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/128409
MotoGP Tech: Sepang Test A s it turns out, the final MotoGP test of the 2005 season proved to be just as interesting and sensational as the rest of the year. Yamaha wanted to test the prototype of the 2006 MI; Suzuki had a brand-new bike, but one where several major decisions still needed to be made before the race bikes for 2006 are actually manufactured; Kawasaki also had a new bike, one that had done a few laps at Valencia in an earlier test, but where several issues still need to be finalized; and then there was Honda, with a pair of new ex-250cc riders who just needed time on the track, with Nicky Hayden, the longest-serving Honda MotoGP rider here, having the job of re-evaluating all the year's bike. At the start of the year, there were questions about the positioning of the headstock, and in the period where the team tried to find a setup that worked, Rossi had several near crashes. Once he had accepted that he would have to make do with a different setup, the situation changed. Toward the end of the year, several reliability issues also raised their heads: Edwards suffered a spectacular engine blowup during practice for the Turkish Grand Prix, and several other engine failures were noted during practice. Yamaha personnel admitted that, as the year went on, the riders were revving the engine higher, and to make more power at those higher revs, some risks were required. alternatives used by his senior predecessors The swingarm design has changed, and during 2OOS. Bridgestone, Michelin and Dunlop were now it is both simpler and stronger. The design is one piece and now incorporates a also present to service their various teams. section in the right-hand spar that has been hollowed out and filled with a carbon-fiber plug to preserve the admittedly small aero- Noticeably, Dunlop has taken over the sponsorship of the Tech 3 Yamaha team, putting its tires on one of the top works bikes for the first time in several years, with James Ellison doing the riding. Yamaha There's no doubt that the Yamaha is an extremely good motorcycle. When Valentino Rossi's on top of it, there is no dynamic qualities of the swingarm. There's also a new chassis. As far as we can tell, the geometry is basically the same, but with a few amendments apparently designed to strengthen the headstock area. Rossi is now running the forks slightly lower on the tubes than he was at the end of 2005, doubt the combination is a stunningly effec- and the new swingarm appears to place the tive one. But it is only really when Rossi's teammate Colin Edwards also gets on the podium that you would say that the Yamaha was the best bike in GP racing. The big design changes were done last axle at the front of its adjustment slot rather than at the back, as on the previous version. Despite these changes, the wheelbase doesn't appear to be different. Most of the fairing is identical to the old year - the crankcases, engine layout and version, but the seat, tank and tail unit is very chassis all combined to vastly improve the bike over the previous year's hodgepodge. different. The fuel tank has been pushed back further and is also lower. During the course of 2005, Ohlins debuted new rear "through rod" shock absorbers that had There were, however, some questions regarding the quality of the build of last 8 JANUARY 4,2006 • CYCLE NEWS much smaller reservoirs. For the balance of 2005, the design was left unchanged, leaving the championship. You can also see that the rubber pipe that used to be part of the enough room for the original larger reservoir crankcase pressure-reduction system, and the lump that used to sit on the cam cover shock to be refitted. On the 2006 version, however, the fuel tank has been rolled downward almost 50mm closer to the rear shock. This, in turn, has allowed Yamaha to build a slightly larger airbox. If you look closely, you can see that the instrumentation cowl is now sitting about 50mm further back, and a small section of airbox rises up in front of it, allOWing the volume of the box to be slightly larger. One change that can easily be seen from the outside is that the tach now reads up to 17,000 rpm. This is not to say that the engine is likely to go that far, but clearly an increase of 1000 rpm on the readout means that somebody thinks that, at some point, they are going to go that high. Having seen Rossi's bike blow itself up on the main straight on the Tuesday afternoon of the test, it is unlikely that they will be trying to go that hard immediately. Carefully looking at the photo of the bike with the fairing off, you can see one or two minor changes on the outside of the crankcases - the most major of which is an additional circular plug on the crankcases between the two main bearing bolts just below the crankshaft. This is most likely a blanking plug for a new oil way stretching across the bottom of the engine, and this is either to deliver additional oil to the crankshaft and its bearings, or is part of an improved scavenge system to reduce tlorse- power losses due to windage. Getting the lubrication of the crankshaft right (enough oil in ttle bearings without any slopping around the crank) is absolutely critical to the reliable high revs that will allow Yamaha to defend has also disappeared. We have to assume that Yamaha has found a better way of reducing pressure in the crankcases, as it is unlikely to have taken this particular item off the bike. Honda Honda was the sole manufacturer to arrive at the tests without brand-new machinery. And the riders in the Honda camp are the big change, as it's "out with the old and in with the new." The new riders include Dani Pedrosa, Casey Stoner, and a recruit from Yamaha, Tony Elias. Standing out rather as the old man among this group, Carlos Checa has been hired into the Sito Pons team for his contacts within the Spanish market and also possibly to provide some guidance to Stoner; his experience in the last two years on both works Yamahas and Ducatis will also provide some interesting feedback. That's not to say there weren't some interesting developments. however. Honda had gone to great lengths to point out that neither Pedrosa nor Hayden is the numberone rider; they are merely both Honda's preferred works riders. Hayden was tasked at the test with trying out all the experimental chassis parts tried by Max Biaggi and Sete Gibernau during 2005. This included a special swingarm only used for four or five laps at Brno in a test following the Grand Prix last August, and the adjustable "long headstock" chassis used at Sachsenring and by Biaggi at Brno as well. It did not appear that Hayden was particularly enthused with any of these modifications.