FIRST POST Idle mixture screw tap

My bs34 carbs had a stuck and stripped idle mixture screw. I managed to drill it out enough for the tip to pop out without ruining the carb. Now I’m left with a thin wall of brass covering the threads. I was thinking I would run a tap through it to clean out the brass, but I’m not sure what tap to use. The threads are so fine. Does anyone know what size tap could accomplish this or even another method?

You can but be careful and don't just jam the tap thru the left-over brass!! Take a half a turn, back-out, blow it out, repeat. Tap size is M6 X 0.5. Have FuN. I do them all the time, ain't that hard but be conscientious about what you are doing!!  

Here's a sample photo to guide you. Noteworthy though, you must to of just "kissed" the existing casting threads for this to work. Too much left over brass and you'll be fighting it.   

20170527_134643 by nessism , on Flickr

That brass insert is waaay cool but doubt anyone could duplicate that, ha. Kudos for You my Friend for even broaching that!!

Before attempting to tap out the passage, you must use a drill press or milling machine, and make sure your tap is centered above the passage.  I used a pointed tool, chucked into the drill press, lowered slowly, to make sure it was dead center into the passage.  There is a tiny hole in the bottom of the passage.  Make sure your pointy alignment tool is dead center aligned with the carb body hole.  Then remove your guide tool, install the tap, and feed very slowly while turning the chuck by hand.