"jetting guide" question

[getherejune]

Hi all-sorry in advance if this is a stupid question. Following the jetting guide on here for our new to us kdx220. Question is, after Inda goes through how to determine if you have the correct pilot jet (we don't-need to go down to a 38), the next part goes through how to fine tune your airscrew. says once you have your a.s. set to where it is idling the fastest, then its time to adjust the a.s. for the best throttle response. Then it says "set the idle back down". So, my question is, do i use the air screw or the idle screw to do that? For example, if we go down to the 38, test for a correct pilot again, and lets say we are 2 turns out and golden. To move on and get the best throttle response would i use the a.s. or the idle screw to bring it down to a good idle, as at 2 turns out we are idling the highest. (I have had 2 strokes before, but following the guide that Indawoods layed out has made me start to understand jetting way more-I can tell he was a valued member here for sure). Thanks all for the help

[bufftester]

Not a stupid question. The first round of settings (with the idle screw turned in to keep the bike running) determines your pilot jet size. Once the right PJ is in then (assuming you haven't moved the idle screw) turn the idle screw down and then ride and make VERY small adjustments on the air screw to get your best throttle response between idle and 1/4 throttle (i.e.: cracking the throttle open). Once done with all that you're through the hardest part!

[getherejune]

Awesome. Thanx tons Buff. That helps out a ton. No, we havent moved the idle screw from where we had it from initial setting that we used to see if we had the right pj in. (We adjusted it a bit to make it idle slightly faster as Inda said) Our initial jets/settings were so wonky from the PO, we had to start from scratch. Jetblock gasket was toast, airscrew was like 4 turns out-probably because the PO was trying to compensate for the bad jb gasket letting more fuel in-and the idle screw was turned all the way in and was tight. So we replaced the jb gasket, replaced the 42 with a 40 to start out, and i backed out the idle screw about 1 full turn to give us some wiggle room. Replaced the plug, started at 1 1/2 turns out on the a.s., and adjusted the idle screw to give us a slightly high idle. To get the idle to its highest, we had to go out 3 1/2 turns on the airscrew, so putting in a 38 pj tomorrow and will do the check again to make sure we have that part right.

So, since my main goal this time around with a 2t is LEARNING and not just following directions, can you explain why turning in the idle screw affects the idle? I know that turning in the screw raises the stopping point of the slide-In my mind i know that doing that should let more fuel in, as the needle isn't going down quite as far, but i thought that the needle only affects about 1/4-3/4 throttle, and this is at idle. So i know i'm missing something here. I've google searched it a ton, and everyone always talks about the air screw, and if they do mention the idle screw its just mainly an afterthought-so please throw some knowledge my way if you have a sec! Appreciate the help for sure

[SS109]

Yep, adjust the idle speed screw and then test. IME, I always end up 1/16 to 1/8 of a turn richer (back in) on the air screw for best throttle response.

[getherejune]

well, u had that spot on ss-went back in about 1/16. Running way way better now-not as much smoke and way less spooge. Still some drool, but i think that is just from letting it idle, dorking around with the as, and then riding it only up to 1/4 throttle. Will get on the needle tomorrow but thinking the rest will be spot on w/2nd clip from the top and 145 main. Then will be replacing the top end and taking my first shot at disassembling/cleaning the kips. Hoping the cylinder is in good shape

[bufftester]

Turning the idle screw in physically changes the position of the slide and opens up the throat letting in more air. More air being drawn in pulls more fuel. The idle circuit is the most important piece because it is involved in all the other circuits, so once you get it dialed you're through the really hard part.