The cylinder on the KTM 250 SX has a bore of 66.4 mm and is fitted with a Twin-Valve powervalve system. The exhaust port is machined for precise power valve function, providing excellent overall power delivery. By using the two supplied springs, the power characteristics can be changed quickly and easily, ensuring optimal settings for different tracks and rider preference. The lateral cylinder head brackets are made of aluminum and reduce vibration to levels of near insignificance.