Practice , I'v found that there is a certain order to my 640ADV . Some times it involves removing unrelated parts to the job at hand before I service the part I'm after . For the main jets of my carb. I would remove the carb. altogether . This would give me chance to clean and inspect it thoroughly . For me this will go in this order , seat , sceen , tank , all hoses and wires to the carb. , remove nuts and bolts to boot clamps and then twist carb. and take it up between the rails of subframe (I do not undo the suframe ) . All parts are cleaned including hoses , vent tubes , cable contectors (I had a elec. problem are atrip to speed week I mist a plug and the dust and salt broke the conection cleaned it problem solved ) . Putting the carb. back will be the revers . Every job I do any part removed is cleaned in parts washer (best money ever spent ) before going back on . At home any contoction opened is cleaned with contact cleaner . I mite be over the top but on the track the few problems are solved quickly and easily . I'm not sure if this will help but the first few time were a night mare for me too it's much easier now thow , practice.