Bimota SB6

The Suzuki GSXR 1100 engine was one of the classic hooligan powerplants of the early 1990’s, but it took an Italian Company called Bimota to realise its true potential as the scourge of all suburban neighbourhoods.

With 160mph performance, a short, wheelie-prone chassis and a screaming banshee wail from the underseat exhausts each time the rev needle passed 6,000rpm, the SB6 was perhaps the ultimate cafe racer special of the early 1990s. A stunning concoction of Japanese engine aggression, Latin style and sweet hi-speed handling.

A truly exotic, handbuilt, carbon fibre everywhere, R version of the SB6 was also produced for those who demanded the very best, which cost a staggering £17,995 back in the mid 1990s.

The carbon-fibre backed tacho was indicating 10,000rpm in top and the speedometer alongside had edged past 260km/h (approaching 165mph) when finally my nerves cried enough. Sitting up from behind the low tinted screen, I hit the brakes for the rapidly approaching right-hand bend, and the front tyre bit hard into the road as the bike shed speed even faster than it had been accelerating moments earlier.

Suzuki´s big engine coughed once, then again as I shifted my weight slightly in the seat and blipped the throttle to change down through the gearbox. Then, with a light touch on the clip-ons, I was banking into the curve, keeping towards the centre of the road to improve visibility on the way in, winding on the power gently half-way through, finally nailing the throttle to send the red, white and grey projectile screaming off once again.

My memory of the bike´s speed and stability on that stretch of tarmac remains vivid several days later, and no wonder. Such adrenalin-charged action is doubtless familiar to many GSX-R1100 riders, but this was something that the standard Suzuki could not have provided. For all the two machines´ shared powerplants, riding the Bimota SB6 confirms what simply examining the bikes and their spec sheets (and price tags) suggests: that there´s a world of difference between this exotic, lavishly equipped special and Suzuki´s mass-produced megabike.

In many ways the SB6 is long overdue. After all, despite the biggest GSX-R´s popularity, the 1100´s chassis has generally been far less impressive than its motor since the original model back in 1986. For most of that time Bimota have been building bikes powered by Yamaha´s rival FZR engines. Only now, though, have the Rimini firm produced a chassis for the 16-valve GSX-R.

There´s no sign of Tesi-type innovation here, but describing the SB6 chassis as conventional hardly does it justice. The frame is a twin-beam alloy construction, true. But the broad extruded spars that run diagonally out from the steering head curve and continue all the way down outside the engine (no conveniently angled-forward FZR cylinders here) to incorporate the swing-arm pivots. Bimota claim this design, which they call Straight Connection Technology, gives more rigidity than the familiar combination of extruded rails and cast alloy end sections.

Rear subframe design is even simpler: this bike doesn´t have one. In grand prix racebike fashion, the SB6 uses a self-supporting carbon-fibre seat unit. This blends smoothly into the petrol tank cover, which is made from an equally curvaceous composite of carbon and fibreglass, forming a seat-tank unit of unprecedented lightness and style.

Well, perhaps not unprecedented style. Bimota enthusiasts will recall that the firm´s first streetbike, the Suzuki GS750-powered SB2 of 1977, also featured a gorgeously sculpted full fairing and seat-tank unit. Like its modern descendent, the SB2 supported its rider without a rear subframe – though 17 years ago that feat required an aluminium-lined fibreglass tail section far heavier than this bike´s carbon construction.

The SB6 tailpiece is notable for more than just its strength and lack of weight. After leaving the engine, the Bimota´s four exhaust downpipes converge into two beneath the engine. These join to form a single pipe that rises vertically through a gap in the swing-arm, then runs back to two horizontal silencers in the seat-hump. With bodywork on, the only visible parts of the entire exhaust system are the silencer tips, which emerge above the rear light and carbon-fibre mudguard.

The swing-arm is a typically stout rectangular alloy unit, unusual in that its rising-rate rocker-arm is located on the right side, rather than the centre, and is connected to an Ohlins shock unit that runs horizontally along that side of the bike. Positioning the shock this way allowed Bimota chief engineer Pierluigi Marconi to keep the bike´s length to a minimum. Wheelbase is a mere 1390mm, 95mm shorter than that of the standard GSX-R, and 30mm down on Bimota´s own FZR1000-engined Furano.

Other chassis dimensions, predictably, are also on the small side. The SB6 weighs 190kg dry, unremarkable for a Bimota four (and slightly more than a Fireblade) but a significant 41kg down on the stock Suzuki. Rake and trail are defined as 23.5 degrees and 94mm (the GSX-R´s legs are slightly less steep), though the SB6´s fork angle can be varied by half a degree either way, using steering head eccentrics.

The forks themselves are decidedly unusual. They´re ultra-thick, 46mm diameter cartridge units, built by Paioli, with sliders made from a composite of aluminium and carbon-fibre for extra rigidity. Quick-release fittings hold the familiar combination of 17-inch magnesium wheel, Michelin Hi-Sport radial and fully-floating 320mm Brembo discs, gripped by four-piston Gold Line calipers.

If the chassis is almost entirely new and trick then the powerplant is much less so, as Suzuki´s watercooled, 1074cc TSCC motor is employed in totally untouched form. Even the bank of 40mm Mikuni carbs remains, though they´re rejetted to suit the new exhaust system. Bimota claim their pipe boosts midrange power by up to 12bhp, while peak output rises by a solitary horsepower to 156bhp at 10,000rpm.

