Hey guys, my question is at the bottom, but could you read thru my deductive reasoning on how all this works. Let me know if I'm not understanding properly.
From the airbox, on the very rim of each of the carb air intakes are two holes that lead up to the slider chamber. As air rushes past the rim of the carb these holes are pressurized by the ram air which in turn pressurize the underside of the slider diaphragm which in turn raises the sliders. The more throttle you give, the faster the ram air is and the higher the sliders will raise which in turn open the carb throat further and slide the needle further open.
The air trapped on the top side of the slider diaphragm is evacuated by a few holes located near the center of the slider itself. These holes are small roughly 0.5mm. Since one end is at the venturi of the carb this means a vacuum is provided going to the other end up in the top side of the slider diaphragm helping to promote the evacuation. The slider is normally closed via a spring on the top side of the diaphram with enough tension to prevent opening while the motor is at idle, in other words the ram air plus the vacuum effect is not enough to move the slider upwards against the spring. Obviously engineers have determined the size of the ram air holes, the evacuation holes and the spring tension to all work in harmony with desired slider opening positions relative to throttle/engine rpm.
My 2009 GS500F has vacuum valves at the top of each slider chamber (top side of diaphram). These valves are normally closed. When the valves are activated they open a 4mm port directly to the outside air (actually there is a 8" tube with a sponge filter at the end). I don't know if all 2009's have this or was this originally a California emissions thing?!?
I want to know what the function of those valves are for. Is it some weird emmission thing, I don't think so because I can't see how gases can work their way up into that chamber and there is no residue. My current theory is that the evacuation of air can now exit via this 4mm hole instead of the 0.5mm holes in the slider. Maybe this would provide a faster throttle response. There is an electrical switch/solenoid (the air solenoid) that opens a vacuum line leading to both of these valves. I want to know what triggers that solenoid to open the vacuum lines effectively activating those slider chamber valves?
I'm wondering if the switch is activated based on motor temperature, or simply just that the bike is running, or more complex based on rpm or speed, or other?!?
This thread may be relevant to your interests: http://gstwins.com/gsboard/index.php?topic=72140.0