Cycle News - Archive Issues - 1990's

variable engine characteristics, depending on these two parameters - all with the aim of maximizing traction and imp roving grip under acceleration out of turns. With all this computerization, it's almost a surprise to confirm that the Suzuki still runs the same 36mm Mikuni dual-body flat-slide carbs as before, rather than using elec tronic fuel injection like Honda is experimenting w ith but even the Mikunis are tricked ou t; for these have two electroni c powerjets, one for low engine speeds up to about fivefig u re rev s, the other to gi ve an extra d ose of gas over that. "EFI will come into its own next season, with the new low-lead , 102-octan e fue l regulations," Shenton sai d . "We ex pect a n 8- 10 % power lo ss, w hich fu el -i njected b ik es will fi nd it much easie r to compen sate for, which is why H onda has invested the hu ge de velopmen t cos ts and teams of manpower to get them where they are today wi th it. W e firs t test ed EFI w ith W ayne Gardn er in Au stralia four yea rs ago on an NSR500, an d they're only now gettin g it ri gh t. But th ou gh w e know Cagiva a nd Yamah a are also hard a t work on EFI, it appears Suzuki 'isn ' t, because of the Japanese recession and the budget entailed. We ma y be able to learn from others' mistakes when we do start, but I hope it 's sooner rather than later, otherwis e we really risk beingleft behind." 16 (Above) The Suzuki uses a speedshifter that compensates for wheelspin automatically. (Below) Suzuki wouldn't all ow photos to be taken of the '93 engine -but it's nearly the same as the '92 powerplant shown here. Another electronic ride r-aid fitted for the first time this season is Suzuki's own speed-shifter, which is con siderably more sophisticated than the CTS and other European systems used by Cagiva, Aprilia, etc. The Suzuki sys tem not only de live rs an extreme ly precise, positive chan ge which is neither overly sensitive, so that you change gears withou t meaning to, nor so harsh you can feel it's not being kind to the gea r cluster, it even works well if you short-shift w ide -open, which the CTS, especially, doesn 't like. The Su zuki system is trick bec ause no t only does it have a different length o f ignition cutout depending on the ratio abou t to be selected (this can also be easily varied via an EPROM chip fitted to the control box on the left of the tacho me ter - im portan t for when you change internal ratio s via the sid e-loading gearbox cluster) , but it also compe nsa tes for wheelspin automatically. And it w or ks really well . Only I have to admit that the Lucky Strike team's on board telemetry system (developed by PI Research in Britain, the same company which sup plies all IndyCar and some F-1 car teams with similar systems) told some horne truths about my flat-shifting technique. The 12-channel system used for racing (monitoring rpm, front/rear suspension travel and wheel speed, exhaust valve position, Power Chamber 'position, wate r temp., cornering force vi a an accelero me ter pointing downwards - and most relevantly throttle po sition) showed that Alex Barros had the throttle wide open for 21% of his lap time on a dry track at Jerez, while I s tr u gg le d to reach 10%. Well, there were a few damp patches when I wa s out there - hey , a man's got to have some sort of excuse! The Suzuki's cha ssis is very similar to last year 's XP78 design, but Shenton admits that they've experimented with engin e position, mainly to imp rove the balance of the bike, as well as grip . The result feel s more delica te to ride than the othe r 500s I've sampled this season, as well as being better-steering than the XR78 I rode last year in Japan. It feels like th er e' s more weight on the front wheel compared to the '92 bike, which may be a function of how it was set up, or, more likely, that they've moved the engine forward a little in relation to the wheelbase. The Suzuki definitely changes direction better than its rivals, and has very neutral steering - it doesn't tip suddenly into turns, nor understeer under power out of them. With the ultra-responsive engine and perfect carburetion, it's an ea sy b ike to hold on lin e, and the Kayaba suspension wa s beyond criticism at the speeds I was riding at, on a smooth track like Jerez. This is a bike that insp ires confidence, in spite of its awesome performance. ' But where will they find space to fit the lights? And the brakes? Well, last year I got myself into troubl e by say ing that the AP carbon brakes fitted to Schwa ntz's bike didn't work well - and they didn 't, with either my ha nd on the lev er , or Doug Chandler 's, or anyo ne else 's except the hardest braker in the world - Schwantz. Th e Lucky Strike team had fit ted the bike I was riding with Barros-spec pads and d iscs, and I guess they proved a p oint: th ey w ork - very w ell . Even though mydisc temperature wa s 170 degrees down on Alex's (380 degrees vs 550) becau se I though t I was squeezing hard but obviousl y not hard enough, the bl ack bra kes gave m a gica l stopp in g pow er at the end of the straight, yet with lots of sensitivity if yo u just caress the . lever lightly to cram off some unwanted speed on a long turn. They do take a while to warm up, but once hot (or in my case, I guess, lukewarm) they stay hot, even w ithout shrouds fitted on a 68-degree fall day, and deliver a constant lever pressure all the time, with no servo sensa tion on the lever as you squeeze hard to stop. Okay, why such improvem ent? Firstly, the g rad e of carbonI carbon disc/pad combination used mak es them more user-friendly for normal humans, but AP has also refined its superlative six-p iston calipers hewn from solid metal, and fitted them with articulated pads which provide four leading edges per brake, rather than just two as before. Also, th ey e mp loy a master cylinder which is adjustable for pressure, to d eliver respon sive-yet -total stopping power that is the best I've ever sampled. I wasn't pa id to say that - honest! Just glad to fe t the record straight. But th at's not all . Tho ugh not ye t rac ed on th e bike , Suzuki was testing the latest version of AP's carbon clutch at Jerez, and left it on the bik e wh en I rode it. This ha s been compulso ry equipment in F-1 car ra cing for som e time, and ha s been around th e bike world since 1990. Since then it 's been tested by Cagi va and the Rob erts Yamaha team, as w ell as adopted by Steve Webster for sidecar racin g. Though more expensive than a conventional metal clutch, it's cheaper in the long run because it's more durable, as well as bu lletproof (the more it slips when cold, the hotter it gets and the better it works), and much lighter: Suz uki was testing it for the first time at Jerez, and saved 2.2 pounds compared to its usual 19-plate design. The carbon clutch is a 7-plate d esign with a diaphragm spring like on a car clu tch, and has to be warmed up properly, as I discovered when I wa s the first one to sample it. Trailing round slowly to warm up the tires wasn't enough to get it hot, so the first time I ope ne d it up d own the pit straigh t it slipped at peak revs. But once it was hot, it worked really well, with a light action and no grabbing off the line - as Barros confirmed with a succession of practice starts. Interestingly, taking so much weight off the side of the engine doesn 't affect the flywh ee l effect, nor in turn the torque or engine pickup, no r does the engine need to be rebalanced. The way ahead? Black clutch or not, Schwantz and Suzuki will take some stopping in 1994, even without EFI on the horizon to help them get over the effects of the low-lead fuel to be used next season. They may need fuel injection in the long term, but for now the RGV500 is the class of the pack, a worthy World Champion whose patient evolu tion in to a world-beating motorcycl e is a credit to Suzuki and the Lucky Strike team . It is also unbelievably responsive and rewarding to ride. Come on, Itch-san - where's the road version? CN

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