Cycle News - Archive Issues - 2000's

For many years th e YZR500 has be en re spected as th e best -handling 500, so it has been Yamaha 's desire to inst ill the YZR -M1 with similar c ha racteristics. To that end , the YZR-M1 utilizes a chassis closely related to the YZR500 . And the choice of an in-line four-cylinder engine was made specifically to complement the chassis. "We consid ered o ther types of fou r-cylinder engine, like a V-fo u r, but the in-line four suits our chassis best, " says Masakazu Sh iohara, designer of the YZR-M1 engine . "It is all new, however, with no relation to the R1 streetbike motor. We also considered more cylinders , but t h is means a heav ier engine, which can compromise chassis design ." Sh iohara is th e creativ e g enius behind many of Yamaha's Grand Prix successes. His first high-profile design was the OW20 in -lin e four 500 c c engine with which Jarno Saarinen led the 1973 500 World Championship. In 1982, he created the OW61 motor, Yamaha's original V-four 500 , and soon after, the fi rs t - ge n e r a t io n YZR500 . Shiohara was als o responsible for the YZR250 powerplant and in 1997 the YZM400F m oto crosser, his first four -strok e a nd th e e n gi ne that revolutionized motocross. No w Shioh ar a is re p eatin g that journ e y , tak ing Yamah a' s GP road race bikes from the two -strok e era into their four- stroke futur e . It is a n entirely original challenge in a n age when rac ing means much mor e th an straightforward horsepower performance . The new four -strok e GP regulatio ns permit a ma ximum c a pacity of 990cc, which allows e ngineers to pro duce exc essive power outputs of well over 200 horse - . pow er , m or e th an c a n be e ffect ively us ed on modern- da y racet racks . The real c ha lle nge is to produc e contro llable performan ce - powe r that works with the rider an d the tires, a nd tha t fits the 22-liter fuel limit (cha nging to 24 -liter for 2002 and 2003 ), "These are our biggest priorities ," adds Shiohara , who ha s been working on prototype engines for the YZR-M1 s ince 1999. "It would be easy for us to make an e n gi ne with more than 220 horsepower, but neither the rider nor th e tire s would be a ble to usefu lly handl e that ov er full ra c e distance . Fuel cons um ption is a lso very im po rtant - 22 liters is not so much , so the engine and fuel s ys tem must manage consumption ve ry efficie ntly ." The YZR-M1 engin e 's c apacity is well under the 990cc limit a n d yet powe r output alread y exceeds 200bhp at around 15 ,OOOrpm. Like the marque's other factory bikes , the YZR-M1 uses all Yamaha 's essential racetrack kit - five-valve heads , cassette-type gea rbox , dry clutch and eng ine -management system . Exotic technology such as pneumatic valves was c onsidered, but rejected . "Po we r ou t p ut is. very s im ila r to our current 500 GP bike , with a litt le m ore a t t he ve ry pe a k , " ex p lai ns Shioh ara. "Bu t there 's a mu ch wid er spread of power and torque output is high, with a very fla t curve . At the m oment, th e engine revs to 15 ,OOOrpm or so, but of course we can go higher if required. "We know from 500 racing that increa s ing peak power is not the way to improve lap times. These b ikes already have maybe more power than riders can really use, that's why we have focused on producing manage able power. We c e rta in ly looked at pneumatic valves and so on , but considered them unnecessa ry s ince we already have more than enough horsepower. Th is is not F1 cars - motorcy cle racing is more about th e riders winning races with controllable power rather than ultra -high power outputs. "I think the four-stroke will be easier to rid e than a 500 because the power delivery is so smooth and lin ear. Everyone who has so far ridden the bike agrees with this." Biaggi and Kocinsk i both enthuse about the YZR-M l 's p erformance. Kocins ki, a 250cc Wo rld Champion with Yamaha in 1990, a former 50 0cc GP winner and World Superbike Champ ion in 1997 , has th e perfect blend o f racetrack experien ce to develop the YZR -MI. "It' s a nice b ike to ride , Yamaha ha s done a good job, " Kocinski said. "T h ey' ve got it to a h igh level very qui c kly. But racing is nev e r ending you 're always t rying to make things better , so if yo u ' re do ing you r job, yo u' re nev er satisfied . We ar e very c lose to 500 perform an ce , bu t right now we've got a little wa y to go . Five hundreds ha ve been a rou nd fo r ye ar s and th is b ike has on ly be e n a ro un d for a few mon ths . It's not easy to be a t a 500, they' re very fast m otorc ycl es th e fastest in the world . You c a n't jus t c o me in and clobber th em s t rai g ht away, but we're getting there . "Th ey improve the bike every time I test. It's a big challenge for all of us and I'm enjoying it. Th ere 's a lot of potential there, it's ju ?t a matter of squeezing it out. The power is defi . nitely smooth, but th er e 's one hell of a lot of it." Biaggi , currentl y contest ing the 