Then stay with the stock chain size (that 520 or 530 or whatever your's is) but get a REAR sprocket 2 or 3 teeth BIGGER. This means a new chain but it sounds like you're replacing the whole lot thanks to wear anyway. Right?
If you're just wanting to try it out then cheaply then get a FRONT sprocket only that is one tooth SMALLER. Put it on with the existing chain and rear sprocket and just adjust the tensioner.
Assuming you have roughly a 1:3 front/rear tooth count ratio like most then the one tooth down in the front is the same as 3 up in the back.
Your cruise rpms will be a little higher for any given speed but the acceleration will be better and it *should* give you a bit more for wheelies. Don't expect 2 gear midrange rollon wheelies though. It's just no going to happen with a Kat. Even first gear ones will still need a couple of tricks probably. Like a quick off-on to bounce the front and stuff like that.
It's not a liter bike after all :flip
:laughing thanks!! it's all about the skill, not the engine volume...right