Hi. I have a 2001 katana 750 that I purchased recently. It sat for a few months before I started it. It took forever for the bike to get running. I took the carbs off, tore them apart and cleaned everything. All the jets are clean and the a/f mixture screws still have the factory plugs. The bike runs now but is hard to start. Once started you have to constantly mess with the idle screw. Sometimes it idles at 1000 and sometimes 2000. Everything leads me to believe the air fuel mixture is not adjusted correctly, but they´re still adjusted from the factory. There is nothing aftermarket on the bike and the fuel and air filters are new.