We have known for some time that 2010 was to be the last year of the 125cc Grand Prix roadracing class, but until the new Moto3 regulations were published this past November, all we knew about its replacement was that it is to be 250cc four-stroke Singles of some kind.
Salient features of the new class are that its engines are to be for sale to bona-fide competitors at a price of no more than 12,000 Euros—about $15K. Engines will have only one cylinder of no more than 250cc. The maximum permitted bore (no oval cylinders) is 81mm, and rpm is to be limited to 14,000. Engines must be atmospheric; no supercharging allowed. No more than four valves can be used, none of which may employ pneumatic or hydraulic operation. Variable valve timing is prohibited, and camshafts can be driven only by chain. Fuel injection—only upstream of the intake valves—is assumed as the fuel system.
Using the displacement and rpm limits, a maximum power of about 54 crankshaft horsepower seems likely. That’s roughly equal to what the 125cc two-strokes were making this past season.
Each manufacturer is to be ready to supply as many as 15 engines on demand, with other regulations requiring published parts prices, etc. A special rule is provided to exclude “hidden costs” by forbidding service contracts or surcharges for special parts.
The requirement to provide 15 engines is realistic. Back in 1973, the AMA asked manufacturers each to offer 200 machines for homologation in U.S. roadracing. If all nine manufacturers competing during that season had in fact built 200 each, there would have been 1800 motorcycles attempting to qualify for races that usually had no more than 35-40 starters, of whom no more than five or six had any chance of winning!
Realistic also is that these rules deliberately limit sophistication at a time when manufacturers can barely afford the classes in which they are currently racing. While we’d love to hear 20,000-rpm Singles with variable-length intake and exhaust systems and clever variable valve timing, these advanced features will have to await more prosperous times.
Sadly, hardly one of Italy’s storied dohc 125 and 250cc GP Singles of the 1950s or ’60s would be legal under these rules (too advanced?). But Moto3 does continue the long and grand tradition of single-cylinder racing.