I found this video about a 14 year old boy who built his own bike, and it totally blew my mind. Well, not really, but what it did is to fill me with regret about not doing this with my son.
Enjoy this!
https://www.yahoo.com/autos/this-14-year-old-boy-and-his-home-made-motorbike-129642350152.html
Enjoy this!
https://www.yahoo.com/autos/this-14-year-old-boy-and-his-home-made-motorbike-129642350152.html