Or just blow air through the reg gauge hole. Idk if that tool will damage the fx reg piston. Since it's made of plastic. Even plastic on plastic, it could scratch the piston and cause reg creep.
I use a piece of rubber fuel line that I picked up at a hobby shop. Works great. Also, if getting the piston out is stubborn, I just use a small syringe to blow it out with the air gauge removed.
Great thread! I'm planning to swap out my AMP reg and install my Huma this evening. If I'm comprehending the piston removal process correctly, the soft plastic pen tube will grab on to the piston to pull it out, right? If so, does anyone know how much larger the pen tube's inside diameter is vs. the piston? I don't necessarily need the measurements - wondering if the fit is pretty snug or not