The gas needs to be completely drained before filling to achieve maximum fill. Lastly, recently I picked up a butane bleeding tool with a vent which actually works better than a screwdriver or pen. The thunderbird I believe is a different product made by Vector, a company whos lighters have given me endless problems. The pipe insert came in a hearth and home 'Fippo' if you will for less than the insert alone on sale from a fine store in Bethlehem, PA that will remain nameless. I have the soft flame pipe and single jet torch one as well. Works better than lighters many times the price.
I have a Z-plus insert as well which is awesome, it's my edc lately along w a little Tsuge Drew Estate gadget.
