Cycle News - Archive Issues - 1990's

FIRST RIDE apart from a new exhaust system with a shorter collector and revised silencers, we have significantly improved midrange performance, and have five percent more maximum horsepower at peak revs - up from 138 bhp at the rear wheel on the old SB6, to 145 bhp on the new bike. We also have a substantial increase in top speed: In homologation tests, the bike was trapped at 292 kph (181.04 mph), but that was only on a 2km (1.24-mile) airport runway, with insufficient room to accelerate and stop to best·effect. ''I'm convinced we can beat the Honda CBRll00XX's 303 kph (187 mph) top speed in magazine tests with this bike on a banked track like Fiat's Nardo test venue in Southern Italy, and we'll be trying to prove that the SB6R is the fastest production street bike in the world there sometime next spring, when the weather warms up." Absolute top speed is pretty irrelevant in real-world riding, though, unless you live in Germany and even then only By Alan Cathcart Photos by Kyoichi Nakamura 14 reaking the 1,000-bike production barrier with a single model may be no big deal for the likes of Honda or even BMW, but for a class operation like Bimota - where every bike that comes out of the Italian fa cto ry is essen tially hand-built - it's a manufacturing milestone that's happened only once in the company's 23year history. It was in 1996, to be exact, with the SB6. It's no exaggeration to say that the sales success of the Suzuki GSXRllOOengined SB6 has beeh the key to Bimota's survival. The SB6 fueled the prestigious Italian marque's incredible comeback from near-extinction to fulfillment of the hopes that company surgeon Walter Martini had when he took over operation of the stricken company in May of 1993. Back then, Bimota was down and out saleswise, with a mere 382 bikes sold out of the 7OD-plus built in 1992. Martini realized Bimota needed a flagship mainstream product to prop up the company's balance sheet, as well as earn profits which would underwrite the costly development of the avantgarde Vdue fuel-injected 500cc twostroke. So, he got Bimota engineering boss Pierluigi Marconi t ast-forward development of the SB6, which duly made its debut at the Milan Show that November. Thanks mainly to the SB6's runaway success, Bimota's prod uction doubled to 1,230 bikes in 1994, and in 1996 broke the 1,500 barrier - with the SB6 at:counting for the lion's share of production both then and now. The fact that the Vdue exists at all - let alone is about to unleash GP-level, two-stroke performance on Joe Streetrider - is thanks to the SB6. Be grateful: Bimota management surely is. Of course, nothing lasts forever, least (Above) The 1997 Bimota SB6R possibly the world's fastest production street bike. (Right) At the heart of the SB6R lies Suzuki's GSXR11 00 engine, a package that along with a new airbox and intake system produces a claimed 145 horsepower. of all at the leading edge of twowheeled technology or in the fave rave fashion scene, both of which contrasting worlds Bimota serves in roughly equal measure. The Italian custom bike maker has become pretty adept at staying one step ahead of overnight obsolescence, when yesterday's flavor of the moment suddenly becomes today's candidate for the classic bike hall of fame. Just wait, it'll happen sooner than you expect even to a modern-day biking icon like the Ducati 916. Which explains the debut at the IFMA Cologne Show last October of the Bimota SB6R, a heavily revamped update of the original SB6, which is no longer in production. Actually, that's not entirely fair. The new version is more of a new model in its own right than a mere face lift - as discovered when I was handed the keys to the first prod uction version the day after it returned from completing homologation tests, making it ready for sales liftoff. One might think from casting a swift eye over the new bike that the only major change that Bimota has wrought on the R-model was to give it a new set . of clothes and a different paint job. Wrong. One will have a different opinion after the first twist of the wrist, as I found out while accelerating out of the factory yard and past the new building on the other side of the road into which Bimota has moved its machine shop and R&D I race department (in an effort to free up space in the main factory to further increase production). You immediately notice the engine response is much crisper and more immediate than on the old bike, leading - ahem - to a spot of embarrassment for yours truly. See, the throttle action is also so light and precise that I, er, made the mistake of assuming the SB6R had been fuel-injected, just as the GSXR750 powered SB7 had been. See, it pays to read the press kit before riding the bike because the bottom line is that, no, it isn't fuel-injected, even if it feels as though it is. The R-model still wears the same 40mm Mikuni Slingshots as before only that Bimota has made radical improvements to the entire performance of the GSXRllOO motor, as engineering boss PiLu Marconi was eager to explain, once he'd stopped laughing at me for asking if he'd used the same fuel-injection package as on the SB7. "The biggest improvement we've made on the SB6R is in the airflow to the carbs," Marconi explained. "First we increased the size of the fully sealed airbox, and optimized the inlet flow through new intakes above the new, bigger radiator in the revised bodywork. But the most important change was to pressurize the float chambers of the carburetors to the same level as the airbox. Why? Because this delivers a better flow of fuel, which is already primed for mixture with the incoming air, and allows us to run 10 percent bigger main jets, as well as obtaining - well, yes, the same throttle response as a fuel-injected bike. "With no other mechanical changes, on Sunday mornings on the right stretch of autobahn. But much more important is the vastly improved pickup from low revs at part throttle openings that the SB6R's new induction system delivers, as well as the midrange response while . hard on the gas at higher speeds. Though the various chassis changes only reduce dry weight by 2.2 pounds from before to 418 pounds, the R-model really does accelerate more crisply and eagerly than before - and considering the old SB6 had every right to'wear the crown of undisputed speed king of the streets, before the CBRllOOXX came along, that's really saying something. But, whereas before you had to get the Suzuki motor wound up above 7,000 rpm to really get going when combined with the Bimota exhaust and induction system, now it really starts to motor more than two grand lower - and it's more crisp and responsive in doing so. The SB6's rather soggy midrange has now been filled in, which makes the Rbike more rewarding to ride because you don't have to use the five-speed gearbox as much. It also makes the changes to the running gear quite welcome. Chief of these is a revised chassis design, still Marconi's distinctive SLC (Straight Line Concept) format which debuted on the SB6, but with the whole lower part of the frame combining the swingarm pivot and shock mount now consisting of an alloy casting incorporating a frame brace, an idea which came about a year ago on the YB9SRI and

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