Carbs

Hey all, I have a 1996 750 Virago. It had been sitting for a long time before I bought it. It idles fine, but nothing above that. I've tried every carb cleaner known and no luck. I began to remove the carbs according to the manual and removing them is near impossible because of the mounting studs. Does anyone know of a technique to remove them? One Yamaha tech said he always removed the studs. I find it hard to believe that..He may be right..Thanks for any help...