Have you done anything with the carbs recently? I thought I had some kind of ignition problem after I cleaned my carbs but it ended up being that one of the slides in my carb was stuck wide open. Try rolling your bike down a hill and kicking it in gear. If it runs fine after you do that I dont think its the carbs. It will probably be somthing in your ignition or magneto. If its bogging out in higher rpm check your carbs.