Cycle News - Archive Issues - 1990's

RACER TEST (l eft) NSR500 project leader Kazuo Hond a (left ) wo rked hard to overcome rellablility problems encountered by the sw itch to unleaded fuel . Crankshaft life was reduced dramatica lly. (Above) The change In fuel spec if ication for the 1998 seaso n saw horsepower drop fr om some 195 bhp to 183. The acceleration is less fierce on the Dooha n Screamer tha n in the past, mak ing it easier to manag e and less beastl y to ride. Here, the mu ch fiercer pickup from a closed throttl e of the Big Bang motor had th e rear tire spi n n ing a n d tra ct ion impa ired - at pr ecisely the kind of tum w he re th e close- firi ng-order engine is supposed to excel. But the jerkier throttle response unsettled the bike, mad e the back wh eel step ou t cranked over in the tum, and even if you ma nage to control tha t oka y, it still . makes it unstable u n d er acce le ra tio n around the long left-bander afterward . However, pickup is better from lower revs: 8000 rpm bri ngs serious punch ou t of a turn on the Big Bang , wh er e th e screamer need s 9000 revs showing on the ta ch before it co mes o n really strong, wi th a super-powe r sector starting at 11 grand . But once yo u ge t bo th engi nes spinning. the Doohan bike d efinitely accelerates better, an d I have to say I reckon that with his 250cc GP heritage: Biaggi would ha ve co me to g r ips qu ickly with the screamer motor, and worked it we ll. Too ba d he didn' t get his '98 deal tied u p in tim e to ha ve th at option, ac cording to Honda... "The high-speed powerslides you had were a typ ical Big Bang p ro ble m this year:' said Okada at deb riefing time. "T he e ngine cha racter cha nged with unleaded fuel, so that now side slide in faster turns is always a problem. But, if you can keep the revs u p, the screamer is defi nitely better - and mo re con trollable, also - than before. Power transition is be tter as well with th e sc rea mer m o tor, thou gh bo ttom power is still goo d with the Big Ban g, excep t throttle resp onse is some times jerky. But mayb e Motegi is a screame r course ." 32 Co uld be, wit h all th e tight turns a t the ends of long stra ighta wa ys, Formul a On e-style. Take the horsesh oe tum o ne, for exa mple: Braking deep into that at the end of th e pits on th e screamer mo tor m ean t havi ng to u s e the Brembo ca lipe rs / Mi tsubishi-carbo n-discs bra ke package really hard, because it defi nitely doesn't ha ve as much engine braking as the Big Bang motor, and for someo ne like me, who is used to racing four-st rokes, that comes as a bit of a cultu re shock. But zap down throu gh the gearbox as you squeeze the brake lever, keeping the rev s up a ro u n d 10,000 rpm in bottom gea r, and you' ll be rew arded wit h ph enomenal yet controllable acceleration as you pick the Honda up to use the fat part of th e rear Michelin for the dri ve ou t. But do the same with the Big Banger later, and get ready for that tire to sta rt goi ng wa lka bo u t at th e sa me re vs. Strang ely, it felt less controllable, and the sa me thing wen t for th e w heelies th at inevi tably come as you shift into second, and third, and then gas it up ha rd . (It's worth noting the SRSOO V-four isn' t fitted wi th a wide-open power- shifter for upward changes on w hat is quite a stiffactio n gearbox. HRC thinks it's too tou gh mecha nically on transmissions tha t ha ve quite a lot of gear-pinion und ercu t to harness all that power.) While th e sc reamer seem s to pull wheelies even easier; they feel longer and less violent - yet it surel y picks up engine speed faster, opening the d oor to superior acceleration. What seems easier at first to ride may not actually be so in reality. Yet in a faste r medium-speed turn, like the righ t-hander at the end of the lon g, downhill Motegi main stra igh t (w h ich st o p ping fo r is a real tes t o f brak ing prowess - yo urs, as we ll as the bike'sl), the Big Ban g bike was definitely bett er, because you can accelerate into the bend and keep up quite a bit of mom entum. Thi s makes th e bike feel lik e a twostroke su perbike, with a sa tisfying gru nt from down low th anks to the closed- up firing order, as well as good pi ck-up, since you di dn't have to close the thro ttle in the apex and provoke that bru tal, sudden respo nse which was so unsettling . W ha t all th is m ea ns is that, mu ch against my expectations and contrary to its past record , I much pr eferred riding th e Dooh an "Version B" NSR500 (Version C is the BB, Versio n A the 9O-degree orig inal-style mo tor w hich Honda also tested for possible rebirth a t the end of 1996). We'll never know exactly what HRC' s clever engineers did to turn the tireshreddi ng tearaway into a sexy screamer, but electronics surely play a big pa rt in it, as well as po rt timin g. Ka zuo Hon da insi sts tha t the tw o motorcycles are identical apart from having d iffere n t cra n ks hafts a nd a ltered cu rves for ig ni tio n a nd ex ha us t-va lve