The YB1 was the first motorcycle racing chassis kit produced by Bimota for sale to the public, being developed at roughly the same time as the HB1 for the street. Having gained some local notoriety from running his personal MV, and then Honda, on the racetrack, Massimo Tamburini was asked to build custom frames for private individuals who wanted to race them. He chose to work around the ubiquitous Yamaha TZ250 engine and initially tried both monocoque and open cradle designs before settling on the elegant double closed loop cradle design that you see here. This was one of two early chassis designs that Tamburini produced that used twin rear shocks (the other was the HDB2.) YB1 frames and kits – or Yamaha-Bimota kits as they were called at the time – were sold during 1974 and 1975.
The chassis were available for both the TZ250 and TZ350 engines, and there were a very few that were sold as complete "kits," featuring unique bodywork that fully enveloped the rider, including his hands, to produce a very aerodynamic front profile. The bodywork is very broad in the front and the tail section has an integral spoiler.
Bimota produced a sales brochure for these kits, and this is the first evidence that Bimota intended to enter into the motorcycle business (having previously been Tamburini's hobby working out of the Bimota Heating and Air Conditioning company.)
The YB1 had considerable racing success, most notably in the hands of Giuseppe Elementi (Kocis), Mario Lega and Roberto Gallina in the 350cc Grand Prix of 1974 (they garnered numerous podium finishes including a win by Lega at Misano), and then in 1975, Johnny Cecotto won the 350cc Grand Prix World Championship on his Bimota-framed Yamaha. Bimota did not receive much acclaim outside the paddock for this championship, because many racers during that era used custom chassis, and Cecotto was sponsored by Venemotos, the Venezuelan Yamaha importer, so Cecotto listed his motorcycle brand as a Yamaha – not a Bimota – but we all know! Cecotto had to beat many other top podium finishers on Bimota-framed racers, including Bruno Kneubuhler, Otello Buscherini and Mario Lega. Inside the paddock however, Bimota's successes were being noticed and requests for chassis and chassis kits started to grow. The success of the Yamaha-Bimota in 1975 led directly to Bimota's contract with Suzuki of Italy (Saaid) to produce a batch of 50 racing chassis for their water-cooled TR500 racing engine – which we now refer to as the beautiful Bimota SB1. The success of the SB1 project led Suzuki of Japan to commission 200 Superbike chassis for their GS 750 engine, whose revolutionary design later became known as the Bimota SB2. So, in effect, the YB1, with its success on the racetrack in 1974 and 1975, was largely responsible for the growth and development of Bimota into a proper motorcycle company.
The motorcycle featured here, from the Bimota Spirit Collection, is one of the complete kit bikes – chassis, fork, wheels, brakes and bodywork. It is completely original, unrestored as it left the racetrack many years ago. It features many of the custom motorcycle parts that Bimota had just begun to offer to the public, including the beautiful Tamburini-designed adjustable clip-on handlebars and "star design" magnesium wheels.