Buy replacement parts for the Razor Dirt Rocket MX-500 and MX-650 electric dirt bikes. Wheels, innertubes, battery chargers, tires, throttles, controllers, batteries and much more. The main difference between the two vehicles is the motor, either 500 watt or 650 watt. Also, the MX500 has a max speed of 15 mph with a max weight of 175 lbs and recommended age of 14 and up. The larger MX650 has a max speed of 17 mph and max weight of 220 lbs. The MX650 is recommended for ages 16 and up. Both vehicles have authentic dirt bike frame geometry for a great intro into off-road 2-wheel riding.