Yamaha YFM50R Owner's Manual page 6

Your ATV was delivered with an adjustable speed limiter. Yamaha recommends that all beginners start off
with the speed limiter screw turned in to limit the amount of speed available while they learn. The speed
limiter screw may be gradually turned out to increase maximum speed as the beginner becomes more fa-
miliar with operating the ATV.
If your child is a beginner or is inexperienced, he or she should take a training course.