Its your balance shaft seal. If it was the crank seal your motor probably would have lock up by now.also running it 50 to 1 is going to make it super rich. Less oil means more gas going threw the jets. Should run 32 to 1  and that might help lean the jets back.  Because gas and oil go threw the jet at the same time.  But then it gets compressed by the crank as the fuel gos up to the port the oil separated in air and falls back down to the crank. Then the crank slings the oil for lubrication.
But they say for every 4 ounces of oil out drop one main jet. What are your jet sizes  you  are running