Bimota YB4E1-R Superbike
Engine: 749cc Yamaha liquid-cooled DOHC transverse inline four-cylinder, 68.3mm x 51.5mm bore and stroke, 12:1 compression ratio, 132hp @ 12,200rpm
Top speed:170mph (Hockenheim 1988)
Fueling: Electronic fuel injection and engine management system, with Magneti Marelli ECU, single injector per cylinder and four 42mm Weber throttle bodies
Transmission: 6-speed Yamaha close-ratio, chain final drive
Electrics: 12v, electronic ignition
Frame/wheelbase:Twin-spar aluminum frame/54.7in (1,390mm)
Suspension: 44mm Öhlins inverted telescopic fork front, Öhlins monoshock rear
Brakes: Dual 12.6in (320mm) Brembo floating steel discs front, single 9in (230mm) Brembo steel disc rear
Tires: 12/60 x 17in front, 18/67 x 17in rear
Weight: 363lb (165kg) with oil and water, no fuel
Thirty years ago, on April 3, 1988, the first-ever race in the World Superbike Championship was staged at Donington Park in England. It was won by Davide Tardozzi on the works Bimota YB4EI-R, marking the first step in what promised to be a march to the inaugural World title by the small, specialist Italian manufacture's 750cc 4-cylinder Yamaha-engined bike.
But after crashing in the second race held that day, Tardozzi forfeited any points on combined results for his victory in the day's first race — an anomaly in the rules that was immediately corrected, but not backdated, that eventually deprived him and Bimota of the World Superbike Championship (WSBK) title. After winning five races in the nine WSBK rounds held that year — two more than any other rider — Tardozzi went into the final race of the 1988 series in New Zealand leading on points, only to crash on the warm-up lap, handing the slower but more consistent Fred Merkel the first-ever World Superbike crown on his Rumi Honda RC30.
This wasn't just a personal tragedy for Tardozzi and Bimota, but seemingly even more unfair because it was the Yamaha-powered, fuel-injected YB4EI that effectively pointed the way for future generations of sport bikes from larger manufacturers, especially in Japan, to excel both on the racetrack and in the showroom.
Launched in fuel-injected street guise at the 1987 Milan Show, the YB4EI was the work of Federico Martini, and in carbureted guise in the hands of Virginio Ferrari had previously wrested the 1987 World TT F1 crown from Joey Dunlop and the Honda trophy cabinet. So Tardozzi's World Superbike challenge was recognition of the specialist Italian manufacturer's successful efforts to push back the frontiers of two-wheeled technology, then deliver the results to their customers on the street in the form of a racer-with-lights. For the lucky owners of the 317 YB4EI customer bikes made by Bimota from 1987 to 1989 — 19 of them the YB4EI-R competition version — the model set new standards in 4-cylinder handling and poise.
The Bimota YB4EI was the first series production 4-stroke motorcycle to use a GP-style aluminum twin-spar frame, which later would become almost universal on Japanese sport bikes. Bimota brought race track-derived chassis technology to the street, and was a leader in the adoption of fuel injection, employing it on the YB4EI and refining its Weber/Marelli engine management system to uncover EFl's benefits of better acceleration, reduced fuel consumption, a lighter and more responsive throttle action, and lower emissions — already by then an increasingly vital aspect of street R&D.
Order the May/June 2018 issue of Motorcycle Classics to read more about the Bimota YB4EI-R. Contact customer Service at (800) 880-7567 or contact us by email.
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