A few facts about needles..
Needles are tapered shafts screwed into holes in a carb..
Modern machining methods are very precise, however----A carb body is a casting, and not exactly the same every time.
The needle is threaded, and there is no guarantee the threads will start, relative to the taper , on every needle...
The little hole that the taper fits into is drilled into the casting at the end of a threaded hole ..There is no way to start the threads exactly the same on each carb casting...
There is no exact way to determine the position of the needle, your 1/8 turn may not be the same as my 1/8 turn..THERE IS NO POSSIBLE WAY TO TELL THAT 1 TURN OPEN IS THE CORRECT SETTING..LEARN TO ADJUST YOUR OWN CARB NEEDLES, DON'T RELY ON THE "FACTORY" SETTING, IT CAN NOT POSSIBLY PREDICT HOW YOUR ENGINE WILL BE USED..[8D]