#13 Manabu "Gaku" Kamada muscles the large, reluctant-to-turn Yoshimura Hayabusa around the track during the 1999 All-Japan Championship. He went on to win the S-NK class title. Photo courtesy of Yoshimura Archives.
1999-2000: Unleashing the Hayabusa's Power
In 1999, Yoshimura made a major decision. Rather than compete in the Superbike class, the team entered the S-NK (Super Naked) class in the All-Japan Road Race Championship and the Suzuka 8 Hours. Its base machine was the Suzuki GSX1300R Hayabusa.
Established in 1997, the S-NK class comprised two categories, both based on production motorcycles: NK1 for large naked bikes with steel frames and four-cylinder engines of at least 750cc, and X-Formula for four-cylinder machines of at least 800cc, with overboring permitted up to 1,350cc. If a machine finished in the top six, another entrant could purchase it at a fixed price: 3.5 million yen for an NK1 bike and 2 million yen for an X-Formula bike.
The S-NK class was included in both the All-Japan series and the Suzuka 8 Hours. In 1998, S-NK machines raced alongside Superbikes, and All-Japan points were awarded according to overall finishing order. Beginning in 1999, S-NK finishers received separate class points, with the number awarded determined by the size of the qualifying field. This meant that an All-Japan S-NK champion would be crowned. At the Suzuka 8 Hours, the S-NK awards were also presented separately from the overall results.
#13 Kamada approaches Turn 1 at Tsukuba during Round 8 of the All-Japan Championship on September 19, 1999. The S-NK and Superbike classes raced together. Behind Kamada are #55 Nukumi on a Sakurai Honda RC45 Superbike, #21 Shimizu on a Team Green Kawasaki ZX-7RR Superbike, and #99 Tsuruta on a Yellow Corn Kawasaki ZX-9R Superbike. Photo courtesy of Yoshimura Archives.
Although weight limits and other details of the Superbike rules differed slightly among the MFJ All-Japan Championship, AMA Superbike, and the FIM Superbike World Championship, their displacement limits were the same: 600-750cc for four-cylinder engines, 600-900cc for triples, and 750-1,000cc for twins. At 1,298cc, the Hayabusa exceeded the Superbike limit, but it was eligible for the X-Formula category in the All-Japan Championship and Suzuka 8 Hours. In the United States, it could compete in AMA Formula Xtreme or WERA's open-displacement Formula USA class. WERA, the Western Eastern Roadracers Association, was a nationwide organization with a stronger amateur focus than the AMA, but it held a substantial number of races on a significant scale.
Manabu Kamada, center, and Terry Rymer, left, celebrate on the podium. Yoshimura entered #13 Kamada and #43 Rymer in the MFJ Grand Prix at Motegi, the final round of the 1999 All-Japan Championship on November 7. They finished 1-2 in the S-NK class and 16th and 17th overall. Photo courtesy of Yoshimura Archives.
Fujio Yoshimura had initially planned to contest the 1999 All-Japan Superbike Championship with the GSX-R750. Then one motorcycle captured his imagination: the GSX1300R Hayabusa. Unveiled at Intermot in Germany in September 1998 and released the following year, the Hayabusa was billed as the "ultimate sportbike for the road." Its 1,298cc, water-cooled, DOHC 16-valve inline-four had an 81 x 63mm bore and stroke and produced 175ps. With a measured top speed exceeding 300km/h, this hypersport machine stood apart from the supersport models used as Superbike platforms and became the fastest and most powerful production motorcycle of its time.
A constructor's dream may be to race a machine developed freely in pursuit of an ideal. Yoshimura certainly felt that way. Imagine being able to modify every aspect of the engine, including its displacement, and build the chassis without restriction, with only safety and fuel capacity regulated. The 1970s AMA Superbike series had modification limits - engines could displace no more than 1,000cc, and the stock frame could only be reinforced - but it offered far more freedom than Superbike racing did in 1999. More importantly, Southern California was filled with tuners eager to modify motorcycles and build something extraordinary. That energy suited Yoshimura perfectly and inspired Fujio. It also resonated with enthusiasts, creating a culture of hot bikes fitted with 4-into-1 exhausts, high-lift cams, big-bore pistons, and racing carburetors.
Team Yoshimura Suzuki GP1 Daxim prepared for the 22nd Suzuka 8 Hours in 1999. Manabu Kamada, left, and Naoto Ogura, right, crouch in front of the Hayabusa, while Fujio sits astride the #12. The neighboring pit belonged to Moriwaki, which also entered the S-NK class with a Honda VTR1000F. The Yoshimura and Moriwaki families had joined forces for the midsummer Suzuka race since the inaugural event in 1978. Photo courtesy of Yoshimura Archives.
