Did you recently change the oil? If so, maybe you overfilled a little bit. From other discussions here, most folks, including me, found that filling the crank case to the indicated "full" level will cause some oil to be routed through the breather tubes and into the intake/air cleaner. As the oil level goes down, less oil will come through.
On my '12 Street Glide, I had the same a problem. I found putting in a little less oil at changes helped, but I had to keep a close eye on the oil levels. That bike burned through at least a quart every thousand miles since it was new. I think HD's bikes vary a lot in quality. My '13 Ultra only uses about 1/2 qt per 5000 miles.
If using less oil doesn't help, venting the oil like r0de_runr did is another option. I think Harley should have done this to begin with, but I'm sure it would have really dug into their profits...
