In 2002, rule changes were introduced to facilitate the phasing out of the 500 cc two-strokes. The premier class was rebranded MotoGP, as manufacturers were to choose between running two-stroke engines up to 500 cc or four-strokes up to 990 cc or less. Manufacturers were also permitted to employ their choice of engine configuration. Despite the increased costs of the new four-stroke engines, they were soon able to dominate their two-stroke rivals. As a result, by 2003 no two-stroke machines remained in the MotoGP field. The 125 cc and 250 cc classes still consisted exclusively of two-stroke machines.