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.
Davide Tardozzi (2) at Oran Park in 1988 
Stephane Mertens (6) and Davide Tardozzi (2)
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.
The YB4 featured an aluminium twin beam frame and swingarm 
Fuel injection was also found on the road going version
Tardozzi narrowly lost the inaugural 1988 WSB Championship after a crash in the last round in New Zealand, eventually placing third in the championship.
Davide Tardozzi (2) narrowly lost the 1988 WSB championship after a crash in New Zealand 
Davide Tardozzi (2)
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!
Bimota claimed they produced over 300 of the YB4 for homologation 
Bimota YB4 
Bimota YB4 
Bimota YB4
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.
Bimota YB4 
Bimota YB4 
Bimota YB4
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).
Stephane Mertens (6) and Davide Tardozzi (2) 
Stephane Mertens (6) 
Davide Tardozzi (2) 
Bimota YB4 
Bimota YB4 
Bimota YB4
Source: MCNews.com.au