Guyz, this is monumental. Youse could be on the cusp of uncovering the anomaly that has been plaguing untold numbers of bikes with linked carbs that have idle problems...
I'd call this typical for "most of" the BS38's I have.
View attachment 102373
I would expect this carb to run an engine with no issues.
...jb weld? Get original formula not the more commonly seen fast set.
...What about a wave washer for a RH spacer?