Thank you Jerry for the very detailed explanation. And Q2W, I assumed that the slide stop screw was the idle adjustment screw like it is on my keihin carbs. I am not used to dealing with mikuni carbs. All my other 2 stroke quads have keihin carbs on them. So the needle jet is a new one for me. I checked it and it has a R-4 in it. Next time I get into the local dealer I will pick up a R-6 and try it out. Also it sounds like this is normal to a certain extent. So I am ok with it. Wont be able to mess with it too much this week anymore. So when letting off the throttle at higher engine RPM's like decelerating in 5th gear, is it easier on the engine or more desirable for the motor to not fire when coasting? Right now it is just like hitting the kill switch until you pull in the clutch. I think before I could hear the engine still firing in the pipe. I just want what will make the motor live as long as possible. Thanks.. AND after tinkering around with this mikuni, I think I might try one on one of my hondas. Looks like keihin carb jetting for the zilla is pretty similar to what I have in my hondas.........