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techtalk:ref:carb07 [2019/08/11 00:15]
hippysmack [Part Considerations]
techtalk:ref:carb07 [2019/10/15 03:24] (current)
hippysmack [Velocity Stack]
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 ====== REF: Carburetor, Intake Manifold & Exhaust ====== ====== REF: Carburetor, Intake Manifold & Exhaust ======
-====== ​CV Carb Upgrades ====== +====== ​Keihin ​Carb Upgrades ​- Butterfly and CV Types ====== 
-====== Replacing the Plastic Fuel Inlet Fitting ====== +\\ 
-The factory fuel elbow found on CV carburetors has been prone to cracking and leaking. \\+ 
 +====== Extended Idle Speed Screw ====== 
 +Below is a CVP stainless steel idle speed screw for Harley CV and Keihin butterfly style carburetors. \\ 
 +With the extended thumbscrew, idle speed can be adjusted by hand. \\ 
 +It's also slotted for a large tipped screwdriver if longer reach is still needed. \\ It also includes a stainless steel spring. \\ 
 +For use on all Harley CV40 and Keihin butterfly style carbs 1981-2006. ((https://​cv-performance.com/​harley-idle-speed-screw)) \\ 
 + 
 +|Long idle speed screw on a Keihin CV. ((photo by Hippysmack))| 
 +|{{:​techtalk:​ref:​carb:​cv_carb_with_extended_idle_speed_screw_by_hippysmack.jpg?​direct&​300|}}| 
 + 
 +====== Aftermarket Idle Mixture Screws and Mods ====== 
 +\\ 
 +===== EZ-Just Mixture Screws ===== 
 +The EZ-Just mixture screw (for L76-87 or 88-06 models) ((https://​cv-performance.com/​ez-just-mixture-screw-81-87-harley-keihin)) ) can be purchased with an extended screw head for hand tuning. \\ You can buy packing from CVP also in case yours has been damaged or is not functioning properly. \\ But, check your local regulations before changing this out to an aftermarket part. \\ You can also find, buy or barter for used parts. \\ ("​Please note: it is a violation of federal law to tamper with or disable any emission or noise control device. That is your PSA for the day"). ((XLForum member - chrishajer)) \\ 
 + 
 +If you still have the factory plug over the mixture screw, you'll need to drill it out to access the screw. \\ 
 +To keep from drilling too far into the plug, you can use some electrical tape around the drill bit to mark the depth to drill. \\ 
 +Then pry the plug out using a pick or you could twist a small sheet metal screw into the hole to pull the plug out. \\ 
 +With the plug removed clean the area around the mixture screw so no metal fragments remain. \\ 
 +{{techtalk:​evo:​carb:​cv40-imscap-drillbit.jpg?​300|}} ((photo by cantolina of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=14949)) Circled area is where you drill out the plug. {{:​techtalk:​ref:​carb:​cv_carb_bottom_by_cantolina.jpg?​direct&​300|}} ((photo by cantolina of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=14949)) 
 + 
 +The EZ-Just mixture screw must be threaded in completely (lightly seated) prior to backing out and making final adjustments. \\ 
 +Typically between 10-12 full rotations of the screw to seat. \\ 
 +If you can see more than 1-2 threads after seating the screw, the screw is not screwed in completely. \\ 
 +This could result in the screw falling out during operation. \\ 
 +If you have trouble fully threading the EZ-Just, this indicates the inside threads of the carburetor need cleaning or have a damaged thread inside. \\ 
 +Working the screw in/out with light machine oil (3-In-1 or other) will often help work past any carbon build up inside the carburetor threads. \\ 
 + 
 +The packing for the EZ-Just is the same as OEM: \\ 
 +screw, spring, washer, O-ring. \\ 
 +{{:​techtalk:​ref:​carb:​ez_just_idle_mixture_screw_1_by_hippysmack.jpg?​direct&​300|}} ((photo by Hippysmack)) \\ 
 + 
 +===== 88-06 ===== 
 +This screw is billed as "​Easily tune and adjust your idle mixture without burning your hands or fumbling with a screwdriver."​ ((https://​cv-performance.com/​ez-just-mixture-screw)) \\ 
 +This is not entirely true as you have to get your hand between the exhaust and air cleaner. \\ 
 + 
 +Tuning and installation tips here at [[https://​cv-performance.com/​harley_mixture_screw_tuning/​|CV Performance.com]]. \\ 
 +The carburetor will need to be removed from the manifold so refer to your factory shop manual for this procedure.  
