroy Roberts is an American former professional motorcycle racer and racing team owner. In 1978, he became the first American to win a Grand Prix motorcycle racing world championship. He was also a two-time winner of the A.M.A. Grand National Championship. Roberts is one of only four riders in American Motorcyclist Association (AMA) racing history to win the AMA Grand Slam, representing Grand National wins at a mile, half-mile, short-track, TT Steeplechase and road race events.