Information: - Kenneth Leroy Roberts (born December 31, 1951 in Modesto, California) 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. - A motor vehicle is a self-propelled road vehicle and off-road vehicle, commonly wheeled, that does not operate on rails, such as trains or trams and used for commercial purposes on the highways in the transportation of passengers, or passengers and property. - A motorcycle (also called a motorbike, bike, or cycle) is a two- or three-wheeled motor vehicle. Motorcycle design varies greatly to suit a range of different purposes: long distance travel, commuting, cruising, sport including racing, and off-road riding. Motorcycling is riding a motorcycle and related social activity such as joining a motorcycle club and attending motorcycle rallies. - Kelvin '' Kel '' Carruthers ( born 3 January 1938 ) is an Australian former world champion Grand Prix motorcycle road racer . He went on to become a successful race team manager , particularly in the US and Europe with Kenny Roberts . Carruthers , as the son of a motorcycle shop owner , learned how to work on bikes from a young age , started riding at 10 , and entered his first race at 12 . By the early 1960s he had won the Australian 125 cc , 250 cc , 350 cc and 500 cc National Championships . In early 1966 , he moved to Europe with his family to compete in British and International short - circuit races , including Grand Prix World Championship series riding a Drixton Aermacchi , and for early 1969 season riding bikes for the Aermacchi factory . Halfway through the 1969 season , he was offered a ride with the Benelli factory and won the Isle of Man 250 cc TT race . After the Isle of Man TT , Aermacchi released him from their contract to continue as a factory rider with Benelli and , he went on to win the 1969 FIM 250cc road racing world championship after a tight points battle with Santiago Herrero and Kent Andersson . After the 1970 Grand Prix season , he accepted an offer from Yamaha to race in America . Yamaha asked him to tutor a young American dirt track racer named Kenny Roberts . In 1973 , Carruthers became the manager of Yamaha 's American racing team . Under Carruther 's guidance , Roberts would win the 1973 and 1974 Grand National Championship for Yamaha . When it became apparent that Yamaha did n't have a bike able to compete with the dominant Harley Davidson dirt track team , they decided to send Carruthers and Roberts to Europe to compete in the road racing world championships . With Carruthers tuning the bikes and offering guidance , Roberts went on to win three consecutive world championships . Carruthers also managed Eddie Lawson to a 500cc World Championship . Carruthers went on to work for several Grand Prix teams through to the 1995 season . In 1996 , he took a job with the Sea - Doo... What is the relationship between 'kel carruthers' and 'motorcycle racer'?
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