>>946268
Turn it into a cafe racer.
This guy has a ton of badass tutorials on building a badass cafe racer.

https://www.youtube.com/channel/UC28gtkJP-bK77M5Qyc3Dn7g

>>946272

I don't really like café, could it be a mocha racer instead?

>>946511
Dafuq

I had a little 50cc piece of shit when I was 16. They make bolt-together "big bore" kits that crank it up to around 65cc for around $150. Never tried those but that's your best bet if you want massive improvement.

You can try tuning the carb with some wider jets. Those are pretty cheap and have a noticeable effect on performance in small engines.

Also, I know the bike that I had was designed for a small child and I weighed 200lbs when I got it so I mixed up the transmission ratio (bigger rear sprocket)and got it a litter more responsive. Lower top end that way though.

Great machine for learning. If it is your only transportation I suggest getting dead ones for practice and fixing them with (mostly) other parts from dead ones. That's a good strategy for any vehicle so you don't have downtime.

Visit forums and STUDY the family of engine to see what you might do with it. Brand-specific forums are far better then /diy/ which is mostly a place to find other places with better info.

Simple bolt-on mods are good (ensure they are proven elsewhere, don't "invent shit" on you main ride) ways to get more power with less downtime for maintenance on your main ride.

If there is another much larger engine which fits you can build another motor at leisure and swap them out.