Carb Tuning with AFR Guage

Main air bleeds work harder at high rpm. They will not lean out the bottom end without effecting the top end even more so.First you must get the fuel curve flat. Say 11-1 All the way thru the rpm range. Then lean it out to what you want. Smaller bleeds is what you want. They will make the bottom a bit richer and the top even more richer. More than the bottom. Making your fuel curve flatter. Keep going til the curve is flat. Then lean out the main jets. You can lean out the mains at the same time so as not to foul your plugs out.