Differences

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--- tecnica:motori:keihin_vd_carburetor [2026/04/17 15:50] – [Accelerator Pump System (Figure 4-19)] niccolo
+++ tecnica:motori:keihin_vd_carburetor [2026/04/17 18:22] (current) – [Nomenclature] niccolo
@@ Line 30: / Line 30: @@
 {{.:keihin:keihin-slide-diaphragm-needle_annotated.jpg?480|Slide, diaphragm and needle}}
-{{.:keihin:keihin-float-bowl.jpg?480|Float bowl}}
+{{.:keihin:keihin-float-bowl_annotated.jpg?480|Float bowl}}
+===== Carburetor Functioning =====
+Excerpts from the Service Manual of military motorcycle Harley Davidson MT-350.
-  * **Side view**
-    * Air intake from the airbox.
-    * Choke valve seat.
-    * Pilot screw seat.
-    * Duct for the high intake vacuum that acts on the //air cut-off valve// diaphragm.
-    * //Air cut-off valve//: air in (normally open).
-    * //Air cut-off valve//: air out.
-  * **Float chamber**
-    * Main jet
-    * Slow jet
-    * Starter jet (choke/enrichment jet)
-    * Float valve
-    * Breath hole
-  * **Vacuum chamber**
-    * Air intake from the airbox.
-    * Starter (choke enrichment) air supply passage.
-    * Air intake for the //air cut-off valve//: normally open. It closes on deceleration (high rpm + throttle closed).
-    * Air intake for the slow jet.
-    * Air intake for the choke.
-    * Small vent that connects the chambers above and below the diaphragm: it acts as a vacuum/pressure control and damping system.
-  * **Airbox view**
-    * Air intake for the pilot and the //air cut-off valve// circuits.
-  * **Engine view, bottom**
-    * Primary pilot outlet port. This is the main idle fuel outlet, controlled by slow jet and pilot screw.
-    * Pilot progression ports. They provide staged extra fuel during throttle opening.
-  * **Engine view, top**
-    * Starter (enricher) outlet port and vacuum pickup port that operates the //air cut-off valve//.
-  * **Slide, diaphragm, needle**
-    * Slide lift holes: vacuum bleed holes that control how quickly pressure changes reach the above diaphragm chamber.
-  * **Float bowl**
-    * Drain screw.
-    * Drain conduct.
-===== Functioning =====
 ==== Fuel Supply System (Figure 3-3) ====
@@ Line 113: / Line 82: @@
 {{.:keihin:figure_3-7.png?400|High Speed Circuit Slide Position and Fuel Discharge}}
+===== The air cut off valve =====
+{{.:keihin:air-cut-off-valve_transient-enrichment-system.png?480|}}
 ===== The pilot screw =====
@@ Line 131: / Line 102: @@
       * Easier starting.
       * Reduced decel popping.
-===== The air cut off valve =====
-{{.:keihin:air-cut-off-valve_transient-enrichment-system.jpg?400|}}
 ===== Web References =====
@@ Line 142: / Line 109: @@
   * **[[https://www.venturerider.org/forum/forums/topic/65604-what-is-the-name-and-purpose-of-this-carburetor-part/|"Coasting enrichment valve" or "air cut-off valve" or "transient enrichment valve"]]**
   * **[[https://www.vessels-clan.com/jay/1200s/cv/|Keihin CV Carburetor Diagrams]]**
-  * **[[https://assets.publishing.service.gov.uk/media/5a81fe69ed915d74e623536d/2017-13198.pdf|Harley Davidson Manufacturer's Service Manual MT350 (84771039)]]**
+  * **[[https://assets.publishing.service.gov.uk/media/5a81fe69ed915d74e623536d/2017-13198.pdf|Harley Davidson Manufacturer's Service Manual MT350 (84771039)]]** - {{.:keihin:harley-davidson--mt350-service-manual-84771039.pdf|Local PDF copy}}