I have a 72FLH stock 74cuin.I put a new set of jugs and rings about 2000 miles back and I have started seeing a little smoke from the back cilender about a week ago,not a lot just enough to notice.never on startup only after the bike has ran about 15 minuites and when I turn off the engine a stream of smoke will drift out the pipe.so I pulled the plugs and they look great,nice lite gray and compression check is 90 psi in both so I pulled of the exhaust and took a look at the exhaust valve and I could see a little oil around the stem and guide and the rest of the valve that I could see was very lite gray.I did not do any work to the heads ,valves or guides when I changed the jugs and rings......thoughts....thanks.

 

My guess is you already know whats going on, the valve seal and or the guide is worn out, over the years we see many tin seals self destruct and that only makes the guide and valve wear quicker.

the blue rubber seals are a better deal all around -- johnjzjz

 

yeah I think its a guide...I should of just had the heads done but live and learn.i will take them off this weekend for a look..thanks

 

Drop the rear pipe and look up in the port with a mirror , the valves wet it's the guide , the guide itself is wet the guide's working loose in the head and oil is getting past when she warms up . Common on the older ones . Rear head on a shovel gets too much oil anyway and the rear exhaust is the low point so ....................