Moto2: FIM outlines 250cc replacement plan

Four-stroke engines of 600cc and four cylinders maximum look to replace the current 250cc two-stroke class, with the FIM and Dorna calling for manufacturers to express their interest in the plan before the end of July 2008, just over a month's time.

The absence of any mention of either production or prototype engines in the announcement came as a surprise, as it has always been assumed that the GP world is bound not to use any 600cc engine block that is currently being used in World Supersport, a championship solely for production based bikes whose rights have been franchised by the FIM to the FG Sport Group run by the Flammini brothers.

It is believed that FG Sport has a specific deal with the FIM that prohibits a Grand Prix bike using anything but prototype parts, something that was brought to a head when WCM made their own MotoGP engine at the start of the 2004 season.

That engine was built from a variety of production parts, but initially with an engine castings that were standard Yamaha R1, and therefore not prototype.

The bike was only cleared to race when prototype castings had been created for it.