Cycle News - Archive Issues - 1990's

U RACER TEST Seo« Russell's Muzzy Kawasaki ZXR750RSuE - - -;e _er_bik e 22 ly raisi ng th e rear ride hei ght. A t th e sa me tim e, wid e r fo rk offsets a re em ployed to reduce the trail fro m last year's kicked- out 108mm to a quickersteering 102mm, which combined with the narrow head angle and accentuated front end weight bias (up to 55/45% on Russell' s bike, compar ed to 52/45% on Phillis's), delivers a bike that takes qu ite a bit of comin g to terms with. It's intimidating - that word again! at first , until you even tually figure out .tha t every thing is done for a purpose, and the only way to make the Kawasaki respond is to get on top of it and show who's in charge. This is a bike that has to be ridden very forcefully - a Ducati is much less physical, by comparison - but which delivers the goods if you do . I'm no Superbike superman, but the 1:57 lap which Fred Merkel's watch had me lapping Zeltweg on the Russell ZXR would have been good enough for the top 30 in q ualifying for the World Superbike round the day before - some indication of its miraculous powers. This only happened after I convinced myself that it was safe to ignore those speed wobbles up the hill from the chicane. If I hit one of the bumps in the track at speed (my speed compared to Scott's speed), the front wheel chatter over the ripples on the off-eamber downhill left-bander after the Bosch Kurve, wasn't anything to get nervous about. Mr. Russell was watching from that very spot, havin g cycled up the hill on hi s brand-new tr icked-out mounta in bike. :'Yeah, same thing happened to me in the dry there," he consoled. "Maybe a suspension problem, or it could of been the tire - either one. But those new Ohlins forks work really smooth most anywhere else, plus that they're stiffer, being thicker than the old ones; they work good under the new brakes we have this year ." Ah yes, Scott, the brakes, thanks for reminding me . And what brakes: personal milestone time - simply the best. I have never ridden a bike, even a factory 500 GP racer, which had such absolutely mind-blowing stopping PC?wer at your disposal as the Muzzy Kawasaki has this year w ith the latest 310mm ca rbo n N issin discs, and the new si x-piston Nissin calipers. The best brakes I've ever used on a motorcycle, they deliver the ability for the ZXR to wait it out going into corners w ith a 44-pound lighter Ducati V-twin, yet hav e remarkable sensitivity, allowing you to caress the lever like with metal discs, to knock off a little cornering speed if you enter a turn too _ up high all the time. Th is means using the ZXR's p reviou sly - weakes t point a lot - th e gea rbox. For tu na tely, thou gh, th is has been co mpletely changed for 1993. "There's no t one part the same on the cluster," Doyle said. "An d it's all better qu ality, too, with a differe n t shift d rum and d etent spring, too. We' ve see n an end to our gea rbox p robl em s fro m last season." And me to mine, for unlike last year on the Phillis bike, I didn't miss a single gear in more than a dozen laps on the Ru ssell bik e, and th e shif t actio n is sharper and more p recise, too. There was no speed-shifter when I rode the bike, th ou gh , and being suc h an easy revving motor, I'm sure it wou ld benefit from one. It mu st surely be on the list, but in the m eantim e you can n ow ch ange up w itho u t using th e clutch, unlike last year. (Above) The Rob Mu zzytuned Kawasaki has been transformed from a fourstroke street bike into what is basically a fourstroke Grand Prix bi ke. (Right) Russell's cockpit. The engine revs to a 14,200 rpm redline. enthusiastically, or need to change line to avoid a slower bike. It's noticeable that unlike other users of black brakes, the Muzzy bikes always run shrouds on both fast and slow tracks, in ho t or cool weather, presumably en suring a constant braking performance with no element of fluctuation. Russell sets the lever close to the bar at rest, but then as you heat the brakes up the first half lap, the lever fattens out - and then stays there, without any of the variable servo-type effect of other carbon systems. And though th e six-piston calipers give a fierce bite when needed, they also have that low-pressure sensitivity, perhaps because of the differentia l size of