idle screw

When I start my bike it will idle very high and then rapidly go down to a normal idle speed. After about 1 minute it will start to decrease in idle speed and produces lots of smoke, it will continue to decrease until the engine has fully died. At first, I thought that I must be the idle screw...

My engine idles fine both after starting and when fully warmed up. However I have noticed that after using the throttle wide open (be it going fast or ascending a hill), if I pull in the clutch, the engine will idle very fast (to the point where I have to fiddle with the idle screw to slow it...

[B]If anyone has an idle screw and they want to help a guy out "sell it" that is can you let me know I cant find one any place there all sold out every place I look mine vibrated loose I'd fabricate one but I don't have the measurements of the original one