The choice between the Razor MX500 Dirt Rocket dirt bike and the MX650 model depends on whether an individual purchaser prefers price savings or power. The primary difference between the two bikes is the size of the motor.
Because the MX500 has a smaller motor, putting out 500 watts, it is intended for smaller riders. According to HomeGear1, the MX500 has a weight capacity of 175 pounds and is recommended for riders age 14 and up. The MX650 is more powerful, with 650 watts. It has a higher weight capacity at 220 pounds and is recommended for riders 16 and up. The MX650 is significantly more expensive than the MX500, which is an important factor for some buyers.