Yes,you need to remove the plastic stopper and there is a set screw and you can remove the needle ,when you shim it make sure your shim outside dia is not larger than the outside dia of the top of the needle where it sits on top of the slide or it will not drop down all the way into the slide causing a very rich condition,also do not over tighten the set screw,tighten just enough to touch and hold,a very thin shim will make a diff I used a 20 thou one in mine ,I have white brothers pipe with a suppertrapp end using two disks 180 main and one size larger on the pilot jet ,no air box and a uni foam filter ,pulls well all the way thru the rpm range no flat spots
