i have a 98 banshee with exhaust, trinity single carb, and a cool head. i was riding this weekend and it started acting up. it wont idle without giving it gas and runs rough at lower rpms. Seems like the left cylinder is misfiring the right seems to be fine. When you give it more gas, it revs higher and runs great. i switched the plugs and it still did it. I also took the reed valves and checked them but they seem fine. any ideas on what it could be?