Cycle News - Archive Issues - 2000's

which right now provide the spectacle ou t there , sudden ly illegal overnight. But neither ca n you make the fo ur- cylin ders so w eak that they can 't com pete - you 've got to search fo r a way of reach ing a level of p erformance on both k ind s of bikes which equals out and gi ves on e k ind as g ood a ch an ce as th e othe r, and that' s wh at we've been do ing. You 'v e got to le t Ducat i continue t o build what they 've been bu ilding but all ow the four-c y linder guys, with clever tun ing, to reach a lev el that eventua lly will surpas s the Du cati twin . And that's what I th in k we fi nally have he re - a set of rules th at doesn' t restrict the fours very m uch , so tha t a goo d tuner will still be ab le t o get the po wer he needs. Bu t it'll be a b it m or e fair tha n what we ha ve at present , and indee d I gues s for the past several ye ars, where there wasn't a le vel pla y in g field . But now I th ink th ere is one with these new rul es. Okay, so let 's l ook at t ho se regulations in close detail. Is it t rue to say that for the twincylinder bikes, which until Aprilia comes back really on ly means Ducati and a couple of slow Hondas, nothing really ch anges? That's righ t - for th e tw in -c yl inders the ru le s ar e essentiall y un ch anged. Those 26 Ducatis out there can still go racing next year, if they want to , and so can the 900cc tr iples - like the Petronas or the Benell i. Same fo r them - nothing ch an ges, unless they go to a full 1000cc , in which case they get treated the same way as the four-cylinder bikes. So h o w do yo u p la n t o pr e ve n t it fr om becom ing a t win-cylinder d es mo one - ma ke race again in the future ? Let's lo ok at the chassis rules, first. A nycha ng es? In both cases the chassis rul es are exactly alike and unchanged from today , exc ept th ere'll be a co m m o n m in i mum w e ight o f 16 2k g [ 356.4 pounds) . That' s because wh en you tr y to put a road bike on the racetra ck , y ou rea ll y have to p ay a lot of attentio n t o the chassis, no matter how good it is to start off with. So what we've sai d is that th ey ca n co nti nue t o m ak e all the c hanges that they 'v e been doin g tradition all y for the pas t 10 years and m or e in Superbike - new forks, new wh eels , new brakes , chassis stiffen ers, better swingarms , n ew sho ck link ages - all th ose things th at m ak e th e bike work well on the racetrack and make it a safe m ot or cy cle to go racing with. So the 2004 ru le changes are 100-pe rce nt foc use d on t he en gine s - whic h mean s y ou do n't plan to make seni or Super sports out of the f o u r- c y li n der 10 0 0s and m a k e e very o n e r un unbraced chassi s and treaded t ires, for example? No - these are raceb ik es der iv ed fro m sto ck , de ve loped fro m a street m otorcy c le with a license tag. B ut th ey are racers, and we've always been m indful of keeping th em that w ay . Look , if you study the technology , a tw in -c y li nd er 1000cc bi k e will never be p ersuaded t o make t he p ow er th at a fo ur- cyl inde r 10 00 cc engine w ill p rodu ce because of the ability to pump air and so on - so you hav e to find some way of equali ng things up by sta rti ng wi th the twin-cyli nder bike as the benchm ark and lo wering the potential po wer output of the 1000c c fo ur. So what we ' ve sai d is that you can cha nge th e du rati on of a camshaft, but you ca n't cha nge the lift. You can rework the cylinde r he ad to let every tuner do his thin g and see if he can ou t sm art th e next guy - that was a big problem with the proj ected k itb ike rules, whi ch got ca ncelled five yea rs ago, bec ause it wasn 't allowed to do a tuneup on the cylinder head other than what the m anu factu rers offer ed . But y ou can't alter the ang le of the valves, and yo u m ust use sta ndard size valves , incl udi ng .th e stem , and the material of the valves has to be th e sam e as sta ndard, so no more ti tani um unless it's on the streetbike , as is th e case, for exam p le, with the new 600 Suzuki. A B ut the weight of the valves ca n be li ghter on t he racebike, unlike 6 0 0 5uperspo rt? That's right - j ust so long as you use