I tried inserting the pinch bolt through the exit hole and inserting a penny into the slot. Maybe they don't make pennies like they used to.
I removed the penny and tried a steel washer. It worked better. That said, those Profile Stoker bars are not interested in going through that stem. I don't have a caliper but will get one for future use. It's a moot point for the bars because, whatever the size of the bar hole in the stem, the bars are not going all the way through there. I put my trusty Staedtler circle template on the stem extension tube. It's 28.6mm. So, it looks like any standard stem with 31.8mm bars and 28.6 tube should work, right? I am looking at
https://www.amazon.com/FOMTOR-Mounta...g%2C121&sr=1-5.
Shouldn't that work?