Cycle News - Archive Issues - 2000's

Manuel Poggia!i's Aprilia RSW250 and Roberto Rolfo's Honda RS250R-W crank,thenwas improvedvia the HRC factory kit to produce around 15 bhp better than that inthe form raced lastseason by Roberto Rolfo, leaving around a 10percent deficit between the two nominally equalbikes for the difference between crankshaft (the japan way) and gearbox(as ese in Europe)horsepower readings. There are twinpowervalves per cylinder on the Aprilia controlled viathe firm'sown PokerSystem , APRILIA R5W2Sll TEI:HNII:AL: Champion Contents Dutch engineerJ Witteveen hasbeenAprilia's raceboss since an 198 - the year when the Italiancompanyjettisonedthe customer 9 tandem-twin Rotax engines, which had earned the company's debut GP victoryin 1987with L Reggiani, infavor of Aprilia's oris own rotary-vatve 9O -degree V-twin motor, which since then has powereda succession of title-winni g RSW250 machines. n During the past 15years, Wltteveen has been responsible for the evolutionof ApriliaCorse into the direct European equivalent of Honda'sHRC, whose 89 in-houseemployees developand construct around fiftyracing motorcycles of allkinds eachyear. Some 40 or soof these racebikesare destined for customers, the rest for Aprilia's own factoryriders- and of the 18Apriliaridersin 250 GP last season,four of them were mountedon RSW full-factory machinery, vvith Poggiali, Tony Elias, Rantly de Puniet and Fonsi Nieto dulyfinishing in that order at the top of the table. Except for the peskyRolfo Honda in the runner-up slot, Aprilia wouldhave hada cleansweep. However the fact that Aussie Anthony West , scored a privateer victoryinAssen on a customerRS250 Aprilia underlined the effectiveness of the customer bikes, which cost Euro85,000Oust under $104,000) each, especially when improved bythe factorykit, which isavailable to the dozen or so Aprilia privateers taking part inthe wholeof the worldseries. This raisesthe hardwarebudgetfor a full seasonto Euro 250,000 (about $305,000)per bike, says Witteveen• but that sum palesin comparison to the minimumfigure of twice that amount needed to run one of the RSW250 machines - thoughinfacttwo of the teams runn ingW·bikes are each spending in excess of a million you feel you can trust the Aprilia's track manners implicitly and just get on with worrying about how to cut down on lap times and impro ve your race position. In spite of its class-leading engine performance, it's a bike you feel secure enough aboard to start push ing your own personal boundaries with, knowing that the Aprilia will allow you to deliver whatever you ask of yourself. Tha t's a perfect ride . By comparison the Honda I rode at Catalunya required a more committed riding style and d id n't seem to have as much margin fo r error as the Aprilia. Forgiving, it's not - but what the Japanes e bike is, is light-feeling , slim, fast-ha ndling and slightly smoother coming on the throttle when exit ing a tu rn in terms of the pickup and pow e r delivery; it' s just that there's not as much of it, and what's there is de livered over a noti cea bly narrower powerband. Th at's probably a function of H RC engineers' trying to counter the Italian bike's undoubted horsepower advantage, be cause though like the Aprilia the Honda also pulls well fro m 9000 revs upward, it prod uce s maximum po we r a thousand revs lower, at 12,500 rpm, and is all do ne just 500 revs highe r. It falls off the pipe quite steeply, and the re 's very littl e overrev. A 4000 rpm powerband means you must be ext reme ly precise in the way you ride - hard to do in the no -p risone rs arena that is 250cc Grand Prix racing - and also d ictates even more careful setup of th e internal gear ratios for each circuit than the less peaky but also more powerful Apr ilia. T his not on ly accelerates notab ly be tt e r than the 28 APRil 21, 2004 • CYCLE NEWS euros (over$1.2 million) a season, revealsjan, andone of them over two million (over$2.4 million)! Andthat's justfor renting, not buying, the bikes - and it doesn't include logisticsand ridercosts. However, the differences amongthe various levels of RS250 tuning available from the Aprilia Corse a la carte menu are subtle, engine management system incorporated in the dash. "Thisis new for 2003,and we developedand makeit ourselves," says Witteveen "It'sthe same ason the four-stroke race . bikes,and everything is included inone small electronic box engine management. data recording, powerjet powershfter, igni. tion, tachometer, warning lights. temperature gauge, evenfuel injection on the four-stroke. It's a full deckof cards!" However,although alternative ignition maps are stored in the system,there's no provision on the 250 for the rider to swap among them in a raceaccording to tire wear or a change in condi- tions,as there indeed is on the 125Aprilia. He has to stop at the pits to do that on the 250. The carbon fuel tank hasa fuel pumpfeeding a 25:I mixture from it to the pairof 41 mm Dell'Orto flatsli e powerjet carbs d housed in the trick