Are you sure that smoke wasn't coming from unburnt oil leftover in the muffler from before you rebuilt the engine ?
It can take 5 to 10 minutes to burn out an oily muffler..
Did you deglaze the cylinder ?...stagger the rings?...check the reed valve ?...
If You Have All The Answers...Except The One You Need...You're Not Trying Hard Enough...
Do The Work