The 2004 MY RM250 has received several revisions aimed at improving the power delivery. A lighter flat-top piston, redesigned exhaust ports, and piston rings have been used, and the carburetor was rejetted, also. At the same time the fork grew thicker, with new shocks and a new rear linkage for better progressive action.
Ergonomics have been tweaked, alongside the brakes, and the bike got a stronger frame and better clutch cable adjustment.