Cycle News - Archive Issues - 1990's

Cycle News 1995 11 29

Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles

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top-end power the bike now produces, thanks to the efforts of Kadomasu-san and his team. A vital P¥t of this process is tucking yourself away within the bike and behind the fairing, which Okada's distinctive 125-class riding position, with steeply dropped bars and a very closecoupled seat-to-footpegs-to-steeringhead relationship, helps him do. The fuel tank is also steeply indented to allow you to tuck the chin of your helmet down low, between the two creases for the twin airducts leading to the airbox. Lots of attention to aerodynamic detail here, as you'd expect from Honda: It's too bad I'm too, er, vertically overdimensioned to have any hope of ever fitting it properly. The new chassis has apparently resolved the problems of holding a chosen line better under power that Capirossi especially highlighted in '94, says Kadomasu. I had no such complaints when I rode Okada's NSR250 last year: It steered and handled extremely well by my standards (which of course are a whole different story compared to what it takes to race one of these machines at GP-winning pace), and this year's bike with the new frame was equally good from my point of view. Riding a modem works 250 is the closest thing to race track heaven for a wannabe GP rider like yours truly. This is virtual reality made even more real. Nothing else on two wheels delivers so much power, so controllably - you feel you're in charge, not the bike. But still Okada wasn't initially happy with the handling of the new frame, juggling back and forth wi th head angles and offsets, before settling on the original 22.5degree castor angle from Beno onward, and 86 / 87mm trail for faster tracks. For Catalunya he opted for just 83mm of trail, to help it turn better in some of the tighter bends, and with just 1345= of wheelbase, the result is a nimble, responsive steering package that changes direction quickly and easily without being twitchy. A dream race bike, especially with the prototype 43= Showa forks fitted to it, which soaked up the ripples on a couple of the tighter turns. These will be standard fitrnent on all NSR250s next season, whereas this year only Okada had them - the other NSR riders used the older 41= design. But in a decisive change of policy, Honda will allow NSR250 lease teams to use any make of suspension in 1996 - including Ohlins, which equips its Aprilia and Yamaha rivals - rather than be forced to use Showas and pay their apparently very steep fees for race support. The market economy at work in GP racing! Really the only thing I found less than ideal during my quick squirt on Okada's Honda was, surprisingly enough, the brakes - and I've never had to complain about black stoppers before. But in spite of the new Mitsubishi carbon material that Honda has sourced on Br\!mbo's behalf, and which gives notably more-sensitive brake response, the twin 255= carbon discs fitted to Okada's NSR250 didn't impress me that (Far left) Shift action for the speed-shifter equipped sixspeed extractable gearbox was superb. A titanium spring works with the Showa shock to keep the rear suspension under control. (Left) A pair of ducts supply cool, dense air to the airbox. Tucking in fully behind the diminutive fairing Is critical for maximum speed. (Below) A 1ao-horsepower 25O? Seems likely in light of the changes wrought to the 75-degree V-twin over last year's powerplant. The reedvalve motor got new cylinders, bigger carburetors and altered exhausts. (Below) Okada used prototype 43mm Showa forks, while the rest of the NSRs made due with 41mm legs. The twin 255mm carbon-fiber brakes aren't quite as effective for our tester as the prior year's 2551290mm pair. HONDA NSR250 SpecilicIIions EngIne ..........•.............. .water-cooled, singIe-cIanksha 75-degree V-twin, reed-va\ve two-stroIli1k rising-raIe linkage and 8ingIe Showa shock wilIIliIaniIIn spring .22.5 degrees Trd lI3mm 52.95 it Welg/lt , .211.2 potI'lds willi oIt'waler,110 fuel WeIght chlrIbuIIan 53147 % 8rIIIII .Front ...........•........Dual 255mm Brembo Cl.IbOn discs wilIIlour-pislDn Brembo ~ ..... •......••..••..•.•.....•.. .8"r1QIe 196mm HAC steel disc wilh two-pislon HAC ~ HMcI'" WI.................................... .. n-Iwh_ Front 1211IO-17 MlchaIn radial on 3.5O-il. Honda wheel 13161-17 MictlaIn radial on 5.5O-in. Honda wheel Top", ; : Over 170 """ Y_ofcocllltiiiCllOl• ...........................................................1995 o..r .Honda RacIng Coi¥lOlilioi.. ..... . '" SilIIma,,, much. There wasn't the bite, the total stopping power I expected - and the reason is surely simple to decipher: my extra weight compared to Okada's. On last season's bike, he had one 255rnm disc for initial response, matched to a bigger 290mm one for harder stops. Waldmann and Aoki brake harder and later than Okada, says Kadomasu-san, so they still use the 290 / 255mm cocktail, and their UK Dunlop tires apparently are less critical on turn-in for corners. Instead, Okada prefers to maintain corner speed Doohan-style, and has trouble getting a good balance with his Michelin-shod bike on turn-in - which is why he's adopted a Doohan idea, in the form of a thumb brake on the left bar, allowing him to use the back brake even cranked over into right-hand turns, to steady the bike and get the balance right to maintain corner speed. I have to admit I found this more of a hindrance than a benefit - the lever is very close to the bar - much closer than on the Doohan NSRSOO - so you have to figure out a way of gripping the left handlebar with your three outer fingers, while working the clutch with your forefinger and using your thumb for the brake. Takes practice, I guess... ! But what it takes for Honda to get the NSR250 back on termS with Biaggi and the Aprilia is another matter. Leaving aside the Max factor for a moment, it could be that the time has come for Honda to go the same route as Yamaha, and develop a rotary-valve motor for the 250cc class. You won't g~t anyone at HRC to admit they're even testing such an idea in prototype form - but they have certainly considered it, and may, like Yamaha, even be working on it. Riding Okada's reed-valve Honda in its '95 form with added power may b" a buzz for the likes of me, but at GP level the bottom line may well be that the Honda engine in its present form is past its sell-by date. Hang on, though: Check out HRC's development of their new 500cc V-twin, where absolute power rather than the way its delivered will be the crucial factor. Maybe, just maybe, we may see the Big H's twin-cylinder development moving in the opposite direction from what we expected: Rather than the new NS500V being a bigger, butcher version of the existing reed-valve NSR250, we could see the 500 debuting as a disc-valver, and the 250 following as a scaled-down kid siste.r. Care to bet on it? (N

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