That gauge action is normal for any engine, going from the video. That's a significant change in engine speed and not, IMO, what you have led us all to think was the issue. It's nothing to do with dipping the clutch but everything to do with a significant change in engine speed. What did you think would happen? And that doesn't look like a mechanical gauge but a standard one. I'm guessing your mechanical knowledge is, let's say, limited?