Ok, so I am not new to working on motorcycles, however, I am new to the CB 750's. I recently aquired a bone stock 1980 CB750F Super Sport with Keihin carbs. The carbs needed cleaned. After cleaning and reinstillation I drew a blank as to where one of the tubes hooks up. Just to the right of the fuel rail is a tube approx 1/4" in dia that I cant remember where it goes. According to the manual, I believe this is an air rail? It would appear that this tube runs along the top of the air cleaner box and just vents to atmosphere. Oh smart cb'ers out there, please impart your knowledge on me.
My wife said if I buy one more toy she was going to leave me......I'm going to miss that girl!!
If I'm visualizing this correctly, this is a breather tube for the carb bowls. There are two holes on the ceiling of all those carb bowls and if they're clear, you can feel air escaping through the ones in #2 and #3 if you blow into the rubber tube that connects to the rail. The #1 and #4 bowls each vent into the #2 and #3 bowls, respectively, and from there through the tube.