Once the bike warms up, and you turn the choke off does it idle fine? While this may sound off, it's true, you may be rich on the bottom end, and to make it idle you have turned in your idle screw forcing the slide up. The slide is now in a position that allows the bike to idle right for normal conditions but because it is touch lean for the slide position when cold.
Now mind you I'm assuming that when its warmed it idles fine, if so then look at my synopsis, if it idles high all the time with the choke off, you have an air leak or carb issue.