2009 Kawasaki KFX 50, Very Clean - A popular youth ATV that lets parents decide. The Kawasaki KFX50 is a great starting point for beginning ATV riders age six years and older. With its wide 27.6-inch stance, full floorboards and environmentally friendly air-cooled, four-stroke engine, the KFX50 delivers solid performance and stable handling to provide a good foundation for young learners.