PZ27 vs PZ30 Carb Upgrade

[Weldangrind]

This is a quote from your other thread:

Okay, so over the past couple of weeks, ive had to resort in trying the bigger slow jets i ordered, as the 25 still had bad low throttle responce.

The needle jet is fully up so thats not the issue i believe. First i change the slow to the 27.5, which id make it better, but even after tweeking the air screw, it was still hesitant/rough on part throttle where you just need to run at a steady 30 mph (for example)

This week i finally decided to go for the 30 slow jet, again a minor improvement, but still a bit rough on part idle.

Ive only now notice that the bike runs worse the more you open the air jet, so ive ltteraally got it about 1/8 turn from closed. But the more you close it, the worse it idles. Can you actually run the bike with the air screw fully closed? Is that recommended? And what it the best way to be adjusting it. I know that 2 turns out means a bigger jet, but i dont actually know how to adjust it as such.

I'll ask a few questions for clarification. For starters, when you say the needle jet is fully up, do you mean that the clip in the jet needle is in the bottom position? If so, that's likely too rich. Try moving the clip up one notch and tell us if there is any improvement.

You're trying to establish a smooth transition from the idle circuit to the main circuit, so each step requires a proper A/F ratio. My guess is also that the slow jet is too big, but I recommend that you make one change at a time.