I was passing a car today and got on it a little, about 5300 RPM's. Bike started loosing RPM's like it had run out of gas. I look behind me and it's leaving a trail of white smoke. Never lost any oil pressure. I let off and pulled over. looked it over and found nothing visualy wrong. Started it back up and rode 15 more miles with no issues.

Any ideas of what's going on?

 

Sounds like sumping from an oil pump issue, namely the scavange g rotor. Due to the Heavy Breathers engine breather's curcuit it will pump oil into the engines throttle body and burn it, rather than say the stock system that will drip all over the place. This is one of the reasons I like this breather, but it won't give normal indications of oil carry over like the stock unit should you develop a problem like this.
Ron

 

+1 on oil carryover. Could be sumping, but I would start first to ensure the oil is not overfull, in fact a lot of HDs will push oil through the breather unless the oil is showing about a half a quart low. Don't ask me why, but it has fixed a lot of bikes that had carry over throughthe head breathers.