You need to use a PCV valve! This place is full of posters asking the same question & complaints about chronic oil leaks from their engines. A breather may look cool but it is NOT a way to correctly evacuate combustion gasses from the crankcase. I know everyone thinks their engine's rings are good enough that they don't have any blow by, but they're wrong! Every engine has some amount of blow by & the gasses need to be removed by a negative pressure source. By manifold vacuum or otherwise. The breather is designed to allow air INTO the crankcase at a fixed rate. It cannot adequately vent the crankcase on its own even if you run 2 breathers. Failure to install a PCV valve or other form of crankcase evacuation system will result in seals & gaskets leaking, poor ring seal & condensation buiild up in the engine in places you dont want.
Do yourself a favor & install a PCV valve.