<VV> Oil in Muffler

[John Ingram]

I toped off the engine oil the other day and slightly over filled it  
(65 110).  I later discovered that the extra oil had found its way  
into the right muffler and made much smoke out of the pipe as it  
burned off.  My question is: how did the oil get inside the right  
exhaust pipe and muffler?
Thank you to all who replied to my leaking carb connections  
question.  I retightened the carb tops and lines adding some silicone  
to one connection.  No more leak.
John Ingram