4. KTM 50 SX, $4099
By far the most expensive machine on our Best Dirt Bikes for Kids list, the KTM 50 SX is also the most race worthy and high tech. KTM 50 SX features a liquid-cooled, 49cc two-stroke engine with a pressure controlled exhaust valve (PCEV), a WP-designed chrome-moly chassis, a WP AER 35 air front fork, and front and rear disc brakes. Like the Yamaha PW50, with which it shares the honor of being named as one of our 10 Coolest Minibikes of All Time, the 50 SX’s centrifugal clutch and single-speed transmission make it easy for aspiring motocross and off-road racers to focus on the track rather than learning how to shift gears. While the 50 SX’s power can be altered to suit varying track conditions, it can also have its power reduced to just 5.5 horsepower with a kit available through KTM PowerParts. The 50 SX’s seat height measures 26.9 inches and weighs a feathery 91.5 lbs.