first thing check to see if the oil has a gass smell if it does change the oil and clean the carb if gass got in the oil after you change the oil it will still smoke for a while but it will quit.
bubbafw
June 2010
1 have you tip it over to clean it
2 is there too much oil in it
3 it may be the oil ring's
if you have tip it over to clean it it will come out of the exaust, is it water cooled that will also give you the white smoke, or water in the fuel
take off the head and have a look see if the gasket ok then have a look at the ring's.