Through the 1950s and most of the 1960s, four-stroke engines dominated all Grand Prix classes. Advances in two-stroke engine design began to demonstrate the technology's potential in smaller classes during the 1960s, and when the FIM introduced cylinder and gear restrictions in 1969, the departure of Honda, Suzuki, and Yamaha from the sport opened space for the development of competitive two-stroke 500cc machines.
Jack Findlay recorded the first 500cc class victory for a two-stroke machine in 1971, riding a Suzuki TR500. The result pointed toward the inevitable displacement of four-stroke technology at the top level.
A two-stroke engine fires on every rotation of the crankshaft, unlike a four-stroke which fires only every second rotation. For a given displacement, this gave two-stroke machines a fundamental power output advantage. The mid-1970s through 2001 saw the 500cc class permit both engine types at equal displacement, but without separate limits that would have equalised performance. The result was an environment in which all competitive machines were two-strokes, since the four-stroke's inherent disadvantage could not be overcome within the same 500cc limit.
Some two- and three-cylinder two-stroke 500s appeared during the era. They enjoyed a minimum-weight advantage under the rules and could achieve higher corner speeds, but generally lacked the outright power of the four-cylinder configurations that became standard.
Honda's attempt to revive the four-stroke in the premier class with the NR500, beginning in 1979, failed to produce competitive results. By 1983, Honda itself was winning with a two-stroke 500.
The era was marked by continuous and rapid development. The Suzuki RG500, introduced in 1974, pioneered the square-four cylinder layout in the 500cc class, and Suzuki's constructors' title that year was the first for a Japanese brand and the first for a two-stroke in the premier class.
Antonio Cobas developed a stronger and lighter aluminium twin-beam chassis in 1982 to replace the steel backbone frames that had been standard since the 1950s. By the 1990s, all major racing teams had adopted this chassis philosophy.
Honda's introduction of the NSR500 with a big-bang engine configuration in 1992 represented another landmark. The big-bang arrangement clustered the firing pulses together, delivering a more tractable power delivery that improved traction and allowed riders to exit corners more aggressively. In 1993, Shinichi Ito broke the 200 mph barrier during the German Grand Prix at Hockenheim riding a fuel-injected NSR500.
The two-stroke era produced a succession of dominant champions. Giacomo Agostini, who had won seven consecutive 500cc titles with MV Agusta, transitioned to Yamaha and won the premier class again in 1975. Kenny Roberts became the first American to claim the 500cc title in 1978, riding for Yamaha. Barry Sheene won for Suzuki in 1976 and 1977.
Freddie Spencer won both the 250cc and 500cc titles in the same season in 1985, a feat unmatched in the modern era. Eddie Lawson, Wayne Rainey, and Kevin Schwantz added American dominance to the 1980s and early 1990s, while Mick Doohan of Australia became the most dominant figure of the era's final phase, winning five consecutive 500cc championships from 1994 to 1998. His 1997 season, in which he won 12 of 15 races, represents one of the most dominant single seasons in premier-class history.
Àlex Crivillé became the first Spaniard to win the 500cc championship in 1999, and Kenny Roberts Jr. claimed the title in 2000, becoming the only son of a 500cc champion to also win the premier class. Valentino Rossi closed the era by winning the final 500cc two-stroke world championship in 2001, before going on to win the inaugural MotoGP title in 2002 on a four-stroke Honda.
In 2002, the FIM permitted manufacturers to enter either 500cc two-strokes or four-strokes of up to 990cc displacement. The much larger four-stroke engines proved decisively faster, and by 2003 no two-stroke machines remained in the MotoGP field. The 125cc and 250cc classes continued to use two-stroke engines until being replaced by the Moto3 and Moto2 four-stroke categories in 2012 and 2010 respectively. The last time a two-stroke machine was started in MotoGP was at the 2003 Czech Grand Prix. Valentino Rossi, who retired in 2021, was the last active MotoGP rider to have competed in the 500cc two-stroke class.