The key difference between the many models is the power that they provide. Novice rider to expert will be able to find the motorcycle that is just right for them with all the choices the 2011 KTM SX makes available to consumers in the market for a competitive dirt bike. The KTM SX 50 MINI and SX 50 offer 49-cc displacement and smaller frames for younger riders. The SX 65 also offers a smaller bike for youths, but includes a heftier engine displacement of 64.9-cc. The SX 85 offers 84.9-cc of power and the SX 105 gets a displacement of 104-cc. Next in line, the SX 150 features 143.6-cc, while the SX 250 gets 249-cc. All the previous engines which are mentioned are two-stroke engines, while the SX F models receive a heftier, four-stroke engine. The SX 250 F, 350 F, and 450 F have an engine displacement of 248.6-cc, 349.7-cc, and 449.3-cc, respectively. The F models are designed for higher performance and are often sought after by motocross professionals.