In fighting with oil problems, I was tracing out my oil lines just because they were there. Staring at the side of the oil tank from the starboard side of the tank, my manual shows the left most line as the main oil feed (actually separated from the other two) and then the middle as the vent and the right most as the return from filter.

On the bike, the vent and return appear to be switched. If I remember correctly, both of these lines just end up high in the tank.

Does it matter if these lines are crossed? If so, how do I tell which is correct?

 

The oil lines on my bike (95 FLSTC) match what you said your manual shows. While I don't know if having them crossed matters I know they work well in the manual configuration. It is easy enough to change them if you want.

 

I recall someone on here recently purchasing a bike very cheap, then having a lot of oil related problems. His lines were crossed.

If I was you, I would change them to match the shop manual exactly, if they are not that way now.