I am getting oil dripping out of the airbox when the XT is parked on its sidestand. I seem to remember from years ago the reason was a seal somewhere in the engine allowing oil to escape but it's been so long I don't really remember now. Can anyone give me a refresher? Thanks!

There's a hose from the crankcase into the airbox. Engine vacuum is used to prevent crankcase pressure from building up. If you have worn piston rings, the blow-by increases the crankcase pressure, which results in more oil into the airbox.

Some oil in the airbox is normal, enough that's its leaking says the rings are worn or its been a very long time since it's been cleaned, or it's taken a few dirt naps. There's a drain port on the bottom of the airbox. Does it smoke much when running?

I cleaned the airbox out last night, got about a tablespoon of oil out. I think I know the issue, I had forgotten that my nephew dropped it a few weeks ago on the left side, I bet it pumped some oil out the breather during that maneuver. I think I'll just keep an eye on it, and see what happens as well as check the hose while it's running to see if I'm getting much blowby.

Mine always has some oil in the bottom of the airbox. But that's because I don't wring the foam filter out well enough when I wash it and reoil it. It's excess oil in the filtering foam.