Have you messed with the carb lately or throttle cable? If the slide is not seating all the way in the carb it will trip the TPS and cut off spark. I took my TPS off not knowing that I shouldnt when I cleaned my carb and let me tell you, I sure wish I didnt. My bike is all screwed up now. But anyways dont know if this will help you but just thought I would throw it out there.