I have a low end to midrange bog i can not cure. Bike is 2002 300ex with FMF exhaust, port & polish, titanium valve springs, big cam. I am using the stock carb, and the thing starts up and idles great. As soon as i start to let out the clutch the thing starts bogging and spitting and sputtering until it climbs to the upper RPM's and then it runs great. Is this a jetting issue or does it sound like something else. I even switched carbs and it ran better but still had a pretty decent stumble revving up. Also, it seemed to get worse as the motor got hot. Any help is greatly appreciated.