Did Yoshimura customers and racing fans really want to continue watching the team race the GSX-R750 when more powerful, larger-displacement, and more exciting motorcycles were available? Pursuing the premier All-Japan Superbike title was understandable, but Yoshimura believed something else mattered more. Fujio therefore chose the Hayabusa and entered X-Formula. Yoshimura raced the Hayabusa for two seasons, in 1999 and 2000.
As expected, the Hayabusa differed greatly from the supersport models normally used as Superbike platforms. It was large and heavy. Its 1,480mm wheelbase and 217kg dry weight helped provide stability above 300km/h, and it was relatively light for a hypersport motorcycle displacing more than 1,000cc. Building a race bike, however, was another matter. The 1999 GSX-R750, by comparison, had a 1,395mm wheelbase and weighed 178kg dry. The Hayabusa's available lean angle was adequate for the road but insufficient at racing speeds. Its long wheelbase also limited its willingness to turn, and its weight added another disadvantage.
The Yoshimura Hayabusa prepared for the 1999 Suzuka 8 Hours. Even in the S-NK class, it carried Yoshimura's traditional #12 and the equally traditional blue headlight. At this stage, the swingarm pivot was not adjustable. Photo courtesy of Yoshimura Archives.
For 1999, Yoshimura retained the stock main frame but fitted 46mm Öhlins front forks, an Öhlins TTX rear shock, a shorter Suzuki factory GSX-R750 swingarm, and a special suspension linkage. The forks increased rigidity, while the shorter swingarm and revised linkage improved traction and cornering.
X-Formula's freedom to modify the chassis was one of its special attractions. For the 2000 Hayabusa, Yoshimura sought better cornering and front-tire feel by cutting away the stock steering-head bearing section and welding in a machined billet component farther rearward. This placed more load on the front wheel and shortened the wheelbase. The team also opened up the left and right sides of the swingarm-pivot area and welded in billet components that allowed the pivot position to be adjusted vertically and fore-and-aft. Raising the rear ride height to gain lean angle had made the swingarm angle too steep; the adjustable pivot allowed Yoshimura to restore the proper geometry.
Another highlight of the 1999 Suzuka 8 Hours was Saturday's Special Stage, in which each rider started from a raised platform on pit lane. #12 Kamada received especially loud cheers, showing how much fans expected from the Yoshimura Hayabusa. Photo courtesy of Yoshimura Archives.
The already powerful engine was tuned from 175ps to more than 200ps. Modifications included high-compression forged pistons that raised compression from 11:1 to 12:1, high-lift camshafts, cylinder-head work, stronger connecting rods - stock in 1999 and Carrillo units in 2000 - a special crankshaft without the counterbalancer drive gear, a close-ratio transmission kit, and a lightened, drilled shift drum.
The 1999 electronic fuel-injection system retained the stock arrangement, with one injector in each intake port. For 2000, Yoshimura adopted a dual-injector system similar to that used on the GSX-R750 Superbike. Each cylinder had one injector in the intake port and a second in the air funnel upstream of the throttle plate. The upper injector operated only at high rpm, improving top-end power and acceleration.
To control the additional heat produced by the more powerful engine, the Hayabusa used two large stacked radiators that occupied most of the fairing's front opening, along with an air-cooled oil cooler originally designed for a Toyota Supra mounted behind them on the right. For 2000, Yoshimura added a water-cooled oil cooler at the upper left of the crankcase, combining a Yamaha YZF-R1 core with a machined-aluminum Yoshimura base.
The 1999 All-Japan S-NK field included Yellow Corn and BEET on Kawasaki ZX-9Rs and OVER deLIGHT on a Yamaha YZF-R1. Yoshimura named Manabu Kamada its lead rider. He won six of ten races and claimed the S-NK championship, while Naoto Ogura and Terry Rymer made one-off appearances for the team.
Although Ogura was not a full-time rider in the 1999 All-Japan series, he skillfully handled the bulky, heavy Hayabusa at the Suzuka 8 Hours. Photo courtesy of Yoshimura Archives.
Yoshimura paired Kamada with Ogura for the 1999 Suzuka 8 Hours. They qualified 15th with a 2:12.450 lap, 3.240 seconds off pole. The Hayabusa was exceptionally fast on the straights but could not match the Superbikes under braking or through the corners. The pair completed 199 laps, 14 behind the winner, to finish 16th overall and win the S-NK class as the highest-placed X-Formula entry. Moriwaki also entered the S-NK X-Formula category with a Honda VTR1000F, while Nojima's Kawasaki ZRX1100 attracted considerable attention in NK1.
Osamu Deguchi rides the #31 Yoshimura Hayabusa in the 2000 All-Japan Championship. He narrowly missed the title and finished 2nd in the standings. Photo courtesy of Yoshimura Archives.
