Vintage BMW Motorcycle Owners

Nice sleuthing, Michael-
The hole you've put the wire in is the idle circuit air intake passage.
That passage is where air is pulled through to the idle jet, located behind the slide.

Was that extra hole in the slide floor there all the time, or only after the vinegar soak?
Anyway, you'll want to be careful your patch job does not obstruct free air flow through that passage back to the idle jet.

That's the thing, it's a little hard for me to know when the hole occurred. It was there before the vinegar soaking, I'm sure of that. It should not be forgotten that the bike stood for several years with a fuel system that was not drained or cleaned.
Anyway, I finally decided to try with an engine sealant paste to try and close the hole, then continue looking for problems as the guys detailed to me here in the previous thread. I just had it new in its packaging (the quicksteel stuff should first be purchased). I scratched the area well with a screwdriver's tip, then used some fine emery paper, cleaned all well with acetone and went for it. Hopefully I will find time to install the carb on the R51.

I do not understand why the order of uploading the photos came out the opposite, but you will already understand on your own that the order of the photos should be the bottom up ...