Just a thought if you are talking about the crank end cover (right side of engine while sitting on bike) I found that I had over torqued the allen bolt at the bottom and cracked the cover because there is no support behind it leaving a hair line crack around the bolt land(boss)hard to see however once I new that was the problem I rewelded it and ground it flat and was careful not to over torque it and the leak was fixed.
maybe that is your leak?
