Motorcycle Repair: Suzuki GSF 1200 Bandit, suzuki gsf 1200, suzuki gsf 1200 bandit

Question
I own a 7 year old bandit with 11000 miles, well serviced and looked after.The bike is garaged all winter.It starts  first time and idles no problem pull away and between 2000 and 4000 revs it back fires and there is a lack of power wind it open and its off like a missile roll the power off and it below 4000 revs it cuts out occasionally but sounds really ruff. New plugs,air filter ht leads valve clearance and carbs synchronized still the same. I drain carbs if bike is not being used for 2/3 weeks. Please help its driving me nuts.

Answer
Even though you are draining the cards the ports probably still have varnish in them. More than likely the pilot jet circuit as that is the 2 - 4k range and the other jets build off that. Your going to have to completely disassemble them and put them in a "carb dip" (NOT JUST SPRAYING THEM OUT WITH CARB CLEAN!!) this will get the gunk out of the ports. Follow up with me if you need more info on doing this...