I know what a mixture of oil and water make. I learned it a long time ago when the block cracked on my 1970 Camaro. I too have seen the stuff excreet from my vent line. I do know it is common. Why though? I initially thought head gasket leak. The engine oil is still a pretty black with little shiny specs...oops, that was my neighbors YZ250 stroke after it seized. Anyone know the exact reason...Clark or James? ------------------ '99 WZ with all YZ mods, FMF PowerBomb header, Stroker SX-1 silencer, SS front brake line, forked over by Pro-Action, OEM YZ tank and IMS seat.