I had a similar issue (with my own '79 CB750 LTD) - Chatted with the guy that did my restoration and he replied with the following...
"From what it sounds like in your video, the small air passages to the cold start jets may be stopped up, possibly from the time in transit to you. These passages are very tiny and if any fuel stands in them for long, it clogs them just enough to create an issue like this."
When I spoke to him later on the phone, he was suggesting a small piano wire to clear those jets.
Not sure if that clears it up for you, but I suspect it is what I will need to do as well since I have not had the bike running since I spoke with him.
