Actually, it is a time machine to my youth.
This, gentlemen, is the quote of the day.
I built an motorized bicycle for cheap transportation. Actually, it is a time machine to my youth. When I was about 11 a friends father made a bicycle with a reverse acting clutch that tightened a belt from the engine pulley to a pulley welded to a shortened crank. That drove a small sprocket on the right side to a regular front sprocket at the rear hub. A five-horse Briggs provided more go than a kid should have. No pedals required. We rode that thing everywhere and back. One day a really nice bike showed up in the trash at work. A coworker didn't want it anymore. Your trash, my treasure. But still all I did was pedal. After a year or so my wife bought a kit from DAX as a surprise gift. It sure is a great feeling to move through the world without a cage to dull the senses. Did I mention that I built my motorized bicycle for cheap transportation?
Friction drive is definitely the simplest, most hassle-free
way to go. The only drawback is slippage in the wet.
Where I live, it gets really soggy 7/8 mos. a year.
Happily, I fabricated a pretty bomb-proof roller, and
that failing, my Dax converts to a DIY belt drive in
about 30 minutes.
Actually, now I've 2 bikes, one Staton Friction/GX35,
the other, the Dax belt setup/Tanaka PF4000, both
with really low ratios that will cruise lazily at 15 mph
up almost anything.
15yrs old... son you don't need an engine. Your young body is
the best engine you could hope for. Get out there and use it; make
it strong. Build stamina on a real bike. Engines are for fat@$$
old men like me.