Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/128307
Yamaha YZF-M 1 J03 %'RI ) I 02%(R 7 l formance . But t he e ngine isn't as good dow n low as the others, and it definitely has more steps in the pow er band than eit he r the Ducati o r especially t he Ho nda, so you mus t flirt with the revlimite r to keep the pow e r de live ry co nsta nt and pre d icta ble . T he red changeup lights on the dash start flashing at 14,000 revs as an advan ce ca ll, then turn to o ra nge at 14 ,500 rpm , w hich is w he re yo u need to hit the shift lever, just be fore the soft-action re vlimite r flutt e rs the engi ne at 15 grand in pre ss test mode - no rmally, th is is set at 15,500 rpm , it was reveale d late r, and t he fact that pow er contin ue s to bu ild to a 15,350 rpm pea k underlines tha t this is an eng ine that nee ds to be revved . Hard . This w as the only one of t he bikes I rode at Valencia that day, each on their race gearing from the day befo re , whe re I hit a genuine to p gear down the fro nt straight , every lap - w hich says the Yamaha was geared very carefully, and tightly, to max imize to pe nd performance . It's not such a fle xible bike in terms of setup as the Honda and maybe eve n the Ducati - nor as fo rgiving w hen you' re rid ing it. But for sure w hen the M I is just right, and ridden by an expert adept at getting th e best o ut of it every turn, every lap , the n it delive rs. Th e trick is to find the right guy to do just t hat - as in, ciao Valentino . Wh e re the Yamaha sco res is in its light steeri ng and agile han dling by Mot oGP standards, wh ich res ults in a ba lanced fee l with good feedbac k fro m t he qu ite tightly sp rung O hlins suspe nsion yo u just have to w o rry about the hint of oversteer at the apex. O nce you start to get the hang of th e backshifting technique , it stops pr etty we ll if you sq ueeze really hard on the black Bre m bo bra ke s, and it seems ve ry stable unde r braking, w hich is surely th e poi nt of all th e e lectronics. But I have to say I t hink Valentino J 00% ( "" The 990cc inline fou r is extremely compact compa red to Yamaha's own Rl and R7 power plants . The five-valve-per-cylinder motor is a short-stroke design, but that is where the s imilarities between the R1 , R7 and Ml stop. One of the key differences is that the crankshaft rotates backward and doesn't need a secondary balance shaft. In the current configuration the motor revs to 15,500 rpm and produces 240 peak horsepower at the countershaft. II:HIR[]H Y [)IlA INTERV IEW: or Yamaha race e nginee r Ichiroh Yoda, a 20-year veteran of Grand Prix racing and technical second -in-command of his company 's race division, development of the YZF-M I has been an essentiallyfrustrating uphill battle. While pursuing final development of the YZRSootwo-stroke, which won the Manufacturers ' world title for Yamaha in 2000, Yodadidn't become involved with the MI project until midway through the followingyear, since when he's been project lea der and chief race engineer for the firm's four-stroke GP contender. That 's all the more apt, given that Yoda-san'sdebut job with Yamaha Racing Division was helping design the company 's first-ever fourstroke Grand Prix engine - a liquid-cooled 500cc twin-cam V4, which appeared in 198 1 as the rival to Honda's oval-piston NRSoo but was never raced . In fact, this prototype was also the first-ever engine wit h five valves per cylinder, now a Yamaha trademark design. Who better to ask about the hitherto secret details of Yamaha's MotoGP contender? F Q A lc hiroh-sa n, ho w lon g has Yama ha be e n w or king on t he Y2F-M I project? We began early in 2000 working first on the engine, with ~he chassis coming later. Our reason (or choosing (our cylinders is the same as a man looking for oil : He uses his experience to know where to dig, so because we are very familiar wi th the in-line four-cylinder engine layout , which we already use for many categories, and have good experience o f it, we chose this format . Some people think we are w rong, and we do this only for marketing reasons because o f a similarity w ith our street bikes . This is not true - we chose this format be cause we consider it the best choice for o ur MotoGP design . With the R7 Superbike, we reached a good level