It's his bike. If he want's to sell it then so be it.. If he want's to buy a POS Neon then so be it.. Just let him know he's responsible for the insurance, gas and repairs. Who cares if it sits there in the yard, that's all the dirt bike is doing now. It's a life lesson.. Don't give him the choice, but then shelter him and say no if you think he's making the wrong choice. Let him make it and live with the consequences of it.. Looking back he'll realize dad was right. If you say NO and he doesn't get a chance to learn himself then looking back he'll think dads a dick. I guess what I'm saying is.. Give him a chance. If he makes the wrong one then you;re in no worse shape. A dirtbike sitting around that rarely gets rode, or a neon that rarely gets driven. The thing is the neon may give him an incentive to work harder and raise money so he can drive it. He won't do that for the bike. Better he screws this up and learns a lesson now before he does it with something bigger later like a house he can't afford.