 +With the carburetor removed, place upside down on a sturdy work surface. \\ 
 +The float bowl doesn'​t need to be removed unless you have to issues removing the factory packing and/or need to blow out the passageway. \\ 
 +If you take off the bowl, be sure to check the float setting before reinstalling the bowl. \\ 
 + 
 +|  EZ-Just Screw in it's '​lightly seated'​ position. ((photo by Matt Black of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=2068828&​page=6)) ​ || 
 +|{{:​techtalk:​ref:​carb:​ez_screw_lightly_seated_1_by_matt_black.jpg?​direct&​300|}}|{{:​techtalk:​ref:​carb:​ez_screw_lightly_seated_2_by_matt_black.jpg?​direct&​300|}}| 
 + 
 +|Comparison to OEM. ((photo by Hippysmack))| ​ As installed on bottom of carb. ((photos by Hippysmack)) ​ || 
 +|{{:​techtalk:​ref:​carb:​ez-just_88-06_a-f_mixture_screw_1_by_hippysmack.jpg?​direct&​300|}} ((photo byHippysmack))| {{:​techtalk:​ref:​carb:​ez-just_88-06_a-f_mixture_screw_2_by_hippysmack.jpg?​direct&​300|}} ((photo byHippysmack))|{{:​techtalk:​ref:​carb:​ez-just_88-06_a-f_mixture_screw_3_by_hippysmack.jpg?​direct&​300|}} ((photo byHippysmack))| 
 + 
 +===== Idle Mixture Thumbscrew Mods ===== 
 +Several mods to the thumbscrew have been done to make counting turns while turning the screw easier. \\ 
 + 
 +|The aftermarket thumb screw head doesn'​t a slot for a screwdriver (which also serves as a visual for position). \\ A small hole drilled off center will give a visual position of the screw for adjustment later. ((photos by sifty of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=1592463&​page=48))||  
 +|{{:​techtalk:​evo:​carb:​idle_mixture_screw_3_by_sifty.jpg?​direct&​300|}}|{{:​techtalk:​evo:​carb:​idle_mixture_screw_4_by_sifty.jpg?​direct&​300|}}| 
 + 
 +This replacement needle makes it so much easier to adjust the idle mixture. ((Folkie of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=183642)) \\ 
 +However, it is easier to count the turns by hand with this mod. \\ 
 +A spigot was added to the face of the knob. \\ 
 +The needle was screwed in all the way to gentle seat. \\ 
 +Then the side nearest the air cleaner (right of bike) was marked to index when to stop turning to the right. \\ 
 +The needle was then removed, drilled and tapped (10 BA) for the spigot. \\ 
 +You can also drill hole through the knob from side to side and Superglue a screw in it. ((Hot Rod Sporty of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=183642)) \\ 
 + 
 +The EZ-Just makes it easy to adjust the idle mixture by hand without a screwdriver. \\ 
 +But, if you've gone 3 to 3-1/2 turns out, then change to the next biggest slow jet. ((Folkie of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=183642)) \\ 
 + 
 + 
 +|  Spigot installed to count the turns. ((photo by Folkie of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=183642)) ​ | 
 +|{{:​techtalk:​evo:​carb:​idle_mixture_screw_mod_by_folkie.jpg?​direct&​300|}}| 
 + 
 +===== Modding a Factory Mixture Screw ===== 
 + 
 +This was done to extend the factory idle mixture screw. \\ 
 +A piece of 3/16" brass tubing and a knurled nut from the hardware store. \\ 
 + 
 +|  Factory idle mixture screw extended. ((photos by tchuck of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=183642)) ​ || 
 +|{{:​techtalk:​evo:​carb:​idle_mixture_screw_mod_2_by_tchuck.jpg?​direct&​300|}}|{{:​techtalk:​evo:​carb:​idle_mixture_screw_mod_3_by_tchuck.jpg?​direct&​300|}}| 
 + 
 +\\ 
 + 
 +===== Modding a Factory Idle Speed Screw ===== 
 +You can stick a dime in the adjuster screw slot and braze it to the screw to make future adjustments by hand. \\ 
 +{{:​techtalk:​ref:​carb:​keihin_carb_1_by_ddddylan_-_annotated.jpg?​direct&​300|}} ((photo by DDDDylan of the XLFORUM, annotated by Hippysmack)) 
 +====== Velocity Stack ====== 
 + 
 +A velocity stack has been used (between the air cleaner and carb) to reduce turbulence while increasing velocity for optimal fuel mixture. ((https://​cv-performance.com/​v-ductor)) \\ 
 +It's doesn'​t block or reduce air flow and is suppose to greatly improve mileage by encouraging a more complete burn of the air/fuel mixture. \\ 
 +"​Bolt-on performance that installs in minutes"​ although no performance enhancements have been found while using them. \\ 
 +Aluminum type velocity stacks like the "​V-Ductor"​ from CV Performance have been used and tested to find no HP gains from them. 
 +Some may still cite 'peace of mind' and there is no downside to using it other than the price. 
 +It requires a total of 2 gaskets (included) to install. ((photos by Hippysmack)) \\ 
 + 
 +This is a "​V-Ductor"​ from CV Performance. ((https://​cv-performance.com/​v-ductor-installation)) \\ 
 +|{{:​techtalk:​ref:​carb:​velocity_stack_1_by_hippysmack.jpg?​direct&​300|}}|{{:​techtalk:​ref:​carb:​velocity_stack_2_by_hippysmack.jpg?​direct&​300|}}| 
 + 
 +  * Remove the air cleaner backing plate. 
 +  * Place a gasket onto the backing plate, then the V-Ductor and another gasket (2 supplied in the kit). 
