Post Listing Update: This Bimota did not meet reserve with 18 bids up to $6,455.
The YB4 was Bimota’s fourth Yamaha-based bike, built around the FZ750 (2MG series). The machine was developed for the ’87 season of the prestigious Formula TT World Championship. It first premiered at the French Bol d’Or Endurance Race of ’86 but after homologation rules forced the company to churn out a minimum number of production road-goers, Bimota would use the Milan Motorcycle Show at the end of ’87 to introduce a road-going variant of the then-cutting-edge scoot. The following year, these machines would become available to the public, known as the YB4 EI (or Electronic Injection), whereas the non-street versions were called the YB4-R, or Race.
Powering the Bimota was one of Yamaha’s liquid-cooled 749cc four-stroke traverse four-cylinder, DOHC engines with Weber Marelli electronic fuel-injection (though the race models had Mikuni carbs) that reportedly made a cool 121hp at 10,500rpm and 65ft-lbs of torque at 10,400rpm. The YB4’s also used the Yamaha’s standard six-speed transmission in addition to the Japanese engine. But like all Bimotas, a big part of what makes the YB4 shine is its chassis, which was designed by Federico Martini. Instead of using Bimota’s traditional steel-tube structures, the fourth-Yamaha based bike from the boutique Italian manufacturer featured a frame comprised of two diagonal beams with internal ribbing, and the cylinders being supported via plates bolted to said beams. The entire chassis and swing-arm were both aluminum units which I believe was a first for Bimota’s trick frames.
The suspension on the YB4 was another key area the Italian super bike had a leg up on its Japanese donor machine. Up front, Marzocchi M1R forks with external adjustment for anti-dive absorbed the rider’s violent braking and the track’s imperfections while a single gas unit manages the aluminum swing-arm in back. The brakes on the ’88 Bimota consisted of dual 320mm discs up front and a single 230mm disc in the rear, with the entire system built by Brembo.
The YB4-R was capable of a standing quarter-mile in 10.8 seconds, hitting 125.4 mph in the process. In total, the bike reportedly weighed in at 396.8 lbs dry. Supposedly a little over 300 units were made – many of which were raced – so like the vast majority of earlier Bimotas, the YB4-R is a rare beast.
The engine really wasn’t all that special, though the machine’s superb chassis and suspension enabled it to perform magnificently, and as a result quite a few impressive feats would be perform aboard YB4’s. On July 8, 1990 during the German Super Bike championship at the famous Sachsenring, Peter Rubatto clocked a circuit record on a YB4 with an average speed of 112.59 mph, dethroning Giacomo Agostini’s record which had stood since 1968. And arguably more importantly, during the 1987 World Endurance Championship, Virginio Ferrari would be crowned champion (while riding his YB4), while also putting an end to race legend Joey Dunlop’s five-year win-streak in the process. Dunlop had been unstoppable on his Honda for the half-dozen or so seasons leading up to 1987, so it was a big deal when he was beaten, especially by a bike from a company with much more modest resources.
The YB4 did well in countless other races too, including the 1988 World TT F1 Superbike Championship. That year Fogarty would finish first on his Honda RC30, followed by (Joey) Dunlop who was on the same bike – though Steve Williams would take fourth place overall that season while competing aboard a 1988 Bimota YB4-R. That very bike, which was a Team Fowlers Yamaha UK racer, is now up for sale. This bike is still in its race trim and the owner does mention it sporting some cool original patina, though the sponsor decals on the bike don’t appear to be the same ones that were adorning it back in ’88; same sponsors, slightly different decals, at least in size if you look closely.
More important than the decals are the original carbs this bike has, one of the key differences between the R and EI specs. This YB4-R also boasts a magnesium sump. In addition to the bike, this sale includes a letter of verification by Dennis Trollope, a renowned moto-dealer in Bristol in the UK. This would be an amazing bike to collect and display, parade, race, you name it, you really can’t go wrong with this one. You can find this ex-Steve Williams 1988 Team Fowlers Yamaha UK Bimota YB4 R (VIN: YB4*000027) for sale out of Piano, Italy with the bidding up to $3,250 and the reserve not yet met