On this carb - don't be afraid to go 2 to 2 1/4 turns out on air screw.
Make sure your idle is set properly and not coil bound... When switching from stock n1ef needle - *always* back out idle screw and reset it. This will have needle (and slide) down and bring low speed ckt (air screw and pilot) more into play.
If you air screw is having little effect when turning it in and out a half turn - something is off - need to dump stock needle - need to back out your idle and reset...
jeff
__________________
|