Interesting...
I already suspected my dead carbs to be damaged by turning the mix screw in too tight... The exact size of this hole, and whether it had possibly cracked open a bit or not, was the only thing in the whole carb that I didn't check well enough to be sure.... And with both carbs the malfunctions were in the idle zone, they ran OK at WOT, but flaky at idle and picking up, and the mix screw had too little effect on idle rpm...
Your experience with the DR350 confirms my suspicion that I should be more careful when turning in the mix screw... And thinking back, I realise that this could also be the reason that it only occurred with Kymco carbs so far, because I never used this trick on any carb until I read about it in the Kymco manual (my previous bikes were all 2T and my cars never needed adjustment...)
Perhaps this is the source of a lot of other people's carb trouble as well ...