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/128395
MotoGP Tech: Testing, Testing S everal of the top MotoGP riders stayed over at the Brno circuit immediately following the Czech Republic Grand Prix to test new bikes and parts for the 2006 sea- The new Honda RC211Vll made its debut at the Bmo tests. son. Obviously the most important development was Honda and its new motorcycle. though Yamaha, with both Valentino Rossi and Colin Edwards, tested different suspension setups, shock absorbers and tires in the team's first test since Le Mans earlier in the year. But first to Honda. In one of the most curious new-bike tests in recent times, the company debuted its new RC21 IV II at Brno, with the bikes sitting in the garages unused from Monday morning through to lunchtime on Tuesday and permission granted to use the new bikes from 2 p.m. on. The official reason was safety, as there had been some problem on a similar bike in Japan during a test on Monday that caused Honda to have some second thoughts about allowing its top riders to use them. Honda wouldn't say what the problem was but did point out that safety was everything. Once the bikes did appear, it was obvious that Honda has built a completely new bike. Fairing The fairing's cosmetics are slightly different, with different angles and screen shapes designed to improve the aerodynamics over the rider's helmet and shoulders. Instead of the old aluminum fairing stays that are bolted to the frame, the new fairing has an absolutely gorgeous carbon-fiber support mounted at the front of the fuel tank cover. The side fairings are also quite different. Radiator exhaust ducts exist for two reasons: to get hot air away from the radiator and to allow air through the bike that would otherwise be jammed up in fron! of the radiator, causing additional changed the engine's power-producing parts as well, though it would make sense to keep the cylinder heads basically the same, since the series only has one more year to run at 990cc. We can see that the rocker box covers are now carbon fiber. drag. We are not sure whether Honda has added the ductlng at the bottom of the fairing because it is now making more power or because it wants to improve the bikes aerodlynamic efficiency. Even the undertray is shallower, and you can see that all the stickers are slightly smaller and lighter than the previous ones. The exhaust pipe that comes from the fifth cylinder comes out of a different angle as well. Engine We can see that the clutch has been moved down. Attached to the back of the clutch assembly is one of the gearbox shafts, and moving this down, while keeping the second shaft on the gearbox at the same level, means that the whole engine unit can be built slightly shorter. Completely new crankcases are needed just for this mod. What we can't see is whether they've 12 Chassis To go with the new engine, a new chassis has been designed, moving the swingarm pivot forward by about the same amount that the engine has been shortened. As far as we can see, the motor is aIbout 8 to 10 millimeters shorter at the back than before, and the swingarm pivot has been moved forward by the same amount. The weight of the new frame looks to be lighter than before, and Honda is probably using the engine more as a structural support - again with the aim of making a lighter motorcycle. SEPTEMBER 14, 2005 • CYCLE NEWS Swingarm The new swingarm looks like a combination of the 2004 swingarm being used on all this year's customer bikes, as the 2003 swingarm has been used until now on the HRC woriks bikes of Max Biaggi, Nicky Hayden and Sete Gibemau. The 2004 swingarm has a very deep section compared to the 2003 model, but it also incorporates an upside-down linkage. The swingarm on the new bike appears to be the combination of the deeper section of the 2004 design but with the original 2003 linkage. In addition to the new bike, both Gibernau and Biaggi tested their current bikes fitted with slightly shorter versions of these new swingarms. Exhaust The new pipes look shorter, not in overall length but in the distance from the engine to where they join together. This is normally done for an engine that is producing its power higher up in the rev range and again gives the impression that Honda has added top-end power. The pipes on the current bikes were already shorter than the previous year's - so clearly power is seriously on the up. Overall Honda's problem has never been power or speed down the straights: Its problem has been the bike's behavior as soon as the throttle is shut. This could be due to the particular firing order of the V-fIVe, or possibly the effect of very high compression being used to gain the power. In any event, the bike is clearly very sensitive to grip problems once the throttle is shut. Most of the modifications we see on the new bike are to allow the swingarm to be just 8 to 10 millimeters longer and also to allow the front of the swingarm to be much stronger. Mass centralization, the official reason, will help, but just as we saw Yamaha rearrange the architecture of its engine at the end of last year to allow a longer swingarm, Honda is now having to follow suit to try to com- pete with Rossi. In other testing news, Kawasaki tried a new cylinder head and some revisions to its ride-by-wire electronic throttle system. Ducati tried out a new fuel-tank shape, destined to be on the 2006 bike - a prototype unit that it seems will allow the riders to move more easily from left to right, or vice versa in qUick transitions. Carlos Checa also tried an Ohlins fork with a carbon outer upper tube - the same as those used by Loris Capirossi since Mugello this year but it was relegated back to the parts bin after just one outing. Capirossi tried his Ducati without the small outrigger choice that has been a feature of the chassis setup since Philip Island of last year. He did manage to set the fastest lap at Brno, which may be because he used a qualifying tire or possibly through some change to the setup. Ducati was seen with its swingarm pivot out of the bike at one time, so it may have been that the team tried different swingarm pivot positions for better grip. Nell Spalding