AMA Superbike Championship is an American motorcycle racing series based in the United States. The series is organized by MotoAmerica and is sanctioned by the American Motorcyclist Association (AMA) as well as the Fédération Internationale de Motocyclisme (FIM). For most of its existence it has been considered the premier motorcycle road racing series in the United States. The championship features “highly modified, production based liter class motorcycles” competing at premier tracks across the country.
The AMA Superbike Championship can trace its roots back to the AMA Open Production event that began in 1973. AMA Open Production was hosted alongside the AMA Road Race National at Laguna Seca Raceway in 1973 and 1974. By 1976, the event became a major class, appearing at all 4 AMA Grand Nationals that season, and its name was changed to Superbike Production. In 1986, the AMA made the Grand National Championship into a dirt-track-only series splitting off the road-racing rounds into their own series, the Superbike Production events became the AMA Superbike Championship. In 2015 MotoAmerica became the series organizer, resulting in all AMA Superbike Championship events being held under the MotoAmerica name.
History In the early 1970’s AMA road racing consisted of two classes of Grand Prix style road racing machines: Heavyweight and Lightweight. The Heavyweight class, akin to Formula 750 in Europe, limited displacement to 750cc; while the Lightweight class limited 2 stroke engine displacement to 250cc and 4 stroke displacement to 360cc. Required by homologation, these motorcycles “must be a standard catalogued production model and at least 200 of this same model with identical engines and transmissions must be available for inspection and/or purchase within the United States”. While they were based on a standard production model, these motorcycles were either purpose built, or highly modified for racing, equipped with high performance engines and aerodynamic bodywork. Commonly the teams racing in these classes were factory backed, and capable of bringing engineering and financial resources unavailable to the common person. By 1974 both the Heavyweight and Lightweight Classes were almost completely dominated by the Yamaha TZ, and fans were becoming tired of the watching the same make and model win two seasons in a row.
Open Production (1973 - 1975) The early 1970’s saw the introduction of many high performance, large displacement road bikes such as the BMW R90S, Kawasaki Z1, and the Ducati 750SS. These motorcycles brought unprecedented levels of performance and power to the showroom floor, needing little to no modification to make them competent racing motorcycles. Buyers of these bikes knew this, and were eager to begin competing in races aboard their performance oriented machines. Soon, various club racers were competing in grassroot production based race events across the country.
Sensing the growing desire for production based racing, AMA race promoters Gavin Trippe and Bruce Cox invited production racers to compete at the 1973 Laguna Seca AMA National Road Race Weekend. Two production based races occurred, one being the Open Production class and the other being the Lightweight Production class, which was limited to 350cc. The regulations for these races required the motorcycles to retain their stock appearance, exhaust, brakes, instruments and carburetors. Yvon Duhamel won the first Open Production race, riding a Kawasaki Z1 provided by U.S. Kawasaki factory team. The event proved to be popular with racers and fans alike. Spectators enjoyed watching racing between machines that were available to the public, while racers enjoyed the low barriers of entry for the same reasons.
Other Road Race Nationals began adding Production races to their lineup. In 1974, Open Production returned to Laguna Seca, drawing enough popularity for it to make the cover of Cycle News. Later that season, the Ontario road race national featured an Open Production event, this time won by Reg Pridmore on a BMW R90S. The AMA introduced its first official road racing category for production class motorcycles as a support class in 1975, which served as the precursor to the Superbike Championship. The 1975 season saw both the Daytona Bike Week and Laguna Seca feature Production racing with David Aldana and Yvon Duhamel winning each respectively riding Kawasaki Z1 motorcycles. Duhamel switched to a Kawasaki H2 motorcycle to win the Production Class at the 1975 Pocono National, marking the last time that a two-stroke motorcycle won an AMA production class race.
Superbike Production (1976 - 1982) By 1976, the popularity of production racing, particularly around the Open Production class had swelled sufficiently for the AMA to make Open Production an official championship class to be run at all Round of Road Race Nationals. The name Open Production was dropped in favor of Superbike Production. Rules mandated that motorcycles competing in Superbike Production must “retain stock chassis and original silhouette. The engine could be modified as long as it retained the stock stroke - capacity limit was increased to 1000cc - but it must run stock carbs and stock exhausts”.
At the inception of the series there was little competition between the more experienced teams racing European twin cylinder bikes, which included the BMW R90S, Ducati and Moto Guzzi motorcycles and the teams racing the more powerful Japanese inline fours from Kawasaki, Suzuki, and Honda. While the Japanese bikes produced more horsepower, the European bikes tended to have superior handling. "In the beginning, the liter bikes actually lapped slower than the AMA 250s". The power being produced by the modified Japanese four cylinders was easily overcoming the bike's flexible double cradle frames and stock brakes. Since the rules permitted engine modifications, but forbade chassis modification, teams fielding the Japanese four cylinders could do little to address these poor handling characteristics.
