RUN - Don't walk - away from this one!!!!!!!
I can't stress enough that if you buy this bike, it will be nothing but problems.
Four strokes - especially XR's - run FOREVER with all sorts of stuff wrong with them. You can abuse them, run 'em out of oil, over heat them, over rev them. While you're doing this, damage is happening inside that engine, but the bike just keeps chugging along.
Any time a four stroke breaks down, it's not just ONE thing that caused it to fail, but all those horrible things finally catching up with it.
If you fix the one thing that is obvious, then put the bike back together, all the other stuff will come back to haunt you. It's frustrating, it's expensive, and it could be avoided.
NEVER buy a four stroke that has had overheating or oil delivery problems unless you're a mechanic and you know what you're in for.
I don't care how cheap this bike is, it'll cost you in the end.