after and adventure build on my drz440E , my bike slightly surges in power during a constant speed. not during acceleration at all. My bike had a 165 main jet and i swapped it for a 155 main jet. it runs better now but it still does it. many people say this is what happens when the bike runs lean but my spark plug is black, i think it is running too rich. when my bike is warmed up and idleing, i can turn my fuel screw all the way in and the bike still idles and will rev. This, as i understand it, means i have too rich a pilot jet. The odd thing is, the engine/ exhaust is stock except i opened up my air box, which if anything, would make my bike run lean. before i buy a smaller pilot jet, could anything else affect this? timing? anything? i know the carb has three jets, could it be the mid jet (name?)? should i lower my needle (raise the clip) one notch to see if it helps? i have the JD kit with blue needle on third clip from top. FCR carb. 0-200 ft elevation on average, 90degrees F in summer and 45-60degrees F in winter.