Smoke and oil from the exhaust

Just finish cleaning the carb on my B/S mod 40m777. It had been setting up for about two years. Carb cleaning went very well. Put it all back together, fired up just great but all of a sudden I've got a cloud of white smoke all over and a good bit of oil is being spewed out of exhaust. I shut it down to see if I can find the problem. Oil left in crankcase is clean but the oil being spewed out is totally black.
Any clues as where to start. I can go as far as an overhaul if necessary. But it...

Smoke and oil from the exhaust