The MotoGP World Championship will officially return to 1000cc engines for the 2012 season, announced Dorna today following a meeting of the Grand Prix Commission in Geneva yesterday.

In a brief announcement, it was announced that in 2012, the MotoGP bikes will have a maximum displacement of 1000cc, a maximum number of four cylinders and a maximum bore of 81mm.

Featuring a limit on the bore size is believed to be in a bid to limit to rev output, effectively forcing the engineers to settle for a lower rev range and decreasing the maintenance costs over the course of the season compared to the current 800cc engines that rev over 18,000rpm in some instances.

“The main changes we have decided on are new rules for the MotoGP class. We will have four cylinder engines, four-stroke of course, with a 1000cc maximum, and the bore of the cylinders will be 81mm,” explained FIM president Vito Ippolito to MotoGP.com. “This base will give all the manufacturers the opportunity to start work. At the beginning of next year we will produce the new rules in a more complete format, but that is the basis; 2012 will be the year of a new era of MotoGP.”

Dorna CEO Carmelo Ezpeleta is also looking forward to the rule change, which is set to see the premier class abandon the 800cc limit that was imposed for the 2007 season.

“It was a very important meeting to decide the future of the MotoGP class,” said Ezpeleta, also on the official MotoGP website. “It’s a very important measurement because with this we can have all the characteristics of the engine. This has been approved and between now and the start of the 2010 season we will have another two meetings to define the rest of the specifications for this new class.”

Interestingly, the bore size of 81mm is larger than all of the current production 1000cc engines that Superbikes utilise, and with the MotoGP engines set to be based from production engines in 2012, expect engineers to be experimenting with the stroke length (and more) in order to extract the most out of the engine’s 81mm bore.