Bimota YB4 / YB4R

With Phil Aynsley

The YB4ei first debuted in YB4R form at the 1986 Bol d’or before contesting the 1987 World Championship Formula TT with great success – Virginio Ferrari winning with team-mate Davide Tardozzi finishing fourth in the eight-round series.

The YB4 was one of the first motorcycles to use an aluminium twin-beam frame. Designer Federico Martini also added an aluminium swingarm, and for the road version, fuel injection. The motor was from Yamaha’s FZ750.

Tardozzi narrowly lost the inaugural 1988 WSB Championship after a crash in the last round in New Zealand, eventually placing third in the championship.

303 YB4 machines were supposedly produced during 1988-89, plus a further 15 SP models. However it is very likely that the 303 number was inflated to meet WSB homologation. Bimota later claimed that 200 were destroyed in testing!

Output was 122 hp at 10,500 pm, while weight was 180 kg. This bike was originally exported to Japan before finding its way to Perth, then NZ.

The images of the factory YB4R were taken at Oran Park WSB round in 1988. The riders were Stephane Mertens (6) and Davide Tardozzi (2).