KTM's engines represent the pinnacle of two-stroke engineering. KTM offers several different engine sizes for the XC models: a 125cc, a 250cc, and a 450cc. These engines are liquid cooled and feature TVC twin valve control. Designed as quick revving and tuned for mid- to high-range rpms, all of these two-strokes feel most comfortable when accelerating at high rpms, rather than rocketing forward from a standstill. The transmission is geared to take advantage of the two-stroke's strong mid-range torque, so riders will enjoy moving from second to third gear. Here, the engine offers quick throttle response and plenty of power for competitive motocross events. A Keihin PWK carburetor feeds fuel to the engine and is complemented by a aluminum exhaust placed under the seat.