Just picked up an
hcigar kayfun 3.1 and I see why everyone fills them from the top. Well, determined to use that fill port I broke out the magnifiers and lights to see why it doesn't work. And I found it.... on mine at least. First problem, when the holes are cut in this they resemble the letter L. One leg of the L is exposed inside on the deck and the other receiver a spring, steel ball and cap (making up the check valve). The problem here is then the cap is pushed in, it peals away metal behind it. These fragments get stuck and prevent the ball from fully opening. So, they must be cleaned away with a pick and pressurized water, leading to the second problem.... your needle. A standard blunt tip will not work well. When the blunt tip contacts the ball inside it acts like a flat surface and all but plugs the tip. Take a purple 16Gauge gauge blunt tip and sand down 2 sides a bit. Now, take this modified needle and a syringe, fill with water and use it to pressurize the water through the check valve. You will need to do this under running water and push and pull water through the valve while also using a piece of wire from the top deck area hole breaking up the "chunks" of metal. Took me about 5 minutes to clear it all out, but you wouldn't believe how much metal came out. If you can't use the valve on yours, I would suggest trying this even if you don't want to use it.....only reason I say this is because I'm not sure if that metal inside can rust or become dislodged over time, and could be the reason many have said their valve leaks. After doing this, I can take 4 mil of
juice in a syringe and just push it through fast with absolutely no leaking.
The mounting screws on the mini are so tiny, Any advice on what size Kanthal I should use with the mini Kayfun? 
