The Yamaha PW80 has an approximate seat height of 29 inches. Riders weighing up to 150 pounds will fit this bike.
Riding experience
The Yamaha PW80 is an excellent choice for a younger rider with less riding experience. It might even do for an adult rider but it would certainly be at the smaller side.
While the PW80 is a reliable bike, it does have its disadvantages. The bike's small size can make it difficult for larger riders to handle, and the suspension can be harsh on rough terrain.
Recommendations
If the 11-year-old is a beginner or an experienced rider and is small for their age, then the Yamaha PW80 is a great choice.
If they already have riding experience and/or are on the taller side, they might benefit more from a dirt bike with a bigger wheel size and more suspension travel, like the Yamaha TT-R110 or the Honda CRF125F.
