Cycle News - Archive Issues - 1990's

It's been a long road, but the RC45 finally has the power and handling to contend for the World Superbike Champ ionsh ip, speed traps, as the 184 m ph that allowed Slight to head the trap times at the first World Superbike round at Hockenheim proved . However, while top speed was now good, it w as getting there that was still th e probl em. By the fou r th rou n d a t Monz a, this was re d ressed w ith th e arrival of the tricked -ou t 7-spec mot or, which allowed Aaron to earn the RC4S's firs t-ever p ole in qua lifyi ng. W ith a 14,750-rp m redli ne, thanks to the fanatical attention to reducing fri ct ion and iner tia which m akes this m otor such a mechanical masterpiece, as well as new pistons, titanium rods and va lves, valve bu ckets, ignition chip, and electronically controlled variable-len gth th rottle-bo dy system, the new eng ine finally cured the RC4S o f its acce leration h a nd i ca p . Thoug h the long-awai ted debut victo ry didn' t qu ite co me at Monz a (thoug h Aaron 's second and third augured well), it followed at the next round in Spain, at Albacete, a circu it th at is th e slowest an d twistie st in the Sup erb ik e ca le n d ar . Acceleration was no longe r a problem one lap of Doningt on on a wet-bu t-drying track proved that. This is a jewel of an engine, wi th an appeti te for revs th at yo u feed very fast with just a twist of the w rist. Apart from its d ry-w e athe r performanc e, Ho nd a mus t have been disappointed tha t the re wasn't a single wet race in the '95 Wo rld Superbike season, beca use th e RC4S in its im proved form m ust be the best rain bike in the field . Yes, better than the Vtw in Du ca ti, which has fie rcer torque delivery mor e likely to u nh ook the rea r tire. Instea d, the Hond a has a com p letely linear power cu rve ; it pulls incredibly cle anly a n d sm ooth ly fro m as low as 3000 rpm leavin g pit lane, h eading without a hi ccu p to its near-fift een-grand appointment w it h th e im proved re vlimiter. The new limi te r is much less ag gressive tha n it used to be, and just flutters the engine ra ther tha n cuttin g it out and causing a loss of revs. In reality, even at the Don in gton chicane on a wet track you don 't need to let th e engine ru n below 8000 rpm. An d from 11,000 rp m up to 14,000 the RC45 picks u p revs in credibly fast, bu t wi th that tra demark lazy draw l fro m its Vfou r moto r which makes the fast-fo rward pow er delivery so deceptive - vand invigorating. H on d a engi ne ers ad m it to hav ing experim ented wi th a Big Bang versio n w it h clo se-coupled firi n g ord er in an effo rt to further improve acceleration, s it h asn 't roduced the res ults expected and to date ha sn't been raced in the Worl d Superbike series. Based on my experience at Do nin gton with th e 7-series Cast rol H ond a, th ey really don 'tneed Big Bang: Th e instant response from th e fue l-injected mot or is potent, yet utterly con trollable thanks no d oubt in part to the variablelength inlet system, which opera tes at 12,700 rp m . Un like other su ch systems as see n on the Bel g a rd a Ya maha or works Du cati, both progr essive systems, the Hond a' s w orks in on/off mode by u sin g a servo mot or to lift th e ve nturi clean off its throttle bod y at a computerchi p -se t rpm mark, thu s effect ively shorteni ng the inlet for top-end power . Thi s p rovid es a u seful purp ose for the bi g ger g e ne ra to r fille d no t o n ly to p ower the servo motor but also to effectively increase crankshaft mass to help red uce wheelspi n. As the track d ried an d I could finally g as th e bik e up h ard w i th th e wet Michelin ru bber cu tting th rou gh to the ta rmac, th ird-gear w he elies became a fact of life, wi th the rev hungry V-four mot or spinni ng u p incred ib ly qu ickly th anks to th e reduced internal frictio n. This 7-spec eng ine is also extremely smooth . V-four H on d as d on't reall y vibra te, but there is usually a tingle and a harshness at certain revs that is comp lete ly ab sen t fr om thi s b ik e, eve n wanning it up at fast idle in pit la ne . And there also isn 't the rou gh patch at abo ut 10,000 rpm you get on othe r racing V- fours when th e ca ms begin to w ork , e ither: It 's li ke su p ercharged syrup! .. Simon Cr af ar eventually joi ned h is compatriot Aaron as a full mem ber o f the Castrol tea m to re place Polen, who was gi ven h is pin k s lip a fter Dayton a b e fore the W orl d Superb ik e seaso n started . Crafar got a close- up view of the extra performance of the 7-series mot or. "I only eve r had a 6-series in my bike," says Simon, "which meant it also didn't h a ve th e variable a ir -fu n ne l syste m . When Aaron and I were locked together at Ass en till Corse r took me out, he'd ge t an im med ia te ju mp on me ou t o f tu rn s, as mu ch as 50 meters or m ore . O ur two bikes were exactly the same on top speed, but his definitely accelerated be tter. It was a real improveme nt." Sell ing the swap -over mark for th e va riab le fun n el syste m (w hi ch you' ll not e we weren't allowed to photograph) as high as 12,700 rpm is a su re sign of th e ap petite for revs th is engi ne h as, given that the advantage of such a system is to fallen the m id ran e w ithout comp romising top-end performance. Of th e available si x speeds, the Castrol team ge ars for jus t five at Donin gt on, an d each gear h as four rati o op tions. Gear selection is made w ith the sweetes t-a ction speed -shifter I' ve ever used on a four -stroke, It's smoo th an d light to operate, bu t just finn eno ugh that you have to consciously ta p it w ith your boot rather tha n just brushing it - probably