The top speed makes sense, there is a lot of machine built around a TINY engine! Inside the trans cover, behind the variator there is a large spacer that prevents the variator pulley from completely opening. this "spacer" can easily be removed w/ basic tools ( an impact driver helps alot) and basic mech. skills. The dealer should charge you no more than an hour labor for this job, however most dealers are willing to do this for no fee due to the quick nature of this mod., and of course the good will that is generated from such a selfless act. You will have to purchase an unrestricted cdi for your engine as the wire mod does not apply to yours. Scooter assasins is the only place I know to get one, and they are rebuilding their web site as we speak. As far as I know the 70cc mongoose was designed to be a TRUE entry level quad. Perhaps your son is just a little too advanced for this model?