The one on the left with a visible spring is your idle speed screw.Screw it,more idle rpm and decrease by unscrewing it.the one on right is at an angle is the lo mixture screw allowing the engine to runs leaner(out) or richer (in ).You dont have to change needle if you change needle or the other way also,they both control midrange mixture.1972 T said:I have a Mikuni 34mm carb on a 440 f/c engine. heres a pic of it
View attachment 45575
looking at the front of the engine there is a screw on the right side and a screw on the left what should i set those at? Also when you change out the needle jet do you have to change the jet needle too?