I have a Kayo Fox 70 I have ported and polished the head kind of aggressively, and welded up a fmf header and muffler. I’m starving for fuel with the pz19. Changed jets. Better but Not enough still. I need at least a pz20 but want to go pwk style would a 22mm be too much?

 

I'm no engine tuner, but bigger jets give you a richer mixture, so more fuel. A bigger carb gives you more mixture, so if an engine is run full throttle and tops out on revs, a bigger carb will give more revs if ports etc, allow. It won't give a richer mixture without bigger jets too. Overly big carbs however, slow the air speed through the carb so it isn't sucking fuel through the jets as hard and will give a weaker mixture, so less fuel.

 

Thank you that was the best explanation I have ever heard. It all makes sense now thank you for that