When an engine is running at full throttle, a large volume of burned gases flow through the exhaust. Part of the gases are expelled out of the exhaust pipe and part of the gases find their way towards the fuel tank.
Engines have 2 main settings, High Speed Needle HSN and Low Speed Needle LSN. Engines are tuned to have the highest speed possible with the HSN and to be stable at idling with the LSN.
When the engine stands idling, only a small amount of pressure is created, when the engine runs a full throttle a large amount of pressure is created.
Problems arise when you switch from full throttle to low speed, high pressure generated from running at full throttle is still present and it is pushing fuel to the carbutaror inlet though the carburator is closed. Because of this the mixture will become too rich, causing slower acceleration and wasting fuel.
The CRF CPD acting as a pressure valve system, effectively resolves this problem by regulating the amount of pressure going to the fuel tank. The valve allows a constant amount of pressure to be sent to the fuel tank, by opening or closing itself depending on the engineâ€™s rotation speed.
Constant pressure allows for:
â€¢ Easier adjustement for ANY type and size of engine.
â€¢ Better low end response because the mixture always remainscorrect and does not enrichen because of the excess pressure.
â€¢ Longer run times because there is no excess pressure pushing un-needed fuel inside the engine..
Source : Team Orion