How to do the slide modification to the XR650L carb. 1)Rotate or remove the carb so you can remove the top cover from the carb. 2)Remove (gently) the rubber surround and the slide from the carb body. (The needle will come out with it. 3)Remove the needle, by turning the phillips head screw 1/4 turn so the needle comes free from the slide. 4)Drill out the bottom two holes, (NOT the third hole where the needle goes through) and clean up any metal shavings afterward. 5)Install washer below needle head and re-install needle. 6)Install modified needle/slide into carb body, and put carb top back on. NOTE: (sea-level jetting ONLY) Turn fuel screw 2 3/4 to 3 turns out. Install 165 main jet (bottom of carb). Remove airbox snorkle and exhaust plug.