Re: how bad is this?
Any time you detonate the motor it tends to eat parts . You probably have a hole in a piston or two that is causing a lot of crankcase pressure . This is the reason for the oil in the air cleaner . You need a new motor . Nothing will fix it , not even the extractors that are mentioned in a reply from Mr. Goodwrench below . Go ahead and buy them . Then you will be out the money on the extractors and the time spent installing them and be pissed that they do not work plus your motor is eating more oil than gas . New motor .