old indian trick I learned when I was a biker - once tried to 'drain a little oil' after I slightly over filled after an oil change. Oil comes out with some bloody force and I struggled to get the sump plug back in quick enough and made a right mess. If you can get a plastic syringe and some tubing, draw the oil out through the filler if possible. Obviously a lot easier on a shallow motorcycle engine but worth a try. From what I remember, over filled oil can cause a bit of damage to the catalytic convertor or might end up with oil in engine box - can't remember where I've read either of these things but they spring to mind...