of performance, but in this category we could not make any drastic development, unlike in MotoGP where we can do w hat we want. Q W h Y did Yam aha not make a full 990cc engine to begin w ith? 32 JANUARY 21, 2004 • CYCLE NEWS Ml M a t:t:e r § A It'strue that at the beginning the enginewas around 92Occ, ~use our concept for the bike was to make it narrow and small, with a good power-to-weightratioachieved througha compaet motor and lightweight chassis, and cylinders inclined forward about 15 degrees for better installation and weightbalance. With thisapproach, we did not need to use full capacity becausewe can always get enough power from around900cc, so most importantis to reduce the sizeand weightof the engine. Also, with onlya 24, liter(6.24 gallons) fuel tankalready and a 22-I~er (5.72gallons) one coming soon, we thoughtmaybefuel consumption couldbe difficult to manage with a 990cccapacity. Butas we developed the machine andgot better performance, we alsoimproved fuel consumption, so that by the middleof 2002. we brought the engineto a full 990cc by increasing both bore and stroke from before. Of course, ~ isstill a short-strokedesign, but not too extreme - just a little bitshorterstroke than our R7Superbike. Inthisform, we now have240 bhp at the crankshaft. with a good linear bui dof power - about 25 bhp or l 10 percent more than lastyear - against the smallerenginerunning on carburetors, but with a smoother torque curve in spite of this. Wh Y did Yamah a use ca rbur e t ors on t he M 1 to begin w ith, especially since t he se are not 50 fuel e fficient an d t he refore produce higher consumption than fue l injection? Q A ) For two main reasons. One is reliability - with a new Q I understand you use two-ring pistons on the MI, with titanium rods and valves - five of them per cylinder. You are one architect of Yamaha's five-valve heritage - did you ever consider making the MI a four-va1vedesign ? 1\ Yes. but onlybriefly - it has been five valvesfrom the very ~ n n ing and still is. The reason is the same as choosing th e in-line four-cylinder format - we have such good experience wit h five valves. But I have learned some positive poin ts about fourvalve design , so we will proceed with investigating this and then co mpare. But for the moment, the M I is still a 20-valve engine, and we use chain drive directly from the crankshaft to an intermedia te gear, which then drives the double overhead camshafts . Q YOU' r e still using va fve-s p r tngs d id you co nsider employing pneumatic valve operation, like Ap rilia? v A Not rea lly. This is another advantage of using five valves ~er cylinder, so the tita nium valves are smaller and very light, and the two springs o n each valve are not so stiff. Present peak horsepower is at 15.350 rpm, so we use a 15,500 rpm revl imiter at present with no pro blems, and I be lieve 16,000 rpm with a 990cc four is quite okay wit h valve springs. Maybe if we get re vs up to 18,000 rpm or more, then we will have to use p neumatics - but not yet . But then , we must throw the engine away afte r every race! ~ngi ne, carbu retors are very easy to adjust quickly and correctly, so this he lps speed up development. But I also believe carburetors are bett er in some areas than fuel injectio n, especially for a racing motorcycle. However, it' s true - they are not so good for consumption, which is why we changed to fuel injectio n at the start o f the 2003 season. The basic system is the same as we used on the R7 Superbike, only with diffe re nt co mponents - we use a Yamaha CPU , but with the two injectors per cylinder coming fro m Marelli, as well as some ot her parts. We work very well with Marelli, so probably in the future we will use more parts fro m them , including the CPU . 40th Anniversa r y Q W hiCh di rection does the crankshaft run - forward, as with most in-line fo ur-cylinder engines, or ba ckwa rd ? And does it feature a balance shaft? A It runs backwards, without a balance sha ft, but with an ~ ntermed iate gear betwee n the crankshaft and dry clutch. T he main reason is the design concept of this engine, which is small and narrow, as well as light, and with strong material for the crankcase, we can run very thin in many places. Backwar d s rotation is important in helping achieve this concept.