The end of the two-stroke motorcycle is nigh. Word from this weekend's Dutch Grand Prix is that the 125 GP formula will be swapped for four-stroke 250cc engines in 2012 or 2013 and the class will be renamed Moto3. According to MotoMatters, these engines won't be based on existing 250cc four-stroke motocross engines, but will instead use an 81mm bore, effectively making them a one quarter of a 1,000cc MotoGP engine.
125 GP is the last major international racing class to use two-stroke
engines, Moto2 replaced 250 GP racing with four-strokes this season.
MotoGP itself is due for a formula shakeup in, swapping its current
800cc maximum capacity for 1,000cc with a maximum bore of 81mm. That
bore size will make the 250cc four-stroke in Moto3 higher revving than
the typical motocross engine of the same size.
Of course, with the potential for MotoGP and the smallest class of GP racing to use engines based
on a modular architecture, you can't help but speculate about the future
of Moto2, which currently uses a spec Honda CBR600RR engine. Honda's
contract to supply that engine runs out in three years, leading to
speculation the class could switch to a 500cc formula to bring it inline
with the two other classes.
Again according to MotoMatters, there's already talk of how to keep
engine costs reasonable for small teams, especially as Moto2 is proving a
financial burden too large for smaller players. That talk is apparently
headed in the direction of engine suppliers making a minimum of 10-15
engines available per season with the max cost of those engines fixed
Interestingly, there doesn't seem to be agreement on what this new class
will be called, with some pointing to Moto1 and others Moto3. The
consensus does seem to be that power will go up slightly to compensate
for a similar increase in weight, meaning lap times should remain about
via MotoMatters, GPOne, MCN