map s. "However," he says, " tho ugh both engines have the sa me maximum horsepower and peak torque ou tpu ts, at the sa me rpm , settings a nd pe rfo rmance vary depending on the engine revs and throttle ope ning, since these are linked to the ignition and exhaus t-valve cu rves." In oth er word s, since you use differ ent amounts of gas in different situ ations o n eac h typ e o f en g in e , that' s what mak es the technical difference between the two - quit e apart from the most cru cial ingredient of all: the right hand of the guy sitti ng in th e sea t. And as I'm th e first to recogn ize each time I ride a SOOcc GP bike, some right hands are more, urn , prod uctive than o thers! Becau se grappling with kee ping the Honda's front wheel mo re or less near the ground as you exit a tu m like the last ch ica ne a t Motegi , t he bi ke p o int e d s o m ew h er e near th e direc tion yo u intended it to face, the back wh eel sort of hooked up and you r weig h t ki nd o f where it' s su p posed to be, w hile at the same time trying to focus on the road ahead and concentra te on making dean gearshifts on the non-wide-open-variety sp eedshifter, well, ju st remember ne xt time you see a four-bike battle for 500cc GP supremacy that these are unquestionabl y th e most ph ysical and most demanding ra ce bikes in the world to ride, and doi ng so at close qu arters like we saw so many times last season mak es you live in awe of the.men w ho d o so. Thou gh now more powerful but also heavier , four-stroke su pcrbikes aren't so bru squ e and viole n tly responsive as these two-stroke megab ikes - making it less vital to clenc h yo ur arms and pull yo urself forward under acceleration, to help you kee p your weig ht far forward to stop the fro nt w hee l from lifting too far and losing time . These are extreme ly physical bikes to ride ev en remotel y hard, the weigh t transfe r at the other end of any straigh when the carbo n brakes deliver stoppin power unheard of by modem superbik s tandards, tax ing yo u r bod y' s s ta rn in z still further . But get either NSRSOO singing hard i the top thr ee gea rs, like flat ou t in fifth a 12,500 rpm ( there's good overrev tc 13,000 if you ne ed it , to ho ld a gea between turns, bu t pow er tails off abo v 13,200 revs - but at this level everythin is relativel) or at least hard on in top gea down Mot egi's main straig ht, and ther is no m ore-e xhilaratin g bu zz on twr w heels . It ' s e nough to m a ke you a po we addict... Yet this is all wi th a bike that, i either form, is de tuned slightly from 1997 thanks to the switch to unleaded fuel las season. This meant that for the first tim, in many years, Honda's chassis develo ment was aimed at he lping riders maxi mize comer speed - a fact the new Show. suspension package that took some tim to d ia l in at the sta rt of the vea r wa . ai med at ass isti ng . (Perhaps this is o n rea son 250cc World Cha mpion Biaggi ada pted so quickly to 500cc GP racing?) Th e ch an ge to unl ead ed required H RC to int rodu ce m a jor red esigns 0 cylinder head, cylinder, exhaus t cham be r, silencer, ignit ion and especially p is ton and rin gs (five or six d ifferent typ . are used, d ep ending on the circu it and its power d emands), all to accommodat th e new g reen ga s. A 5-percent powe loss was Honda's d ownsid e, but apparentl y Yamaha probably lost on ly 2 to 3 percent - though of cour se they had less to start with! Whatever the case, the two bikes are now pr etty eve nly matched , says HRC sta ff, who claim th e Yamaha chassis is presently better th an th e Honda's, perhaps because of th e di ffer en t inertia of Yama ha's twin-cra nk eng ine, compared to the NSR5OO's single-cra nk layout. Still, if this is seco nd best, I'll take it. Honda' s 500 is still the be nchma rk GP race r of its generation, a fact Max Biaggi's sta rt ling challenge for the World title in his debu t year underlined . Let' s face it: Wo uld he have had the sa me success right ou t of the box on a Yama ha? I' m not th e on ly o ne w ho th inks not. But looking back to 1992 and the first year I rode a Big Bang Ho nda, it seemed an Eticket rid e to a promised la nd , wh ere d reams of a t last bei ng able, as a Joe Average racer, to ride a works SRSOO Honda to something distantly approaching its true potential came tru e. By taming the fierce power delivery of the screamers I'd sa mpled for the past seven yea rs and never got close to masterin g - especially not with the inherent handling prob lems of a bik e like Lawson's '89 title winner - Hond a had deli ver.ed the key to a forbidden world . But now, w ha t bega n as a Doohan d are to his rivals has turned history o n its side, and thanks to the hard wo rk and inge nuity of HRC' s engi neers (with a little help from the FIM ru le change) , th e sc rea me r Vfour has again beco me a se rious o ption for Hon da's 500cc riders to consi der in n 1999. Yesterd ay once more.

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