Alright guys, I’m totally new to the carbs on these. I have just left them stock for as long as I have had the bike, just did a deep cleaning and new gaskets. I have done a ton of reading, however I have not found much on the screw with a question mark. Pretty sure the a/f mixture screw is on the bottom, then the idle adjustment is labeled in the pic. But what is this other screw?? I know that on a lot of carbs, air screw is typically on intake side, then fuel screw is on the engine side, but it doesn’t look like these carbs are made like that. I would also like to note, that the “?” screw is turned all the way in… first time touching it. 1978 Cb750k will run but cuts off if I don’t have the throttle pulled a little, has stock air box, and chopped exhaust. I know I’ll have to upgrade jets but just want to know exactly what screws I’m working with here. Let me know if you can give any advice!