Like in previous years, the 2011 Yamaha WR is available in four models—the 250R, 250X, 250F, and 450F—with only minor differences defining each version. The most notable differences include seat height, curb weight, tire size, and engine type. The WR450F is the largest bike in the lineup and features a liquid-cooled, four-stroke, SOHC, 449cc engine. Meanwhile, the smallest bikes in the lineup, the 250R and 250X, both feature fuel injected 250cc engines. The 250F boasts a 249cc carburetor-equipped engine. All four models feature a reliable electric start with a direct ignition coil system. The 250F and 450F both offer backup kick-start capabilities, in addition to the electric start.