The inaugural series in 1976 consisted of four rounds, BMW took three wins and Moto Guzzi took one. The Championship was won by rider Reg Pridmore on a BMW R90S owned by Team Butler and Smith. For 1977 the series was expanded to 7 races and the European machines continued to show their strengths, winning the first four rounds. By the 5th round, after two seasons of work, the Team Racecrafters Kawasaki Z1 won the first race for a Japanese motorcycle. Racecrafters and Reg Pridmore - who changed teams mid season - went on to win the Championship. 1977 also brought the launch of both the Suzuki GS1000 and Kawasaki KZ1000 motorcycles. These bikes were able to take full advantage of the 1000cc displacement limit and resolved some of the handling issues of the earlier models. By 1978, Yoshimura Suzuki and Vetter Kawasaki were two of the leading teams taking advantage of the new 1000cc Japanese machines. The 1978 season also brought new rule changes to the series. More extensive modifications, such as aftermarket 4-1 exhausts were allowed. Fierce competition between Suzuki, Ducati, Kawasaki and BMW continued, with the Championship again going to Reg Pridmore, this time riding a Vetter Kawasaki KZ1000. Superbike Production saw more changes in 1979 for both the motorcycles and race format. Racing carburetors were now allowed, marking another step away from the production origins as teams sought to make their bikes more competitive. The Daytona round, previously a 50 mile race distance, was extended to 100 miles, and allowed a refueling pitstop. Yoshimura Suzuki, which had seen success in prior seasons, went on to win the 1979 Championship with rider Wes Cooley.
As the series gained more and more attention in America the factories took note. In 1980 Honda entered the series with a factory team and brought a top rider from their stable, Freddie Spencer, to compete on their behalf. The Kawasaki factory team, which began in 1979, hired Rob Muzzy, an experienced dirt track mechanic to build their engines, and eventually the entire bike. The engine displacement limit was increased to 1025cc, likely to accommodate the stock displacement of the Kawasaki KZ1000. Despite the best efforts of the Honda and Kawasaki factory teams, Yoshimura Suzuki and rider Wes Cooley continued their success and won the Championship in 1980. By 1981, the Kawasaki factory team had refined their KZ1000 and entered a period of success, winning the 1981 and 1982 Championships with rider Eddie Lawson.
The 750cc Era & The Homologation Specials (1983 - 2002) By 1982, the 1000cc four cylinder motorcycles were producing up to 150 horsepower. Despite some improvement over the early years, the power and speed of the bikes were still overwhelming their chassis, brakes and tires, generating real concern for rider safety. Thus for 1983, the AMA, working with the top teams, decided to reduce the displacement limit for four cylinder motorcycles down to 750cc. Two cylinder motorcycles were allowed to retain the 1000cc displacement limit.
Honda, which had been competing in the series with bored out versions of the CB 750, came prepared for this rule change with new technologically advanced motorcycle, designed to win the AMA Superbike Championship. This bike, the VF750F, was a large departure from the air-cooled, perimeter frame, twin shock motorcycles that had won in prior years. Its chassis featured a square tube steel perimeter frame which wrapped around the outside of the engine and monoshock rear suspension. It was powered by a liquid cooled V4 engine, with four valves per cylinder, dual overhead camshafts and a slipper clutch. Where the original Japanese 4 cylinder bikes became race machines from production origins, the VF750F was a bike specifically built for racing in mind, and marked the beginning of a period of great technological advancement.
Honda did not experience immediate success with the VF750F. The 1983 Championship began with Wayne Rainey winning the inaugural race on Team Muzzy Kawasaki GPz750. The GPz750 was regarded as a low tech machine at the time, itself based on the KZ750. Honda went on to win the next 5 races of the 14 race series that year. Despite this, the experience the Kawasaki team had from winning the Championships the previous two years, along with the talent of rider Wayne Rainey, allowed them to come back and secure a third consecutive Championship in 1983, defeating Honda’s VF750F.
As the popularity of the series grew the long established Daytona 200 motorcycle race, which had begun on a course constructed on the beach in 1935, and had moved to the asphalt auto-racing track in 1961, became a Superbike event in 1985. The event had been one of the few venues where FIM style Formula 1 500cc machines raced in the United States, but the speeds the machines were reaching on the high-banked tracks were deemed unsafe given the tire technology of the time. This increased the visibility of Superbikes even further, and cemented in the minds of many Americans that the Superbikes were now the de facto premier motorcycle racers in the United States.
In 1986, the AMA recognized the changing nature and increasing popularity of motorcycle road racing, and split the road racing series into their own championship. This made the Grand National Championship into a dirt-track-only series. The newly formed road racing championship consisted of only two classes; Formula 1 and Superbike.