changed the oil on my 2011 900 custom, over filled the crank case, drained oil to the proper level now I have a slight leak. it is either coming from the head cover gasket or from the plug that is in the middle of the jug just under the head cover, the plug is about the size of a quarter. looking at a diagram it shows that this plug has an o ring on it . has anyone had a problem with these plugs leaking oil? if so how do you remove the plug to replace the o ring?