You can run a bolt in place of the original allen head screw. You just have to modify the end a little to make it seal if you ever want to close it completely. Run the pipe and check it by splashing water on the chamber after a short WOT run. If the water sizzles heavily then the chamber is too hot and will probably melt couplers and hoses. A popular setting is about 1/4 turn out on the bottom screw and then adjust the top screw out until you get it the right temp. I run mine so that it will just lightly sizzle after a short WOT run. I do this because I rarely do WOT and this lets me keep the chamber temp up for better response during freestyle riding.