CB1100 Idle speed instability problem

[dave]

Thanks Ferret and Max. Not a drop of oil trying to leak out of the valve cover. I used Yamabond gasket sealer, and reused the original gasket.
Guys, I have a minor glitch. I discovered that my fuel tank is not venting properly now. When I refilled the tank there was a vacuum sucking air in when I opened the filler cap. I stopped about 50 miles later, before entering the freeway, to see if my tank needed venting, and it did. When I got home I opened the filler cap and air was sucked in again. I lifted the rear of the fuel tank, and it was difficult to see if the vent hose was being pinched directly beneath the tank. So I disconnected the hose and blew through it easily, so I know it is not pinched anywhere between the fuel tank and where it exits out the bottom. I did my best to reinstall the vent hose to the bottom of the fuel tank and reattach the fuel tank without pinching the hose, but it's impossible to see the hose once you lower the tank into position. Is this rubber hose, attached to the bottom of the fuel tank, the only vent in the tank to prevent the vacuum I am experiencing, or does the fuel cap have a vent also?