man,
I am looking for the exact same part. I have the exact same carbs. I bought an old 77 CB750f, started rebuilding her, got to the carbs and couldn't figure out what the choke swing arm was for. took me forever just to figure out that it was the choke. anyways I bought a new choke cable and have it rigged up but I need that one piece to have it set up perfectly. If you ever figure it out message me, and If I ever figure it out I'll let you know.
-JJP