The end of the '80s and start of the '90s are remembered as one of the most dazzling periods in the history of the World Championship, and especially in the 500cc category, because of a number of extraordinary North American and Australian riders that left an enduring impact on the championship. It was a challenging time for racing in this category because it had become extremely demanding, with increasingly more powerful and intense motorcycles and very few riders who were able to handle them.
On top of that, the difference in performance between sponsored bikes and private riders' bikes make the latter lose interest in the 500cc category because it has become such an unattainable race. Little by little, people dropped out of racing until the grids were left bare. The resulting championship was disappointing and discredited, despite some of the most important riders in history leading the races.
Something needed to change before the 500cc category would become a victim of its own success. The president of the International Motorcycling Federation (FIM) called on manufacturers to find solutions to improve the bikes in the category and not only to change its teams. Yamaha offered up its second-level engine to chassis manufacturers and companies like ROC and Harris took up the offer.
Honda, however, worked secretly on a new type of engine because since it had won the 500cc title with Freddie Spencer in 1985, its NSR 500 seemed to be rooted in the past given a stability failure in the front suspension. Having a sturdy front end ended up being crucial to making the most of the driving technique with the back wheel: skidding. The solution wasn't in the cycle parts, the chassis, or the suspension but in the engine.
Honda's motor, equipped with a single crankshaft, which in technical terms is known as a true V4, was rugged and had an abrupt response. But Honda always wanted to keep this design to mark its identity and give it character. By 1988, Honda had developed a dual-crankshaft prototype with a different firing order, with all cylinders firing at the same time versus the traditional placement with the cylinders firing two at a time. The new configuration improved traction and made the bike easier to ride, but despite its efficiency, it was thrown out because it overworked the gearbox. Despite its shorter life span and more costly maintenance, the rugged single crankshaft engine was just more dependable.
In 1991, significant changes were made to regulations that opened the path to new opportunities. The minimum weight of 500cc bikes was raised by 15 kilos to 130 kilos. This extra weight went into reinforcing the most fragile parts of the bike. The gearbox was improved and strengthened, thus eliminating one of the disadvantages of the new firing order. That's when Honda decided to put its new concept into practice by retaining its single crankshaft engine but employing the new firing order. And like that, the Big Bang was born.
In 1992, the new Honda NSR 500 had an engine with a new crankshaft placement, with the four cylinders firing simultaneously at 70º. In this way, although the rear wheel takes on a heavy load with the four cylinders firing at once, there was 290º left to recover; whereas with the "traditional" firing order, firing two-by-two every 180º, the tire suffered less load but was systematically worn.
The best advantage to this new engine, with its distinguishable "popping" sound that gave it the name "Big Bang", was that the tires performed better in racing distances. Wayne Gardner seemed to adapt well to the new concept, whereas Mick Doohan was faster with the former engine, but he realized that the undoubted advantages of the new engine in terms of tire performance made it superior.
Initially, only three riders had the new engine: Gardner, Doohan, and the young amateur Alex Crivillé, although Garnder was injured in the inaugural test in Suzuka and again on his return in Mugello. So when he was finally in shape to race again, it was already the seventh race of the season in Hockenheim, and the weight of the team fell on Doohan. And he did not disappoint. He won outright the first four races of the season. The Honda Big Bang was superior, and it even turned out effective in novice Crivillé's hands, who in his third 500cc race in Shah Alam, finished on the podium, after Doohan and Rainey, with much more experienced riders finishing long after him. And in his eighth race, the day Doohan was injured, Crivillé won his first GP in 500cc.
Honda had achieved an engine that improved driving and made handling the wild Honda NSR 500 easy, which already at the time was at around 170 CV of power. The '92 season was marked by Doohan's serious accident in Holland, which left him out for the rest of the season, although he ended up reappearing in the last two races in an attempt to gain some traction, but it wasn't enough to keep the title from going to Wayne Rainey.
The other manufacturers quickly understood that they needed an engine like Honda's. By analyzing the harsh sound waves from the NSR's engine with an oscilloscope, they discovered the secret. Suzuki was the first to develop its Big Bang engine, which it presented at Hockenheim. Cagiva premiered it at the next race in Assen. And Yamaha a race later, in Hungaroring. The 1992 World Championship concluded with the four manufacturers applying the Big Bang concept to their engines.
The Big Bang had a democratizing effect on the 500cc World Championship. Until its appearance, the World Championship categories were clearly classed: there were riders with large-displacement bikes and riders with small-displacement bikes. But with the Big Bang, you no longer needed to have experience in skid control. Any rider from the lower categories could easily adapt to the 500cc without suffering terrible falls due to a loss of traction, violent highsides, the whiplash suffered by 500cc riders. They would still be spectacular and powerful motorcycles, but now they were easier to ride.