.
The issue isn't that the o-ring is missing, the (potential) problem is the chimney not fully contacting and seating into the top cap o-ring correctly. I added an extra o-ring between the base part of the chimney and the top part of the chimney, effectively increasing the height of the chimney by a millimeter, providing a better contact.
I'm up to seven different KFL and KF3.1 clones now. I found the needed o-ring in the spares from one of the others.
my KFL's have that problem... it doesn't quite fit right. What I did find, that was very useful, is a small piece of aluminum that is the same diameter as the top of the chimney. I stick that through the top cap and use it as a guide to guide it on the chimney as I screw it down. it works flawlessly. I believe that most people with their kayfun's leaking or gurgling have the o ring not seating properly.



I needed you Laylel 

.. Seriously, all of your set ups here in the photo look very sexy, and very well put together ... Ms. Nikki approves. 