I would get him a chinese 110 they are only about 5-700 brand new. The engines last forever. Their main drawback is all the wiring they put on the bikes but it can be easily simplified when it fails. They come in all different sizes 50 90 110 125 . Automatic single speed , semi auto 4 speed , 4 speed with reverse, 5 speed, Kick start, electric start . Iv had experience with about a dozen of them they are easy to work on and parts are super cheap. He will outgrow a pw50 in about 30 minutes they are basicly a gas powered powerwheels. Too small for a 10 year old. These chinese bikes have power for an adult whereas the japanese bikes in my experience are quite anemic. So if you go chinese make sure it has this style engine
