Seating adjustable fuel needle

So, I removed the stock screw(had to drop the float bowl, couldn't coax stock needle out), and now the new one is not threading in easily. I figured I better check here before I try to just jam it in.....

The shaft below the threads of the new adj. needle is bigger than the stock needle. Is this normal? The bike is an 02 ktm 400sx. Pkg(system tech racing, 70-02)says ktm 250-530, but not year. Pretty sure it's the stock fcr carb.

Any ideas?

I bought a replacement fuel screw for one of my bikes once, the kind with the knurled knob so you can get some fingers on it. It was the proper screw, its just that thread friction was very high making it almost impossible to turn, to the point of seizing.

Thread pitch was right. Comparing the new screw with the stock screw revealed shallower threads in the original screw. So that meant thread peak on the new screw was too high.

I took some fine emery cloth and rolled the new screw threads between my fingers/cloth, periodically checking fit until I could screw it into the bore all the way to the seated position with just my fingers.

If you try this, make sure the bore threads are clean to begin with and before trying to fit of the new screw between attempts, make sure you use an old toothbrush or something to clean the threads of the screw.

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