500cc World Championship for the Marlboro Yamaha team , has already ridden the bike on several occasions in between his GP co m mitm e nts . The Italian has never raced a four -stroke and must accustom himself to th e diffe rent characteristics, as well as the extra weight. Four-stroke regulations for a four-cylinder machine demand a minimum we ight of 319 pounds - 33 more pounds than current 500cc requirements. "T h e four -stroke seems to have similar power to the 500 , but the character is different," says the Ital ian . "The bike doesn't feel so heavy a little more than the 500, but not too much . The ma in thing I've been thinking about is the base chass is s e t- u p. Th is is j u s t a protot yp e m a ch ine , so nothing is fixed - eng ine p o s ition , we ight d istribution a nd s o on. As John [Kocinski] says , it ke e ps getting better and it' ll be great when we can focus exclusively on the bik e later in the year." Sh iohara is working clos ely with B iagg i, teammate Carlos Checa , Kocinski, Fujiwara and Namba as the d ay s count down towa rd the YZRMl 's rac e debut in 2002. The man in charge of Yamaha ' s c urre nt GP e ffo rt is Masahiko Na ka jima. He was recently appo int ed GP500 project manager and last year oversa w th e factory's securing of the 500 Manufa ctu rers ' t itle as Yamaha Grand Prix manager. His expe rie nc e is a vita l part o f th e YZR -M1 projec t, espec ia lly on th e chassis s ide. "We s ta rte d fro m zero with th is project, with o ne guiding principle : to p roduc e a well-balan c ed motor cycl e ," says Nakajima . "But if yo u co nsi der th a t a ll the to p 500s a re sim ila r in layout a nd d im ensions , th is su ggests that th is is a n idea l confi g ura t ion . Tha t's why we wanted to c o nt inu e usi ng o ur YZR-style chassis with th e YZR-M1 - the e ngine was designed to fit within th e package , not th e other way around . Geometry and d imen sions are very similar to the YZR500 a nd rider feedback suggests we 'have s uc ceeded in reproducing that bike 's c hassis c ha racter. "Wit h th e new fo ur-st ro ke Grand Prix ma chines , we beli eve that tire life is th e most cr uci al issue of all. We are wo rking to p roduc e an e n g in e th at looks afte r its tires all th e way to the finis h of ra ces a nd we a re doing some good work with Michelin on tire develo pme nt. From a tire point 'o f view, this n ew fo r m ul a is a big chall enge , be cause the e xtra speed, weight and torque of the four-stroke means a lot of extra work for the rubber." With around 200 horsepower on tap , wheels p in will obviously be a feature of four-stroke GP rac ing, but Yam ah a engineers do not beli ev e that traction-control sy stems will be a c rucue ' e Masakazu Shlohara designed the M1 's engine , his latest w ork In a long line of high -profile designs from th e Yamaha engineer. cial feature of b ikes like the YZR -M1. Rather their concern is pe rfectl y linear power output to a llow the rider to do exactl y wh a t he wants with th e motorcycle . "Ag a in, this is not F 1," says Shi o hara . " Bike ra ce rs need wheelspin , they use it to help steer out of turns , and in this situati on , there's no doubt that the rider is better than a compute r. Of cou rse , we will have some kind of traction control for especially slip pery conditions, when it's ra ining . for example. " Michelin Gra n d Pri x m an ag e r Jacques Morelli , wh o has a tte n ded several of Yamaha ' s YZR-M1 tests , bel ieves that th e easy -wheelspi nning character of four -s tro ke GP b ikes will furth e r increase the s po rt' s en te rtain m ent v al ue . "It wi ll mak e a great spectacle for the fa ns ," he says , "As t ire manu fa ctu re rs . the incre a s e in torqu e is the biggest fact or for us, it crea tes a lot o f extra stre ss o n th e t ires . But we have a lrea dy s tarted m o v in g in tha t di re cti on with o ur 16 .5-i nc h rear slick. We hav e moved in that direction not o nly beca use it br ings som eth ing to 500 raci ng, but a lso because we were look ing to fourstrokes . Th e m ore power yo u hav e , the ' more rubb er you ne ed on th e ground , and th e 16. 5 has a g reater contact a rea than the 17 -inch." There is no do u bt tha t th e n ew four -strok e regulations have added a furth er e d ge of exci t e me n t to t h e al read y bu zzing MotoGP s c en e . As Yamah a de ve lo ps its YZR-M I, rival factorie s are a lrea dy dev eloping their own ma ch in e ry fo r th e n ew se rie s, in cl u di n g Hon da ' s V-five, a n in lin e three and a V-twin, with m or e on the wa y. For th e next few sea son s , th ese machines will com p e te against the existing 500cc two-strokes to c re a te awesome s ights and sounds at racetracks around the world. Yamaha is in at the start of the four stroke GP racing revolution and the factory a ims to be ready to win when the battle for the 2002 World Championship kicks off next spring. CN n e .... S • MAY 23 , 2001 23

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