Bimota YB6 EXUP

 

 

 

Make Model

Bimota YB6 EXUP

Year

1989 - 1990
Production 114 units

Engine

Four stroke, transverse four cylinder, DOHC, 5 valves per cylinder.

Capacity

1002 cc / 61.1 cub. in.
Bore x Stroke 75.5 x 56 mm
Compression Ratio 12.0:1
Cooling System Liquid cooled

Induction

4X 38mm Mikuni carbs

Ignition  

Digital  
Starting Electric

Max Power

145 hp @ 10500 rpm

Max Power Rear Tyre

127.3 hp @ 10600 rpm

Max Torque

94.1 Nm / 9.6 kg-m / 69.4 lb/ft.@ 9000 rpm

Transmission

5 Speed

Final Drive

Chain
Frame Two diagonal beams in section bar made of aluminium with internal ribbing. The cylinders are supported by plates bolted to the beams and the swing arm is made of aluminium

Front Suspension

42mm Marzocchi forks, anti dive system in the left tube of the fork leg and a hydraulic brake in the right. compression and rebound damping adjustable.  adjustable by four positions

Rear Suspension

Marzocchi single shock, compression and rebound damping adjustable. 

Front Brakes

2x 320mm discs 4 piston calipers

Rear Brakes

Single 230mm disc 2 piston caliper

Front Tyre

120/70 ZR17

Rear Tyre

180/55 ZR17

Dry Weight / Wet-Weight

185 kg  / 219 kg

Fuel Capacity

20 Litres / 5.3 US gal

Consumption  average

6.5 l/100km / 36.2 mpg

Braking 60 - 0 / 100 - 0

13.2 m / 36.0 m   43.3 ft / 118.1 ft.

Standing ¼ Mile  

10.8 sec / 201.8 km/h / 125.4 mph

Top Speed

269.0 km/h / 167.1 mph
The YB6 EXUP is a transitional model as it is really a YB8. It is distinguished only by the colouring. This may lead to confusion so it is easier to understand it you think of it as a special version of the YB6. It is interesting to note that this was the last bike designed and built by Ing. Martini as he resigned a week after its presentation.

The EXUP version of this 1002cc motor was chosen by Bimota to power their early 1990s YB6 machine, making it one of the Rimini factory's classic models. Matched to a twin spar alloy framed chassis, with huge Brembo brakes and sporty Marzocchi suspension, the Yamaha EXUP motor really had room to live and breathe, making this one of the fastest and best handling sports bikes of the Nineties. It was getting late by the time I reached Rimini gone nine o'clock and the sun had almost disappeared at the end of a long, hard day in the saddle. I'd been up at five, on the road before six aboard Bimota's fastest and finest. Now, many miles later, I was almost home.

The last hour had passed in a frantic, blindingly fast blur as the ferocious acceleration from the YB6's FZR1000 motor had shrunk the distance between hairpins, the eyeball-popping braking from its huge Brembo's had hauled its speed down yet again, and its handling and the grip of its massive Michelins had taken me round the tight, often badly-surfaced bends with an easy speed that had amazed me time after time. I was tired, and as the twisty road straightened and led into the town I was only minutes from the comfort of a cool shower and a hot meal at my hotel. I almost made it, but not quite. As I passed the sign for the city limits, something inside me made me stop, turn the YB6 slowly around and then, with a delicious sense of expectancy, power the bike back towards the hills one more time. The Bimota had to be returned to the factory the next morning, after all, and I wouldn't get many more chances like this. Riding a new Bimota is always a pretty memorable experience, and that's as true as ever of the YB6 although this FZR1000 - engined machine only just qualifies as a new model (despite the fact that in some countries it will be known at least for homologation purposes as the YB8).

The bike is essentially an updated version of the YB6, itself a 1000cc development of the similar-chassised, FZ750-powered YB4. In this latest guise the thick alloy beams hold Yamaha‚s current and considerably improved 1000cc straight-four motor, complete with the EXUP exhaust power-valve that gives it a healthy dose of much-needed midrange. The Bim's chassis stays almost unchanged, having little need of the multitude of mods that helped transform Yamaha's 1988 FZR Thou from also-ran to Top Dog. The original YB6‚s rectangular-section alloy spars retain that reassuringly chunky look; the b-for-Bimota monogrammed forks and remote-reservoir shock are Marzocchi's best (not always the ultimate accolade, it‚s true); the four-pot Brembo calipers bite on enormous, 320mm diameter floating-and-rattling discs; the white 17-inch wheels wear Michelin radials of predictably radical dimensions the rear a 180-section cover of even lower profile than before. And everywhere you look is the legendary Bimota quality of design and construction neat welding, smooth edges, perfectly-fitting parts that comes of sparing little expense, and of having only half a dozen carefully-trained assembly engineers, each of whom bolts together a complete bike individually from the ground up, and then signs for it. You can drink in the quality just from sitting on the YB6 and observing the intricately milled top yoke with the choke knob in its centre, the immaculately finished fairing with its low, swept-back screen... but I won't go on. You've heard it all before about Bimota's and it's all-true.

