So, last night, I undertook taking the sticky out my concentric carb slide. Not having machinists' bluing, felt-tipped pen did well at showing the spots that rubbed. The 800-grit wet/dry paper (used wet) did a good job in three stages. Following the advice of one member, I used my vise to apply some backwards force on the flange, with the intent of reversing the bending that distorted the slide cylinder in the first place. This did seem to ease slide movement a bit, but I didn't have the cajones to apply much more force than I did, for fear of fracturing the flange.
Now, to the twist. When starting the reassembly of the carb, I went to look in the float bowl for any dirt. When I pulled out the float, the needle dropped out and, I thought, went to the floor. Not having a replacement I was at risk of having to wait for the post (and, maybe, spring) before I could ride again. This meant hands and knees, moving everything out from under the bench, whisk broom under the bench, all unsuccessful. Just before bed, hoping to eliminate one more possibility, I decided to sift (almost literally) through my trash can. Usually, no big deal, but this time there was about 2-1/2" of used oil-absorbent compound at the bottom. After removing the big stuff, mostly soiled paper towels, I went about inspecting the oily and rocky sand like a paleontologist searching for prehistoric mouse bones, about 1/4-cup at a time. Down to the last cup-and-a-half of the oily grit, OMG!, there it was. Damn, that thing is smaller than I remember from when I first rebuilt the carb. Unable to make a long story short at this point (or ever, maybe), I will just say, I slept well.
Richard L.