each set of pistons - the best. Though the new Ohlins forks will allow you to brake quite hard on the lean, I wasn't abo ut to find out the hard way just how close they'll come to the Bimota Tesi standard, so I ended up carrying quite a lot of corner spe ed into some of the turns. Tha t's where the Muzzy ZXR's geometry starts to tell : instead of the more ponderous steering of the Phill is bike (which even in improved form la st se as on w as a lot more of an effort to lift from side to side in the Zeltweg chicane), the Russell bike changes direction extrem ely well for a big in-line four . Yet once you get used to the change in geometry, it's actually not as radical as it seems a t first , it allows you to take wid e, sweepin g lines around ZeItweg's fast cu rves witho ut the front wheel feeling it wants to tuck under. Hit a bump on the lean, and it does start to shake its head a little at times, probably a function of having quite a lot of weight up high, but gen er all y the s teering is neutral, and notably lighter than befo re. Th e extra weight on the front wheel help s maximize grip as you tum into a comer - at a price that perhaps you pay on the way out. Even I, at a reduced pace, found thatyes sir, the ZXR likes to spin the tire and play tunes on the exhaust note as you switch on the power out of the chicane . At first I thought th is, and th e speed wobbl e that sometimes appeared up the next sort-of straigh t, might be due to the sus pens ion being too soft for my extra weight. But it turns out I'm only a couple of pounds heavier than Russell, so that's not the reason. Fact is, this is just an extremely potent, accelerative motorcycle that motors out of turns like it's been fired from a rocket-launcher, and ge tting a tire and suspension setu p to cope must be a constant challenge. I know riding it certainly is - and tiring mentally, as well as physically. Russell must be a very fit man - and Aaron Slight, too - in more ways than one. Interesting, by the wa y, that the team uses a big 6.25-inch rear wheel, whereas last season Phillis found that using a smaller 5.75-inch ri m (with Mich elin tires, of course) de finitely gave better traction . The guilty party in all this is that sopotent Muzzy motor, which not only has a notably even more linear power delivery from 8000 rpm upwards than before, . it revs even more freely than last year's bike did . Tha t leads you to attack the 14,200 rp m re v- limiter as a matter of course, and though there isn't the kick in the power de livery there used to be from about 12,000 rpm up, the constant build of power up to the 13,800 rpm peak means you need to try to keep it revving The power that the World Superbike champion- elect d eliv ers is available to any other Kaw asaki team, says Doyle: "We use the same parts as last year, which have now become the '93 race r kit, meaning we ha ve a stock crankshaft, kit camshafts, valves (inlet is 1 mm oversize), springs, two-ring forged pistons, 2.5 mm longer rods, and close-ratio gearbox, and the kit igni tion, which still isn't programmable. We use a Muzzy p ipe which d elivers more top-end power (4 hp from 12,000 rpm upwards, at the expense of the same amount off the bottom end), and that 's about it." Yes , apart frorri the porting and flowing of the cylinder head, the constant experim entation with inl et lengths, carb settings, cam timing and exhaust pipe de sign, which delivers not only more power but also a different power curve, is the so rt of work very few. private teams have the time, the facilities or the budget to accomplish. So, look, listen and marvel at the Muzzy Kawasaki. It's an Ultimate Racer: the fastest and mo st potent carburetted four- stroke production racer ever, refined into a title-winning superbike with the manners of a GP racer, ridden to seemingly certain championship success by a man who has proved its master - Scott Russell. In doing so, Russell proved that green is the color of the 1993 World Superbike sea son, a yea r in which the old axiom that to finish first, you mu st first finish, never came truer. The Muzzy Kawasaki is fast, reliable and no w handles like a true race bike - it may well yet be a match for the new-generation Ducati 916 and Honda RC45 contenders next season. 01

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