Next year, the 125 class of motorcycle Grand Prix racing will be replaced by a new class of 250cc single cylinder four-stroke machines to be known as Moto3. This year's final 125cc season is the last remaining category from the original classes which comprised the inaugural 1949 World Championship and it shows that even the tragically myopic FIM is capable of change. Yesterday Honda unveiled its production machine for the championship at the Gran Premi Aperol de Catalunya. The 84 kg, 35.5 kw, 13,000rpm NSF250R will cost EUR23,600 in Spain (with 18% VAT included) and will be sold worldwide from December 2011, no doubt becoming the mainstay of affordable racing as the RS125R has been until now.
The Fédération Internationale de Motocyclisme has taken a ridiculously long time to replace the irrelevant two-stroke 125 class and its blatantly anti-competitive handling of electric motorcycle racing lost it a lot of fans too - all clear signs that the Fédération Internationale de Football Association is not the only Swiss-based sporting body in need of some serious introspection.
The broad outline of the Moto3 class is that engines will be 250cc four-strokes singles with a maximum bore if 81mm that must last a minimum of three races and will not cost more than EUR10,000. Unlike the recently introduced Moto2 class which uses Honda 600cc engines exclusively, there will be no single engine supplier for Moto3, though each manufacturer will be required to be ready to supply a minimum of 15 riders with its engines. Austrian manufacturer KTM is another with a machine and engine on the drawing boards for the category and it'll be interesting to see if Yamaha also joins the fray.
Though Honda looks like it will play a major role in the new Moto3 class, it will no doubt have some mixed emotions at the demise of the class it has had such a long and technologically wonderful association with. Honda has won 164 Grands Prix and 15 World Championships in the 125 road race class, eleven of them with the RS125R.
It was in this class in 1959 that the name Honda first became known outside Japan when it entered several twin-cylinder 125 machines in the Isle of Man round of the world championships.
Within a few years the Honda name was gracing world championship winners in all categories, but it was the 125 class in which Honda first distinguished itself, and the exotic engines it created are still legendary today - the Honda works machine of 1966 comprised five (33 x 29 mm) cylinders, and produced 38 bhp at 20,500 which isn't all that bad considering that the current KTM and Aprilia machines, produce not much more than 50 bhp, and they're two strokes with a half century of knowledge extra in their design.
The Honda RC148's pistons weighed just 34 grams each and the head diameter of the valves was 14.5mm. Legendary tuner and engine builder, Nobby Clarke, at that time in Honda's employ, used tweezers to put the Honda valve gear together.
Honda has been a long-time supporter of the 125 class, building and selling its first production road race machine, the MT125R, in 1976 progressing through to the current RS125R, which saw two of the three factory Honda MotoGP riders (Dani Pedrosa and Andrea Dovizioso) win their first World Championships on the bike.
Hence it's not surprising that apart from the liquid-cooled, DOHC, 249 cc engine, the Moto3 machine is very closely based on the RS125R. The frame is very similar to that of the RS125R and both the brakes and suspension are identical. Even the fairing is a close replica with an identical drag coefficient.
The engine has the intake facing forward and the exhaust facing rearward, with the cylinder angled backward 15° in order to help concentrate the machine's mass. It utilizes titanium valves for both the intake and exhaust to reduce frictional losses due to weight. Further frictional losses have been reduced by coating the cylinder bore in nickel silicon carbide (Ni-SiC) and offsetting the cylinder centerline.
Like the RS125R, the 6-speed gearbox is a cassette design, allowing gear selection to be quickly changed.
The NSF250R is manufactured by Honda Racing Corporation, and will be sold (along with replacement engines and spare parts) through the Honda Motorcycle dealer network. It will also be available through GEO Technology, an official supporter of the Moto3 class.
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