It sounds like your engine wet sumped. Basically, if you leave your piston at the bottom of the cylinder when you park it, it will fill up with oil causing massive smoke on start up and eventually clearing out over a few minutes. To avoid this, make sure to move your piston to TDC with the kick starter after you have shut the bike down for the day, or if it's going to be sitting more than a few hours. To do this, very slowly bring the piston up with the kick starter until it starts to build compression, move it just a little bit further and you should be good to go.
Scottie