Travis, remove the exhaust system from your motor. Manifold also. Hit the green button. The motor will crank, the plugs will spark, the fuel mixture will ignite, the front piston will go down, the rear will come up, the process will start all over again. Oh, for the record, when the piston is on its up stroke, it will suck the fuel air charge into the cases, when the down stroke occurs, the charge will then be forced up through the intake ports in to the chamber, the piston will be coming back up. Charge gets compressed. Pow, ignition. Process starts all over again.
Guess what, the pipe is not on the motor. The motor is still running. You had one thing correct, the expansion chamber controls the sonic wave which in turns gives the motor its tuning characteristics.