The first two I filled, I was getting a slight burnt taste with one, and the other was fine, right out of the box, with no modding or adjusting. The one that was tasting burnt, I had used one of my Ming vase drip tips. The other one, I used the one that comes with the Fluxos. I took both tips out, and looking at them closely, I noticed that the shank on the Ming tip is just slightly longer than the shank on the one that came with the Fluxos. Consequently, the Ming tip was pushing the silicone cup seal down just enough to contact the coil, on the underside. I trimmed off the bottom of the cup seal where it had burnt, reinstalled, and when putting the drip tip back in, I didn't push it in as far. Just far enough to touch the top of the cup seal, which leaves maybe 1/32 inch space between the shoulder of the Ming tip and the top of the tube. Now it vapes perfectly.