Cycle News - Archive Issues - 1990's

~. ROAD RACE World Championshi~erbike Tech Review: Part I • ~ Oln . ... ~ reen. By Alan Cathcart ith the first half of the 1992 Diesel Jeans World Championship Superbike Road Race Series in the books, the FIM's surprise decision at their Congress in New Zealand last October to maintain the same combined weight and capacity advantage for twin-cylinder bikes (i.e. Ducatis) seems to have been partly vindicated. Thanks to some intensive offseason development by the Kawasaki factory, the 'Green Meanie' ZXR750 has shown itself to be all but on a par with the all-conquering Ducatis, in spite of conceding up to 55 pounds and a possible 250cc handicap against the Italian twins. Scott Russell's narrow victory over Doug Polen in a thrilling Daytona 200 gave a hint of this, but paddock sceptics were unimpressed, citing the U.S. open carburetor rule, permitting the Rob Muzzy-tuned Kawasaki to run 41mm flat-slide carbs instead of the 39mm ones homologated for World Superbike. But come the first round of the Diesel Jeans series in Spain, and Kiwi Aaron Slight scotched such doubts by winning his first-ever race in E~ope quite convincingly on his Team Kawasaki Australia ZXR; it was also Kawasaki's first SBK victory in Europe after two seasons of trying, all the more remarkable inasmuch as Albacete was reck-oped to be a Ducati track, with.its tight turns and short straight. Maybe the FIM had more foresight than it seemed at the time? Subsequent rounds saw Ducati redress the balance, but in almost every case the Kawasakis have been snapping at their heels. The Kawasakis are certainly faster than the Ducatis, and are now starting to handle as well, as developmel) t in tensifies. Only the lighter V-twins' crucial edge on acceleration out of turns remains its ace in the hole.. Kawasaki has got on terms with the Ducatis by adopting the same policy as the Italian company in developing a world-cla~s Superbike contender. Whereas the other Japanese factories, as well as Kawasaki themselves to begin with, originally treated Superbike as a class for racerized road bikes, Ducati started from the opposite direction and designed a four-stroke race bike that was capable of being homologated for ihe street, with no inherent compromises being entailed. Take one example: fitting CV carbs makes the bike more tractable and nicer to ride in traffic, but it also levies a 5-8% handicap in outright horsepower. Strangely, Honda seemed to understand the direction Superbike was moving in earlier than-any of their oriental counterparts, hence the advent of the RC30. But then they got complacent and instead of revamping the bike completely as Kawasaki did for last season with the ZXR, they allowed it to run qn basically unchanged til it was well past its sell-by date. Atypical for the Big H - but an error they now acknowledge and are about to rectify very shortly. Indeed, both technically and organizationally for the World Superbike series, 1992 is a transitional year. Ducati is still maintaining its supremacy for the time being, but Kawasaki W 16 has closed up on them and thanks entirely to the amazing Fabrizio Pirovano, Yamaha has stayed in contention, too. Honda has completely dropped off the pace, Bimota has given up, for the time being at least, preferring to concentrate their limited resources on developing a 500cc V-twin Tesi-chassised GP racer which they eventually hope to sell for the street, and the new water-cooled Suzuki GSXR750WN is still being developed into the contender for overall honors it will surely become soon - provided Suzuki management takes the necessary step of forming, or appointing someone else to run, a full fact<>rybacked Superbike team to act as the sharp end of their four-stroke development, rather than simply hand out race kits and a few special parts to anyone who wants to pay for them. That approach works well enough at importer or dealer level: as Kawasaki, Yamaha and Honda have now all proved, you need a more concentrated commitment from the parent factory to achieve success in'the Superbike series, and nothing illustrates this better than the formula for Ducati's current dominance. With three levels of factory support, the Italians have aU the bases covered: a small handful of full factory lease bikes to spearhead the company's challenge for top honors, a couple of dozen near-replicas for sale to privateers to fill out World Superb ike' grids or challenge for National titles, and a bigger-volume production racer for the. enthusiast with less deep pockets. The first two versions (the works 888 and the privateer Corsa) are four-stroke race bikes distantly derived from the third (the SP4), a street bike capable of being transformed into a racer but which also serves the vital purpose of hOUlOlogating all three types for Superbike racingl Ducati chief engineer Massimo Bordi admits to having planned this rational and clever game-plan very carefully, and deserves every credit for having done so - thus at the same time pointing those who wish to emulate Ducati's success in the same direction. So while 1992 sees Ducati still on top but under strong pressure from Kawasaki and a single Yamaha; 1993 will see a big upheaval iIT' the world of Superbike racing. Kawasaki will have a completely revamped version of the ZXR, with a pressurized (not forced, which is supercharging, and forbidden!) air induction system reported in early testing to have yielded significant horsepower improvements of the order of 5 bhp and more. They already have flat-slide carbs, though but Yamaha doesn't, yet: the all-new FZR750R (OW02?) due to be launched at the Cologne Show at the end of September will have flat-slides, though, as well as a completely new engine design, still fqllowing the same basic architecture and with five valves per cylinder, however - but maybe gear drive to the camshafts? - and an all-new, more GP-style chassis: The surprise is that neither Yamaha nor Kawasaki reportedly plan to fit fuel injection even to their top-of-the-line Superbike street racer - but Honda most definitely will. The RC30successor due to be launched at Cologne this fall will be completely new, still-with a V-4 motor but with the gear camshaft drive moved to the side of the engine like on the prototype NR750 race bike, to permit a much straighter inlet track design for the more compact, round-piston motor. Tbis will reportedly be available in two basic versions, one with CV carbs for a less costly street model, the o.ther with EFI to form the basis of the bike Honda hopes will regain for them the World Championship of four-stroke racing: SBK. The chassis is all-new too, or-course, with a more modern geometry based on the Suzuka-winning RVF750, but the fuel-injected engine is going to seJ new ,standards of customer technology for two-wheeled Japanese products. It also }Von't be cheap! Ducati is well aware of the threat time being Bordi insists the 66mm stroke gives the best possible compromise between torque and top end. Fitted in an all-new, more compact tubular steel chassis designed by Massimo Tamburini and clothed in less bulky, more svelte bodywork, the 916 will be launched at Cologne complete with single-sided swingarm, giving a clue where Ducati intend ii to be mainly used: Endurance racing, run to Superbike rules at world level from next season. But if the Japanese threat intensifies, and the 888 falters, you can guess the rest. And Bordi can still increase capacity to 1000cc anytime he likes, especially as the 502 Ducati single presently under development has shown the viability of doing so. Which leaves the rest. Whether the' World Championship Superbike Series sees any new makes in the immediate future is hard to say - but for sure the bikes exist in prototype form. Sneak photos have been published of the 'Harris-framed Harley-Davidson Championship leader Doug Polen's Ducati is readied for practice, complete with tire warmers. Polen and his fellow Ducati riders have started to feel pressure from Kawasaki. from Japan, of course: they've been waiting for it to manifest itself at this sort of level for the past year and a half, which is just how long the new 8-valve Ducati 916 has been more or less ready for production. With a 94x66mm motor rather than the 94:x64mm configuration of the current 888 (or Bimota's long-stroke 95x68mm version in the Tesi), the 916 is a step closer to the Mille 8V that Ducati could theoretically produce, though for the Superbike that's due to be ,launched this fall, with GP-style alloy chassis, fuel injection, four valves per cylinder and a narrow V-twin angle, but whether Harley will build the bike in sufficient numbers for it to be homologated for world-level Superbike racing remains' to be seen - they on'ly need build 25 street versions for U.S. National Championship Superbike homologation, it seems, but at least 200 for the FIM series.

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