Re: Bmx Mb?
look for an old friction drive assist motor... many 2 strokes were made.. they mount on the frt tire,. most are less than 30cc.. don't know how old you son is, but it may also be better balanced to his weight....
when I was -10 years old, I had a 3.5 HP go kart that I could go 30 MPH in, and drift sideways around a sharp turn on an old dirt road. because I wasn't really heavy enough