I have had this bike for about a year and a half it ran fine until summer started and then everytime i snapped or rolled on the throttle just a little it wants to bogg or shut off. It works fine if i roll on the throttle real slow but when i twist the throttle to fast it boggs out. I know for sure the problem is not my valves because i have had it in the shop 5 times in the past couple months. My guess is, is that it is the carburator. I have a big gun exhaust on it and Z&M cycles tell me to keep it at stock jetting, but big gun exhaust tells me i should run a 178 main jet and a stock pilot. I dont know what to do If anyone can tell please HELP ME i havent been able to race or fully ride all summer this is my first four stroke and so far i dont like it due to this problem.