My 1100GS has had some crust around the two lines that exit the block on the upper RH side. After a recent oil change it now leaks just enough to leave a few drips on my pants after a long ride. I ride this bike to work, so that's unacceptable. I see in quite a few threads where this is mentioned as a common leak, but I haven't found any articles or threads actually showing a fix. Are the O-rings a commonly available size, and is it a difficult job? Any pitfalls?