FXR oil tanks can be confusing as to hooking the oil lines up correctly. I don’t ever remember seeing the hose bungs marked, and if they are marked they are impossible to see. The vent and return lines can be switched around without concern, as far as I know, because they are both connected to tubes that go to the top of the oil tank. The feed line of any oil tank will always be the one that oil flows from, because they must be on the bottom of the tank, or very bad things can happen.
Below are the connections to the engine and oil pump. The feed line is almost always on the outside of the pump and I believe marked with a small “F” for feed, from the factory, and S&S oil pumps I believe are marked with a “S” for suction.
Not shown is the oil lines for the oil filter. There are different oil filter configurations as far as mounts go. You will have to figure out the correct line hook up for your bike. The oil ALWAYS Flows from the outside of the filter to the inside of the filter. Below is a diagram of how oil flows through filters. What ever hose nipple goes to the CENTER of the oil filter, gets connected to the oil tank
