engine crankcase cover

My 79 XS650 has an oil leak on the right engine cover. There are some holes below the tachometer drive that have been filled with some sort of metal similar to sintered brass. Oil is seeping through here. Does anyone have a suggestion on how best to repair this?

Hey I have a very small crack in my Right crankcase where the tach gear enters. It seems the person who owned it befor me figured chroming the gases would be a great idea. The chrome shrunk the hole for that gear to fit and seems to have cracked the case right where the gasket seats. The crack...