OK here are the needles for the 15-19.5mm PHBG carbs with their angles listed (which Dellorto failed to list). The needle taper is mostly for affecting the mid throttle jetting (rich/lean). Here is my site about carb jetting: http://www.dragonfly75.com/moto/carbjetting.html What I have found out by messing with my jetting calculator is that positioning the needle up or down has been erroneously suggested to do in order to correct the mid throttle jetting but I now know that the needle height needs to be mostly for when the needle taper kicks in to start letting more gas in. This page illustrates: http://www.dragonfly75.com/moto/NeedleHeight.html