Giacomo Agostini
Fifteen world championships and 122 Grand Prix wins, neither total seriously threatened in fifty years. Agostini won eight 500cc titles, seven of them consecutively from 1966 to 1972, and seven 350cc crowns, frequently taking both on the same afternoon. His premier-class record reads 68 wins from around 120 starts, a strike rate above 55 percent that nobody in the modern era approaches, and he once won 20 consecutive premier races across 1968 and 1969, including a clean sweep of the 1968 season. The standard objection is machinery: MV Agusta's multi-cylinder fours were often the only genuinely competitive bikes on a thin grid. He answered it in 1975 by leaving MV for Yamaha and winning the 500cc title on a two-stroke at 33, the first two-stroke premier crown and the end of MV Agusta's seventeen-year run. He also won ten Isle of Man TTs before refusing to return after Gilberto Parlotti's death in 1972.