th e same gener ic material. W e' re not t al k in g abo ut you must us e exac t l y th e sam e grad e of stee l as th e street motorc ycle, j ust st eel for ste el , not titan ium inste ad of steel. I need to be able to put a ma gnet on both of them and have th em both sti ck to it - I don 't want to be surprised about anyth ing of th at natu re. Look ing at the cra nkshaft, the 1000cc twi ns need a very specia l crank, but the fou r-cylinde r m otorcy cles don't need any th ing so trick - they're rea l m od ern , they're m ad e with good materials, they're going t o be good motorcycles, so wha t we' re sayi ng to th em is tha t you can 't lighten the crankshaft at all, so when we look at th e crank, it has to look like a stock uni t. But you ca n po lish the journals, get them reall y fi nely m icropolished , get a surface treatment on the journ als to m ak e them slipperi er , you can re ba lance the cran kshaft, bu t you can 't put heavy m etal like Mall or y 100 0 in the m to really cha nge the counterweights, but you can fit tit anium co nrod s, if yo u wan t. So th e main bull et points are th at yo u fit any p istons or conrods you want, of wh at ever m at er ial; you c an make the cylind er head an y way you want, including reshaping the combustion cham be r but not alte rin g the included angle of the va lves: you can shave th e com p ression and raise it w ay high if y ou like - but you must k eep standard v alve sizes and materials, and you can't lift the cams any higher than stock, though you can va ry the duration as well as the va lve timing . See, one of th e things I strive for is not t o have motors with real short fus es - we don 't want bikes that blow up and puke oil all over our rac etracks and cost huqe amounts of budget to k eep bolted together in one pie ce. So we've lo ok ed at the pa rts th at need to be strong, and sai d "Go ahead and fix those." But on th e othe r parts we know are go ing to be good enough the way th ey co me fro m the factor y , we've said you can slight ly modify th ese and clea n the m up and make th em nice, but you do n't need to spe nd a lot of money on them . Take the prim ary gear rat io , fo r instan ce. In the rul ebook we've said that ca n be changed on a tw in bu t not on a four, and th e reason beh ind that is that m ost of th e fours now tak e the pri ma ry dri ve gear directly off th e c rank, as part of one of the counte rwe ights . So in orde r t o build th e clutch gear compan ion t o that in a different primar y gear ratio , yo u're starting t o ge t into v ery , ve ry exotic gear-cutting - it sta rts to ru n into exo rbitant amounts of money for not very mu ch reason . So we j ust said the primary gea r on th e fours has to remain sto ck . O k ay , b ut ho w abo ut removin g the balance sh aft, if t here is on e? No prob lem - go ahead and take it out, if yo u like. Again , it 's an easy fix becau se, one, we 're letting the boy s ba lan ce th e engines to a high er leve l than they do in Superstock , and two, it do es let them save a couple of kilos of rota ti ng mass - so wh ile th ey ca n't take lighten the cra nkshaft, we 're saying it's okay to rem ove a good bit of m et al by elimi nat ing the bala nc e sha ft and rebalancing th e c rank t o suit, which gives them som ething there. H O W about trans m is si on ? Is t hat f ree, as at present? T he gearbox is free , but on the clutch we' re say ing that if it comes with a dry clutc h , it has to race with a dry clutch , but if it comes with a wet clutch , it' s go t to stay with a wet cl utch - an d no race kits to swap over, either. But they ca n go to an aftermarket mak er or a factor y k i t to h av e a slipper clutch to give them th e back to rque limiting they nee d - just that if the streetbike cl utch is an oil -bath type, the slipper on e must be, too. Th is is tec hnology that's readil y acc essib le and quite cost- effectiv e, which is ev en reaching production - the Kawasaki 600 has a sli pp er clutch , so I ha ve no problem with that as an affo rd able modifi cati on that makes th e bike easier an d safer to rid e. Q A Q A So now h o w abo ut the most controversia l area, which i s t he intake side of the motor. O riginally, every