The Suzuki RG500 XR34.
The Suzuki RG500 But again, Yamaha’s development was fast, and they then developed the OW models, which mated well with the aggressive, tire-sliding riding style of American dirt track prodigy Kenny Roberts. Roberts wheelied and slid his way to an incredible three World Championships in a row, blowing the world away with not only his speed and riding style, but demonstrating the potency of Yamaha’s machines, which by 1980 were twisting out an incredible 130hp.
Honda, meanwhile, stuck to its guns as a four-stroke company, which they had huge success with in the 125cc and 250cc classes in the 1960s. But as the rules throughout the 1970s kept both four-stroke and two-stroke displacement capped at 500cc, two-strokes had a clear advantage. Even at the height of the two-stroke era, Honda stuck to it’s guns, building the NR500. With unique oval pistons and 8 valves per cylinder, it was unquestionably the most sophisticated engine design in GP, but it remained at a disadvantage due to the huge power differences inherent in its four-stroke design.
Honda finally succumbed to the trend in 1982, finally building their own 500cc two-stroke. But the approach they took was dramatically different from the Yamaha and Suzuki who, locked in a power war, were building machines that were so powerful they became almost unmanageable, winning races almost as often as they launched their riders into spectacular crashes.
Honda’s project was led by a motocross engineer, who opted for light weight and maneuverability at the expense of outright power. The result was the now-legendary NS500, a light and slim race bike with a unique three-cylinder design in an L-configuration. Though less powerful than it’s rivals, the Honda was much more manageable, and Honda’s design philosophy was proven when Freddie Spencer took it to two World Championships.
Honda’s triple-cylinder architecture was unique, and made for a remarkably rideable bike (for being a 500cc two stroke anyway.) But at the end of the day, much of GP racing is still a power war, and it was still no match for the narrow, well-balanced, and massively powerful V4s that dominated the grid. Once Honda went full-bore into both two-strokes and the dominant V4 engine architecture, they became virtually unstoppable on the racetrack. By the late 1990s, Honda’s V4-powered bikes piloted by the brilliant Australian racer Mick Doohan won a remarkable 5 consecutive titles.
By the end of the 1990s, a full generation had passed since 500cc two-strokes stormed onto the tracks of Grand Prix – which became apparent when a second-generation GP racer, Kenny Roberts Jr., followed in his dad’s footsteps and won the world championship in 2000. Robert’s Jr. won it on a Suzuki, far advanced from the Suzuki that first proved 500cc two-strokes could even be race-worthy at all. By then, these vicious bikes were weighing well under 300 pounds and putting out 160-180hp – more than double the first generation of engines in the class, which were considered difficult to control even in their time.
But by the 2000s, two strokes had run their course. The motorcycle industry in general was turning away from two-strokes, as government regulations rendered them obsolete on the streets, and as manufacturers began to place more emphasis on four-stroke development that they could apply to their consumer models.
But before two-strokes sang their swan song in GP racing, the 500cc era would give motorcycle racing fans one more special gift – an up-and-coming young racer from Italy named Valentino Rossi. Riding for Honda, and under the tutelage of the legendary Mick Doohan, Rossi mastered the unruly two-stroke beasts, dominating the class for the last two years it remained. 2002 would see a rules change that allowed four-strokes nearly double the displacement at 990ccs, after which the two-strokes were placed at a disadvantage, quickly disappearing from the grid thereafter.
Rossi would go on to become a legend in MotoGP, with a staggering 7 more GP championships in the premier class alone. But Rossi always maintained a fondess for the wild, brutally powerful 500cc two-strokes that posed a constant challenge even to the most skilled racers in the world, a sentiment echoed by many of the racers who were around during that era of racing.
Even still, the 500cc two-strokes – with their otherworldy sound, distinct exhaust smell, and a hyper-aggressive nature unmatched by any of todays ultra-refined bikes – maintain a legendary status, and awe, charm, and thrill spectators and riders alike to this day. Click Here…