Looking for a little help here. I purchased a 2002 GS 500 a couple of weeks ago and have noticed since running a couple of tanks of gas through it that it has a pretty noticable "miss" to it under 4000rpm. It is really noticable when starting out in first gear, it will sometimes cut out just as you are taking off. While warming up it will back fire here and there and while revving it up. The bike sat for some period of time as it only has 1900 miles on it. The guy I bought it from said he had a "friend" go through it and drain the fuel and replace hoses and clean carbs and petcock. He only had the bike for 2 weeks before offloading it to me. I know red flag but I was thinking its a GS how can I go wrong? I know usually they are pretty bullet proof engines. Does anyone have any input? My bike mechanic guy tells me they have vaccuum carbs and literally suck that I should think of taking them out and using a different type. I forget what exactly he recommended but I just thought I would ask. I have read here about how they come set up lean from the factory and can tell mine looks that from the whitish tan on the plugs. Would love some input. Thanks