 The riding position is typical sport bike stuff, with highish pegs and a reach to low clip-ons from the rider's perch on the two-inch thick piece of foam that passes for a seat. Yamaha's excellent switchgear is complimented by good mirrors and a clean dash, the latter including a fuel reserve button that lights up, when activated, to remind you to stop for gas. The lipped screen works surprisingly well but it‚s a shame the shape of the Bimota's fairing means your hands get pressed into duty as lock-stops. The bike fires with a raspier sound than the Yamaha, the four-into-one pipe now capped with a smaller, less-restrictive silencer that I was told scrapes through noise tests‚ on the limit, and also doubtless prevents the scraping on the limit that the FZR's bulky stock pipe is prone to in right-handers (though only if you're completely mad). From the collector box forward the pipe is stock, retaining the EXUP hardware in its entirety. The EXUP works very well between 3000 and 8000rpm‚ said Bimota's chief engineer Pierluigi Marconi, who also pronounced himself most impressed with the

Yamaha's revised 20-valve combustion chamber design. I think the system will become increasingly important in the future. Bimota's silencer also has the benefit of producing an extra 4bhp of power at the top-end, which means that the YB6 smaller and 23kg lighter than the stock FZR is very possibly the Fastest Production Motorcycle in the world. Cut to the autostrada later that morning: your correspondent flat on the tank and flat-out in top as the Speedo needle crawled slowly past the 260kph mark, my eyes watered behind my visor, the zip on my leathers started coming undone as the wind shot down the back of my neck and every truck up ahead on the two-lane motorway threatened to pull out on me and end the experiment for good. Instead, I hit the brakes and pulled off the autostrada to speculate over a cappuccino. In the right conditions the 147bhp (claimed) Bimota would doubtless manage a genuine 270mph plus, but more impressive still is the Yam motor's awesomely smooth, torquey feel from just off the stop to the redline. If there was a glitch, a power band or a vibration patch I did not notice it I was always far too busy cracking the throttle open and then hanging on while the YB6 just rocketed away almost regardless of the revs. It goes without saying that the Bimota was rock-steady approaching its maximum velocity, but as with its engine it was at lower speeds that the chassis was most impressive.

The road right out of Rimini heads past Bimota's factory and soon becomes a riot of twisting, climbing tarmac whose surface varies between smooth and anything but. With the thick Marzocchi forks‚ compression damping on minimum and the shock on medium soft the Bimota gobbled it all up nonchalantly, passing on enough bumps through the thin seat to make my backside ache but never failing to keep the sticky Hi-Sport Michelins‚ vast footprints on the road. Steering is light though not as light as that of Honda's uniquely flickable RC30 racer-replica and neutral, stability impeccable, ground clearance absolute. And the brakes are equally brilliant; perhaps the only ones I've tried with a combination of bite and feel to rival the RC30's superb stoppers. I needed them, too, early the next morning, when a woman in a Jeep pulled out on me from nowhere while I was doing no more than 50kph in deserted downtown Rimini. I howled to a halt with perhaps 15mm to spare, and with a murmur of thanks to Signor Brembo on my lips. With its combination of smooth power, light weight and good brakes the YB6 is one of the world's safest bikes at least if you can resist the temptation to ride it fast all the time as well as one of the most expensive.

 The price is undoubtedly high but ultimate's never come cheap, and the Bimota not only matched my (initially slightly cynical) expectations but also exceeded them. As taut and as light even as the RC30 or Yamaha's new OW01 race bike-rival, the YB6 comes with 20bhp more power than any 750 plus the sort of midrange grunt that only extra cubes can provide. Fastest on top-end, fastest on the road back to Rimini, fastest anywhere. If the Bimota YB6 is not the quickest and simply the most exciting motorcycle I've ever ridden, then at least while that ride down from the hills is still fresh in my mind I'm not quite sure what is.