If you let the gas sit for two months in the banshee you run into the oil and fuel seperating and if you had fuel in your carbs i could only assume that it seperated in there and if it were me i would pull fuel bowls off spray it with some carb clean and get some NGk's personal prefrence on those. I have never changed a NGk due fouling just changed cause of it being old, used, or just felt like it needed a fresh plug real good plug if you ask me..... i belive NGK Makes an iridium plug as well it should burn a little hotter... you get what you pay for when you buy plugs