bike - n o matter how many cy linders - wa s goi ng t o be wearing re st ri ctors next year. Now what? We want ev eryone with 100 0cc three- and four c ylinde r b ik es to be using standard throttle bod ie s, without any ki ts to inc rease the measurement of th ese, as in th e pas t. But what we're go ing to do is t o allow th em to tun e them up a little bit - so they can c hang e th e injecto rs for a m or e h igh-per formance pa rt, so lon g as t hey don 't have to mach ine t he throttle bodies to fit th em - th ey m ust be m ounted in the exact same pl ace as on th e stock bike, thoug h of course th ey ca n ma ch in e th e injector to make th em fit, if th ey w ant to . It j ust has to be in the same locatio n as on the street motorcycle - you can 't physic al ly m o dify t he ac t ual t h rottle bo dy it self . Ho we ver , tho se b ik es with a second ary vacuum slid e attach ment in t he throttle body will be allowed t o g lue those up or eve n take them out, if they w ant. And th en on the b ik es li k e th e Suzuki with a second ary throttle butterfly, we're go ing to let them take the shaft out, the plate out and all th e electric motors out, so all they're left with is what they reall y need for racing - that backup butterfly is just there to give ridabili ty on the street for the guy wh en he' s two -up, tooling around town . It's got nothing to do with racing. On the other p art of the breathing, we 've go t t o ' look at the airbox, and the new bikes which are arriving have bea utifully designed airboxes, which unfortunately have a lot of gizmos and stuff inside them, for the American EPA and such , to cut down on pol lution and for intake noise reduction. We wanted to make them retain the or iginal airb ox shell but be perm itted to clea n ou t all th e stu ff insi de, so long as it didn ' t affect the overall shape of the bo x , and in add ition, at the p lace wh er e th e airducts fro m the fairing attach to the airbo x , we tri ed to find a wo rding whic h wou ld allow m odifi cation of th e airdu ct s th at would effectively allow the m to in crease th e vo lume of the alrbo x, for the one man ufacturer [i. e.: Suzukil ) which is out of k ilter with the devel opme nt cycle of the other Ja panese companies . T he airbox effe ctive ly begins at the nose of the fairi ng , and all the stuff you do between there and the trumpet of the throttle bod y is really airb ox, so w e w ere p rep ared to let them increase th e volume of th e air bo x if they want ed to or felt they needed to , by wi dening th e dia me ter of th e airduc ts . But th at plan was overrule d by a higher authority, so now th e airboxes are free - any modifi ca ti on is allow ed . What was the pu rpo se in originally specifyi ng a stock airbox for the 10 0 0 cc fours, especially if the twin s and 900 t riples had a fr ee choice? Since they we ren't g oing to have special fuel inj ectors or k it th rottle bodies on them , we wanted them to have stock airboxes as well - we didn 't wa nt them to get ca rried away. It's always seem ed as if racin g airboxes are a real trick part - lo ts of priv at eers ca n 't ge t th eir h and s o n th em . But all bik es come with an airbo x as sta ndard - so whoeve r's a cl ever bo y can m ak e a ni ce part and sell t he bike that way for stre et use, too. l t w as a su rp ris e to rea d th e cl au se about revlimits. Wha t's the thinking beh ind that? A s I was studying the MotoGP bikes, in the beli ef that som e fo rms of tech nolo gy if not com ple t e motorcycles will cro ss the street from there to Superbikes in the future, I started to see a little bit of a trend that I didn't want to see on th is side of th e road , and that was 16- 18,000 rpm engine speeds with v ery , very big pistons and very , very short strokes . T hese have terrible po werb and and in my opinion don't have a chance t o be a streetb ik e as is, but they make a lot of horsepower, and it's not hard to envisage certa in design elements coming our wa y furth er down th e li ne. So I sta rte d to p lay with the idea that at a certa in bor e/ str ok e ratio , whi ch we 've A Q A cue I e n e _ S • NOVEMBER 5 . 2003 19

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