Differences

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--- tecnica:motori:keihin_vd_carburetor [2026/04/16 22:06] – [Starter System (Figure 4-16)] niccolo
+++ tecnica:motori:keihin_vd_carburetor [2026/04/16 22:54] (current) – [Fuel Supply System (Figure 4-15)] niccolo
@@ Line 70: / Line 70: @@
 ==== Fuel Supply System (Figure 4-15) ====
+Fuel from the fuel tank passes through the inlet vale into the float chamber. The fuel entering the chamber causes th float to rise until it shuts off the fuel valve, stopping flow at a level pre-determined by float level setting.
+The float chamber is vented to atmosphere through an air passage opening in the air cleaner mounting flange.
+{{.:keihin:fig-4-15.png?direct&400|Fuel Supply System}}
 ==== Starter System (Figure 4-16) ====
@@ Line 89: / Line 96: @@
 {{.:keihin:fig-4-17.png?direct&400|Idle and Slow Speed Circuit}}
+==== MidRange Slide Position and Fuel Discharge (Figure 4-18) ====
+As te throttle plate is opened, air flow increases through the carburetor and the pressure drop in the venturi near the needle jet increases.
+The low pressure in the venturi travels through the vacuum port in the vacuum piston to the chamber above the diaphragm. The chamber beneath the diaphragm is vented to atmospheric pressure by a passage from the chamber to the carburetor inlet. The higher pressure at the underside of the diaphragm overcomes spring pressure and moves the vacuum piston upward in proportion to the pessure difference between chambers.
+The tapered needle moves upward with the vacuum piston, opening the needle jet. The higher pressure in the float chamber forces fuel into the needle jet passage. Air at atmospheric pressure from the main air jet is forced through the main bleed tube opanings and mixes with the fuel. The fuel/air mixture is then delivered through the needle jet ino the air stream.
+==== High Speed Circuit Slide Position and Fuel Discharge (Figure 4-19) ====
+As the throtte plate is opened, the pressure difference betwneen the chambers above and below the diaphragm increases and the vacuum piston moves further upward.
+The venturi opening increases and the needle is lifted further out of the the needle jet. The quantity of fuel and the volume of air are simultaneously increased and metered to the proportions of engine demand by the variable venturi and needle lift. With the vacuum piston fully upward, the venturi opening is fully enlarged and the needle jet opening exposure to the air stream is at its maximum, Air and fuel supplies are now available in quantities sufficient to meet all engine demands.
+==== Accelerator Pump System (Figure 4-19) ====
 ===== The pilot screw =====