Im no guru either.
I just widen/port/etc try it, if its needing more, widen more, etc.
Try and get your compression ratio to 15:1
Get another pipe, bullets are not that " performance "
I had and others have 6p's on 50cc
Gear up to 16t or 17t as well, but if you think your low end sucks now, just wait till you get it up to a 17t