idle hangs with lighter slide return spring.

[stainlesscycle]

i've not figured out why this is happening. i ran the heavier spring and it worked fine for last 3 months, but i was sick of the right arm pump i was getting from having the draggy throttle. i've had this lighter spring on in the past and it did the same thing i am describing here.

i switched to the light spring, and throttle opens so smooth and easy, and i can get into the meat of the power without gripping tighter. it's 1000* better, and i can ride faster with less fatigue.

BUT idle wants to hang, and it kinda drags me along a bit. i've lubed and slackened the cable, played with idle and air screw (even adjusted the idle screw way out, so it was definitely closing), even tried another light spring, that i stretched. nothing works. is the lighter spring just not slamming the slide down with enough force to 'keep it shut'? i can hear it hitting the idle screw. i'm assuming that when i'm coming from wot, that the velocity of the mixture is burbling the slide up off the stop?????? or the velocity of the air is stopping it from settling down? the slide is smooth, with no nicks or burrs, as is the slide bore. or am i just imperceptibly leaning on the throttle enough to barely lift the slide??? i thought that was the case, and added a bunch of slack in the cable, but that did not fix it.

it's just a goofy thing, but it drives me nuts. i'd like it idle down asap, just like the heavier spring does.. i can fan the clutch a tiny bit to drag the motor back down to idle faster, but that takes concentration on something i'd rather not focus on. any solution??