Oil in Air Box

[RoadTramp113]

Changed the stock aribox to a K&N intake. Opened the stock one and there was oil in the bottom, along with oil all along the tube to the FI intake.
Any ideas on what causes that and how to fix it?

[Mean Green]

Normal, that's why there is a foam filter in the stock airbox. Filter just needs to be cleaned along with the airbox. The hose that is hooked to the airbox comes off of the crankcase. With an intake now, no filter and the hose connected to the intake you are dumping oil into the intake. You need a catch can to stop this.