08-10-11, 10:43 PM
it might be valve clearances issue. i think tight valve clearances can cause a lumpy idle. at 40,000 they might be out of spec. turning the mixture screw a few turns is probably not a great idea. i think they are fairly sensitive to adjustment. you should be trying 1/4 or 1/2 turn adjustments not a few turns. it might be worth going back to the factory setting and trying again. have you check your plugs since adjusting the carbs? they should be a brownish colour around the electrode