The 2000 season began in tragedy when Naoto Ogura lost his life in an accident during preseason testing at Suzuka in March. The team was overwhelmed by grief, but the season would not wait. Yoshimura contested the All-Japan Championship with Osamu Deguchi, who finished 2nd in the S-NK class.
A Yoshimura mechanic pushes Deguchi's bike at a 2000 All-Japan Championship race. The large seat cowl improved aerodynamics and top speed, but it also made it easier for rivals to draft behind the bike. Photo courtesy of Yoshimura Archives.
For the 2000 Suzuka 8 Hours, Yoshimura paired Deguchi with Shawn Giles. They recorded a 2:11.245 in timed qualifying. In the Special Stage, where the top 20 qualifiers competed to set the first 20 grid positions, they posted a 2:11.329 to qualify 12th, 3.503 seconds off pole. They were, of course, the highest-placed S-NK entry.
The special S-NK podium in front of the pits at the 2000 Suzuka 8 Hours. From left are Osamu Deguchi, holding a portrait of Naoto Ogura, who had died in March; a jubilant Fujio; and Shawn Giles. The Yoshimura Hayabusa X-1R finished 6th overall and won the S-NK class. Photo courtesy of Yoshimura Archives.
In the final, Deguchi and Giles completed 209 laps to finish an impressive 6th overall and win the S-NK class. The winning machine set a new record of 215 laps. Rather than use the elevated second-floor stage reserved for the overall awards, organizers held the S-NK ceremony on a special podium in front of the ground-floor pits. Celebrating at eye level with the crowd suited the character of S-NK, and Fujio beamed as he joined the riders on the podium. Yoshimura had freely built the motorcycle it wanted to build, achieved the best possible result, and was rewarded by a wave of cheers from the fans. Overall victory went to the twin-cylinder, 1,000cc Honda VTR1000SPW Superbike, signaling the end of the four-cylinder 750cc era.
Beginning in 2000, Yoshimura called its Hayabusa racer the X-1R because Yoshimura Japan had released the limited-edition Yoshimura Hayabusa X-1, based on the Suzuki GSX1300R Hayabusa. Only 100 were offered, priced at 2.56 million yen. It was Yoshimura Japan's second street-legal complete custom motorcycle after the 1987 Tornado 1200 Bonneville, based on the oil-cooled GSX-R1100. More than a race-bike replica, the X-1 had the character and presence of a fully developed custom motorcycle. Its most striking features were the Yoshimura-designed fairing and 24-liter aluminum fuel tank, finished in the company's red-and-black colors. Dry weight fell from 215kg to 197kg, while ST-1 camshafts, forged high-compression pistons, cylinder-head porting and resurfacing, an injection controller, and a dual-outlet Tri-Oval Titanium Cyclone exhaust raised output from 175ps to 193ps. A close-ratio transmission supported more aggressive riding.
A prototype custom Hayabusa from Yoshimura R&D of America. Unlike the Yoshimura Hayabusa X-1's dual headlights, this machine uses one larger headlight offset to the left. The taillight also differs: the X-1 retains the stock Suzuki component, while the Yoshimura R&D Hayabusa has a built-in unit. Its silver 24-liter aluminum tank lacks the X-1's embossed Yoshimura logo. The exhaust is also a dual-outlet Tri-Oval Titanium Cyclone, but without the tapered tailpipe covers used on the X-1. Photo courtesy of Tomoya Ishibashi.
Yoshimura's success with the Hayabusa in the All-Japan Championship and Suzuka 8 Hours, together with the release of the X-1, generated an enormous response that reached the United States. Shortly after the X-1's launch, Yoshimura R&D of America unveiled its own Hayabusa-based street custom at Daytona Bike Week in March 2000. The fairing was a unique Yoshimura R&D design, and California Cycle Design added silver to the traditional red-and-black paint scheme. Superbike-spec Öhlins suspension front and rear upgraded the stock components retained by the standard X-1 prototype. Engine tuning largely followed the X-1 specification.
Rad Greaves' Hayabusa racer, which carried him to 6th in the 1999 AMA Formula Xtreme standings. As a Yoshimura R&D customer, he used an RS-3 titanium exhaust. Photo courtesy of Tomoya Ishibashi.
The Hayabusa also made its mark in the United States in 1999, when Yoshimura R&D customer Rad Greaves finished 6th in AMA Formula Xtreme, an open-displacement class for motorcycles of 745cc and above.
Two intense seasons with the Hayabusa passed quickly, and Yoshimura entered the era of its next weapon: the GSX-R1000.
Stories and photos supplied by Yoshimura Japan / Tomoya Ishibashi
Written by Tomoya Ishibashi
Edited by Bike Bros Magazines
Published on February 18, 2026