hello i have a 1976 honda cb550 with 750 carbs on it. it had 120 size jets in and the plugs were black and sooty with the air mixture screw all the way in. i put in 95's and the plugs still black and sooty after replacing them and mixture screw all the way screwed in as well. so today i put in 87.5 jets and the same thing is going on ....PLEASE HELP ME!! i just want to ride...also when the mixture screws are all the way in is that leaned out?