I don't mean to minimize whether or not you are having valid issues. But I don't believe using a caliper to measure across threads at an angle, caused by the fact that the caliper can't fit fully into the center of the needle valve at exactly 90 degrees is going to give you an accurate measurement.
ORIGINAL: Evgeny-arm
To Pete Bergstrom
I made that caused a shift Troubleshooting my needle carburetor.
Here's a photo of measurement.
I hope this information will be useful to you.
The last photo - outta size for photographing.
The correct size 1.41 mm