because it works by cutting ou t the fuel flow to the injection rather th an interrupting the ignition (interestingly, independen t sys tems on the RC45). The gear ratios chosen are very close to g e th er, a llow ing yo u to kee p th e H onda m ot oring above 12,000 revs all the tim e. The fou r contro ls for the EFI h a ve be en m o ved to a n e w lo ca ti on under the seat, but the tea m hardly ever n.e eds to alte r th em , sa ys engine man Peter Ben son, who' s justifiably proud of both 6- and 7-spec engine s' reliab ili ty th is season. The only mech an ical reti remen t for either rider all season long was w he n Cr afar ' s engine broke a gearbox sha ft at Sentul - a '94 part that wa s effective ly be ing enduran ce test ed! O th erwi se, a 10o-percen t record - im p ressive for such a high -revv ing packa ge, Cha ssiswise, the RC45 took an equal ly great step forward for '9S, sa ys the Castro I team, who spen t m ost o f '9 4 p la ying with different ch assis setu ps tryi ng to cu re two big problems: a lack of traction, and pow er un dersteer . They also w orked on red ucing the weight to the 356.4-po und fou r-cylind e r limit, w h ich t h ey h a v e n ow s uccee de d in doing. As for the handling, an ingenious - and legal - system of effectively altering the en gine locat ion by mean s of a bo red -out headstock didn' t offer a per manent fix, leadi ng td big changes for '95. The biggest was a switch from Dunlop to Michelin tires, which, however, b rough t a d ow n side inas m u ch as the Fren ch tire compan y's Superbike develo p ment was excl usive ly geared to Ducati, And what su ited a lig hter Vtwin wi th no t as m u ch w eigh t on the front wheel didn't really suit the Hond a, Still, there w as an immediate improvement in handling which got eve n better after a midseas on tire tes t at Alb acet e led to new RC45-friendly ru bbe r fro m Sugo onward '- after which Aaron was never out of th e top four . And it's no coincidence, perhaps, that in both the races he won th is yea r Aaron used a 16.5-inch fron t tire, which gives a better entry to th e comer as we ll as improved ro lling speed in the midd le of the tum, at the expense of some gri p on the way out. Bu t by th en it's the back tire that cou nts, anyway. "Th e fron t en d d oes still push," says Aaron, " bu t it's not as bad as be for e. And an yw ay, I never suffered from this so much as Doug, beca use I sit mu ch furth e r fo rwa rd on th e b ike th an h e does, with my weight on the front end . His mor e upright positio n cau sed him prob lems, whereas Sim on rides a lot like me." And the winner is... eally, the final points table says it all. The Ducati has to be the leader of the pack because it's the most complete package- the easiest and most forgiving of the five works racers to ride, and the most responsi ve and rewardin g. The weight and capacity issues are a smokescreen. Ducatt's evolution of their 851/ 888/9 26/955 desmo V-twin family over the past nine years has resulted in a motorcycle that dominates the World Superbike scene because of its excellence, not through any perceived unfair advantage handed to it by the rules. Just as Aprilia is proving in the 250cc GP class, Italian race engineering has gained its current edge over its Japanese rivals because of daring to be different: Rotary-valve two-strokes and V-twin Superbikes were each scorned as obsolete, rejected as inadequate a decade ago. Yet here we are in 1996 with each at the top of their respective trees. There's nothing to stop the Japanese companies from building a four-stroke twin - or a rotary-valve250. They just have to build one that's better than Ducati's or Aprilia's - or else go their own way and try to win with what they've got. And that's what they're still doing in the Superbike scene, where 1995 saw the RC45 Honda make a big step up in performance. This is now an excitingand effective race bike, underlining the advantages of fuel injection through its high-revving ridability and outright power. Surely Honda's Japanese rivals must soon follow in adopting EFT. Next up in the points table as well as effectiveness is the Kawasaki, where Gobert's idiosyncratic setup can't disguise the allaround excellence of the top in-line four. The new short-stroke motor in the '96 ZX-7R will surely make the green bikes into title contenders again. Yamahadoesn't have such a new trick up their sleeves - yet - but with their tire problems now hopefully behind them, their challenge is to harness the undoubted speed of the YZF motor to a more manageable power delivery and friendlier handling. and perhaps a more focused team operation. Finally, Bimota made a brave return to the World Superbike arena with a bike that needs to have its engine completely reengineered to be both competitive and reliable on the race track or swapped for the new '96 Suzuki GSXR motor, I know which I'd recommend... With Suzuki joining in next season, Aprilia and Cagiva for sure in '97 and maybe Triumph too (if not, surely in '98), Laverda on the horizon and Harley-Davidson waiting in the wings, the World Superbike Championship now has an indisputable claim of being the chosen battleground for all the world's leading manufacturers. Riding the five works racers that fought it out with each other in 1995 underlined one thing: To win races at World Superbike level. you now need a four-stroke GI' racer, not a modified roadster. With the reduction in homologation numbers being introduced next season, this fact can only intensify - and the ones who benefit are we, the customers. Racing really does improve the breed: World Superbike is the proof of that. R >

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