RC212V

In 2007, MotoGP regulations for the maximum engine displacement were changed to 800 cc. The RC212V was a newly designed racing bike powered by a newly designed engine, on a more compact chassis based on the RC211V New Generation. Since the V4 engine has 200 cc per cylinder, the cylinder volume is almost the same as that of the 990 cc V5 engine, which was 198 cc per cylinder. For this reason, a 78° V-bank angle, similar to that of the RC211V, was adopted, and the stroke was slightly extended while the bore remained the same. The size of the engine remained virtually unchanged. The chassis was also designed to be more compact, achieving an unprecedented downsizing. Based on the previous year’s experience and knowhow, the development team believed that the compact RC212V would be able to win in the first year of the 800 cc engine regulations.
However, the 2007 pre-season tests proved them wrong. Ducati had achieved an overwhelmingly fast top speed. This was unexpected for the other manufacturers as well, as the Ducati was more than 10 km/h on some courses as the season began. Ducati’s Casey Stoner won 10 of the 18 races to take the riders’ championship that year, while Honda’s Dani Pedrosa won only two. Four years of misery later, the RC212V would change direction dramatically.
In order to achieve higher output, the RC212V was required to rev even higher, and at the same time, the balance of the chassis needed to be reviewed. The bike was too small, and the settings became too delicate, resulting in a lack of stability. Another problem was that the Michelin tires used by the Honda factory were not as good as the Bridgestone tires used by its main rivals (from 2009, however, Bridgestone became the sole supplier, and the tires were no longer a disadvantage).
Engine bore was enlarged and the rev limit was increased, but by this time the metal springs used in the valve springs had reached their physical limits and the valve train would not last. The testing could not be completed in time, so the management team would conduct motor ring tests at night.
The decisive factor in overcoming this problem and achieving even higher revs was the introduction in mid-2008 of a pneumatic valve return system used in Honda’s F1^TM*2 machines, modified for motorcycle engines. The air springs used in this system not only freed the engine from the problems caused by metal valve springs, but also reduced power loss and expanded the degree of freedom of cam profiles by reducing the weight of reciprocating parts. This allowed revs to reach 17,000 rpm. This was the beginning of serious technological sharing between Honda’s motorcycle and automobile racing realms.
In mid-2009, Honda introduced a seamless transmission that eliminates the need for clutch operation when shifting gears and suppresses the rise and fall of engine speed during gear changes, resulting in more efficient power transmission and a steady improvement in lap times. This technology was developed during Honda’s third F1 era and introduced in 2005, but because of the smaller engine size of racing bikes compared to racing cars, it had to be developed specifically. While the RC212V’s seamless transmission reflected Honda’s knowledge of F1 racing cars, its structural idea originated from the automatic derailleur mechanism used in the 2004 Honda RN01 bicycle downhill racer, which did not require crank rotation when shifting gears.