Any added performance can´t come through extra noise, for when the SB6 fires up its most noticeable sound is a typical GSX-R type whirring and rustling from the engine. Riding position is typical Bimota: low clip-ons, high rearsets, low and thin seat. Cockpit view is a mix of typically neat carbon-mounted clocks and milled top yoke (the fork tops are so wide you´d think these must be upside-down units, but they´re not), standard switchgear, too-narrow mirrors and an incongruously scruffy pair of batteries visible behind twin headlamps.

The SB6 feels compact and firm even by Bimota standards, pulling away with a raw, almost menacing presence that seems to emphasise its status as one of the most singleminded street-legal missiles ever built. Brush the throttle in the lower gears and it explodes forward, lifting its front wheel in first gear in a way the peaky standard bike can´t manage. Even on my first slow-speed pobble through Rimini the bike seemed aggressive and eager to get going..

This is no bike for town riding, and the SB6 felt predictably firm and uncomfortable as it followed our hire-car through the narrow streets. Less expected was the Bimota´s occasional twitchiness when I began circulating a small local roundabout for some photos. The bike could be pulled down onto its side with the ease you´d expect from its racy dimensions, but at serious angles it tended to fall in slightly in a manner that did little for my confidence.

My first thought was that the forks needed considerable adjusting, but perhaps the Bimota simply didn´t suit the conditions. The combination of tight roundabout, uneven road surface, icy crosswind and too much traffic meant I remained stuck in first gear, going too slowly to put much force though the SB6´s suspension or get any heat into its big fat tyres. At the time I was suspicious of the Paioli forks, but on reflection I´m not sure the bike would have felt better if fitted with the considerably more expensive Ohlins units offered as an option on the FZR1000-engined Furano.

Happily, once I got out of town the story was totally different. On normal country roads the SB6´s previous imprecision was instantly forgotten, to be replaced by a feeling of almost total control and security. At faster speeds the suspension started working properly, the fat Hi-Sports got hot and sticky, the incredibly rigid frame began to earn its keep and the SB6 encouraged me to throw it through corners at a pace that would have had many bikes sliding into the surrounding vineyards.

Steering was neutral and light without ever feeling nervous, at least once the bike was up to speed. Despite its lightness, the SB6 felt as though there was plenty of weight over its front wheel. And although the compact Bimota changed direction quickly when required, it showed no hint of high-speed instability even with the steering damper (mounted on the right of the frame) backed off to its lightest setting.

Far from needing radical attention to its multi-adjustable suspension, the SB6 took all the cornering abuse I could put through its chassis with ease, although Bimota´s test-rider Gianluca Galasso (who´d set the bike up) is a fair bit lighter than me. Even when I went into one tightening curve too hot and had to take a precautionary extra squeeze of front brake well into the bend, the SB6 barely twitched before regaining control and carving its way through.

You´d need a racetrack to make this bike´s Ohlins shock and 180-section rear Hi-Sport get close to losing their composure on the way out of corners, too, even though the SB6 puts out plenty of torque. Suzuki´s latest watercooled version of the big GSX-R is strangely weak at low and medium engine speeds, and Bimota´s revised exhaust system does seem to have provided some missing midrange. There´s still not much doing at very low revs, but the SB6 picks up strongly at 4000rpm and accelerates from then on with satisfying enthusiasm.

At most engine speeds there´s no mistaking that the SB6 does retain a slight buzziness typical of the big GSX-R powerplant. The lump is fixed to the frame using two main bolts at the rear, one above and one below the swing-arm pivot, plus two mounts on each side of the cylinder block. Some high-frequency vibration comes through the handlebars and seat, and although it´s not a serious problem my feeling is that the FZR1000-powered Bimotas are slightly smoother.

Most of the time, though, you´re far too busy to worry about that. At higher revs there´s even more of the mindblowing force that the big GSX-R has always been happy to provide. As you flick through the slick five-speed gearbox, the SB6 storms towards its 11,500rpm redline with an urgency that makes you glad of the Brembo front brake system´s ever-reliable power and feel.

This bike isn´t really about top speed, of which the Suzuki has more than enough already. But for the record the slippery SB6, which runs standard gearing, would probably add a few notches to an unrestricted Eleven´s max of around 175mph. It would get there far more quickly, too and more importantly, it wouldn´t have to slow as much for the next bend. With the Bimota SB6, Suzuki´s biggest GSX-R motor has finally met its match.

VERDICT

Bimota´s singleminded superbikes traditionally combine speed, lightweight and racetrack handling, and the SB6 lives up to that reputation. For all those riders addicted to the raw power and feel of Suzuki´s big GSX-R1100 motor, this bike must provide the ultimate two-wheeled trip.

As to whether the SB6 is a better bike than the fearsome FZR-engined Furano, in most respects the decision is too close to call. According to Bimota´s own figures the older model is slightly lighter and more powerful, and it probably has a little more midrange grunt too.

But the SB6 is surely better looking and every bit as rapid in the real world, and at £16,000 on the road it´s also two grand cheaper than the Paioli-equipped Furano (whose optional Ohlins forks add a further £3000).

The competitive price, at least by Rimini standards, has been made possible by Bimota´s intention to increase 1994 production to a record number of around 900 bikes. A third of those will be SB6s, with about 30 due in Britain from the end of March.

So the SB6 will be a slightly more common sight than some previous Bimotas. But this is still one very exotic and exciting motorcycle – bursting with the gorgeous styling, immaculate detailing, leading-edge technology and stunning performance that makes these hand-built sportsters so special.

Get Bimota motorcycle insurance for the SB6.

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