A statement released by the FIM following a meeting of the grand prix commission at Motegi on Saturday provided one further clue to the format of the new 600GP class, which will replace the 250cc World Championship from 2011.
"Future of the 250cc class:
"MSMA decided unanimously to propose to the Grand Prix Commission the following as from 2011: 4-stroke, 4-cylinder maximum, 600cc maximum engines, free chassis," said the statement. "A detailed proposal will be studied by the other members of the Commission."
The fact that the new machines will be 600cc, four-stroke and with a maximum of four-cylinders was made public at June's Dutch TT.
However, the words 'free chassis' are new, and indicate that some form of standardised engine components will be present throughout the field, but with no such limits on chassis design.
The engine and chassis constructors are still to be announced.
At the same meeting, it was also decided to limit each 125cc rider to one bike from 2009.