carbon-fiber airboxon the rightsideof the engine (oneitem we weren'tallowed to photograph whenthe bike was stripped!), and the pump is alsoused to maintain a high ambient pressure inside the airbox, with the aimof improvingthe incoming charge.Surprisingly, Apriliahasused the same design of exhaust pipeon the works bikesfor the past three years. "We keep the exhaustconstant, then work on different cylinder porting, different ignition, different other items," says Wrneveen. "We knowwhat works, and thisreducesthe variables so we can concentrate on improvements." The cylinders havefive transfer ports and twin exhausts, with carbon-fiber rotary valves. Aprilia used three different designs of aluminum twin-spar evenif Witteveen admits thatthe chassis, swingann, crankcases and "power parts" (by whichhe means the cylinders, heads, chassis, vvith a carbon-fibersubframeincorporating the seat for the R5W250 in 2002, but lastseason justone - it ran out of exhausts, etc.) are allslightly different between Wand customer adjustment on the final '02 one so madea new frame, which resolved that problem, still with the same engine locationbut versions. "But the parts are interchangeable between all the machines," he declares. "We onlyhaveone designof bike, not a trick works special that no one can buyvvith a completely different engine from the more humble customer model, likethe japanese do." Speaking of which, he also insists that there'sno difference at allbetween Poggiali's factory -run bike, maintained by veteran Italian tunerRossano Brazzi, and the other threeworksmachines even if Toni Elias in particular was so convinced Poggiali hada faster bike after the Mugello speedfest that he madea formal complaint to Witteveen, requestingthatJ anspend more time in the Repsolffelefonica team's pit than previously! "They allfour had the exactsame equipmentthroughout the year," claims Wltteveen, "except Nieto useda lot of 2002 parts, becausehe didn like some things about the 2003 bike. Thatwas 't hischoice- but ifthere was a difference in performance between Pogg iali's bikeand the others, it camefrom Rossano Brazzi, who is more experienced than anyone else in the class about working on thes engines. He's the difference. We have a development team e inNoaleworking allyear round on new pansand improvements to the bike, but when these are ready to be raced, alifour riders receive themat the same time. However thereare no bigsteps , forward, onlymanysmall steps,whichyou get from constantly workingto makethe bike better. It's an advan tage to be competing in 125 aswell, because we usethis engineasthe basis for development, sincethe 250 has the same power parts as the 125 - it's just a double-up." In'03 R5W250 form, the 54 x 54.5mm 9O-degree V twinAprilia rotary-valve enginevvith twincontrarotatingcranksdelivered 104 bhp at the gearbox, at 13,500 rpm,states Witteveen. That's considerablymore than the factory RS250R-Wversion of the single-crank 75-degree V -twin reed-valveHonda, which started out life as a customer bike, vvith 92 bhp at the 40th Anniversary vvith an extreme front-endweight biasof 55/45. Thison a bike weighing bangon the class Iookg(220 Ibs.) minimum, thanksto allthe carbon fiber including the 3.75/5.50 in. wheels made by , Aprilia. "Forwardweightdistribution has been increasing allthe time the past few years," Witteveen says. "I thinknow thisisasfar as we can go without losing a good balance - thoughvvith the rider in place, we havea SO/50 layout." All four ridersapparently ended up vvith almost identical steering geometry, whichon Poggiali's worldchampion bikesees the adjustable headangle set at 23 degrees, vvith loommof trail for the 42mm upside-down Ohlins forks. There's a new, beautifully fabricated aluminumswingarmwith a revised link for the Ohlin s rear shock, delivering a wheelbase of I350mm on Poggiali's bike, whichJan saysis a little longer thanthe others, becauseit's the way hispredecessor as 250 World Champion, Marco Melandri, preferred the bike, and when the Podgemovedup to the class from 125, he did all hisearlytestingon Melandri's motorcycle and justgot used to things being that way! The wholeisenveloped in Aprilia's typicaily voluptuous bodywork, which for the Australian GP developeda rash of holesin it to counter the lateraleffectson stability of Phillip Island's gustyvvinds. "It makesa bigdifference," asserts Manuel Poggiali."Yo can u even feel the vvind blovving through the holesaround your hands goingdown the straight! It looks peculiar but it works." , The voluptuous Aprilia looksanythingbut peculiar, viewed as a whole - indeed, this isarguablythe best-looking motorcycle on the GPgrid in anyclass And,on this bike,show is most definitely . backed up by go, as Aprilia has demonstrated byvvinning seven 250cc world titlesvvith the bike in the past 10years. No wonder Apriliaisthe odds-on favorite to makeit three in a row in 2004 against the stiffenedchailenge from its Honda riva ls.

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