I need to look at a demon carb.... now you have my interest... LOL. I'm betting the design of the door is molded to start the syphoning of the back barrels. That's why the eddys and TQ's have funky shaped air doors. Vacuum pulls the door open, but the door design in pulling fuel rapidly. Maybe I'm just too old school and I can't leave the TQ design. Maybe the Demon is completely different. I just can't imagine it working differently.