Like a jackass, I let my 2000 XZ426 sit for the past 6-8 months with same gas in tank. It usually starts with less than 5 kicks (cold or not). But it did not want to start this weekend. It finally started w/choke but would not idle without choke on. I'm prayin it's only bad fuel. Is there a carb cleaner/treatment I can or should pour in the take to make sure carb is clean and working properly. If it's something more serious like needing a valve job or valve adjustmeny, what should that cost me?