Smoky

Ok, My 2013 rancher 420 started smoking from muffler, white to gray smoke. Pulled plug and it's black and a bit wet, that leads me to believe a gasket or rings shot. No oil in muffler, with muffler removed, it barely smokes but still does. Oil and coolant levels remain the same. What could the issue be?maybe valve gasket? The muffler was loose where it meets the heat shield and I rode through water 2 rides ago. Any help very much appreciated.