The Reed Valve Block serves as a connection between the Intake Manifold and the engine block to control the intake process.

The Reed Valve Block controls the intake process: When the piston moves upward, a vacuum is created in the crankcase, the Reed Valve Petals open, and the fuel-oil mixture flows in. When the piston moves downward, positive pressure builds up; the mixture is pre-compressed, and the Reed Valve Petals close, preventing backflow. Thanks to its flow-optimized passage, a racing diaphragm block is a staple of engine tuning.