Connor----if it were me-I would start with the power valve first (remember it is a power valve) when I had it good and clean and working right if the bike still does not feel right-then I would be looking at the carb. I would stay on the fat side of jetting (may not make peak hp).
I dont know what oil you use for pre-mix or how you mix it, or how you keep it or how old it is. Also what fuel you use.

For me in the old days I used the same jetting on my 250 with pump fuel or race gas (vp 104) my bike ran better on rave gas but money was real tight so alot of times I had to run pump fuel.

Just keep it simple--------also do you put the oil in the gas can first or the gas in the gas can first????
That can make a real big differance.
One more thing the power valve is gummed up-how about your air filter-how offen do you clean it??


TxTom