 +  * The smaller end of the cone faces into the carb. 
 +  * Install the new assembly onto the carb and torque to factory specs. 
 +  * backing plate with as normal against the V-Ductor. Installation of your air box will vary depending upon the  
 + 
 +|{{:​techtalk:​ref:​carb:​velocity_stack_3_by_hippysmack.jpg?​direct&​300|}}|{{:​techtalk:​ref:​carb:​velocity_stack_4_by_hippysmack.jpg?​direct&​300|}}|{{:​techtalk:​ref:​carb:​velocity_stack_5_by_hippysmack.jpg?​direct&​300|}}| 
 + 
 + 
 + 
 +====== Replacing the Plastic Fuel Inlet Fitting with a Brass 90 Degree ​Fitting ====== 
 +The factory fuel elbow found on Keihin ​carburetors has been prone to cracking and leaking. \\
 Also the manner in which the plastic elbow is formed onto a brass insert restricts flow. \\ Also the manner in which the plastic elbow is formed onto a brass insert restricts flow. \\
 It's made of a combination of molded plastic on the outside with a brass nipple installed on the inside of the carb. \\ It's made of a combination of molded plastic on the outside with a brass nipple installed on the inside of the carb. \\
 The plastic attached to the brass nipple can crack or break off when removing the original crimp clamp or if over tightened. \\ The plastic attached to the brass nipple can crack or break off when removing the original crimp clamp or if over tightened. \\
 Stress can also break it while removing / installing the carb if the attached hose gets caught on something and pulled. \\ Stress can also break it while removing / installing the carb if the attached hose gets caught on something and pulled. \\
-Replacing the factory elbow with a brass one will increase gas flow (especially with a vacuum-less petcock). \\ +Replacing the factory elbow with a brass one can increase gas flow (especially with a vacuum-less petcock). \\ 
-|  Factory plastic fuel inlet elbow. ((photo by Hippysmack)) ​ |+|  Factory plastic fuel inlet elbow on Keihin CV. ((photo by Hippysmack)) ​ |
 |{{:​techtalk:​ref:​carb:​cv_fuel_inlet_elbow_mod_7_by_hippysmack.jpg?​direct&​300|}}| |{{:​techtalk:​ref:​carb:​cv_fuel_inlet_elbow_mod_7_by_hippysmack.jpg?​direct&​300|}}|
 +
 +|  Keihin butterfly (non CV). Here is on way to do it. Break the plastic off and run a hose on the factory brass nipple. ((photos by Hopper of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=209347&​highlight=float+level&​page=21)) ​ |||
 +|{{:​techtalk:​ref:​carb:​keihin_butterfly_carb_23_by_hopper.jpg?​direct&​300|}}|{{:​techtalk:​ref:​carb:​keihin_butterfly_carb_24_by_hopper.jpg?​direct&​300|}}|{{:​techtalk:​ref:​carb:​keihin_butterfly_carb_25_by_hopper.jpg?​direct&​300|}}|
 +
 +Replacing the the hipple with a brass elbow is detailed below. \\
 ===== Tools ===== ===== Tools =====
  
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 You need an elbow designed for this application for best results. \\ You need an elbow designed for this application for best results. \\
-The MoCo may still sell both an OEM and brass inlet that can be pressed in (arbor press or large vise). \\ +The MoCo may still sell both an OEM and brass inlet (27371-76a) ​that can be pressed in (arbor press or large vise). \\ 
-Some catalogs carry an OEM replacement inlet but it has the same plastic elbow (not recommended). \\+You can search the brass elbow part number online. ​Some catalogs carry an OEM replacement inlet but it has the same plastic elbow (not recommended). \\
 While others sell a brass inlet made from a 2-piece design (also not recommended). \\ While others sell a brass inlet made from a 2-piece design (also not recommended). \\
 CV Performance sells a solid elbow and a hose clamp as a kit. \\ CV Performance sells a solid elbow and a hose clamp as a kit. \\
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 ===== The Process ===== ===== The Process =====
 +The carb below is a Keihin CV from a 98 S model but the process for replacing the elbow is the same for all Keihin carbs. \\
 It's a fairly simple job to replace the fuel inlet. \\ It's a fairly simple job to replace the fuel inlet. \\
 Instructions are also here at the CVP website: [[https://​cv-performance.com/​harley-fuel-elbow-replacement]] Instructions are also here at the CVP website: [[https://​cv-performance.com/​harley-fuel-elbow-replacement]]
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 **Assemble the puller**: \\ **Assemble the puller**: \\
 +I pre-made puller was bought for the pics below. \\
 +But you can also use a 1/​4'​x20 threaded rod about a foot long screwed into the fitting. \\
 +Then slip a thin piece of pipe nipple over the rod with a washer and nut onto the end of the rod. ((tgrover of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=501871)) \\
 +
 Place the spacer (or deep socket) over the brass nipple. \\ Place the spacer (or deep socket) over the brass nipple. \\
 Thread the nut onto the bolt up to the screw head then add the washer. \\ Thread the nut onto the bolt up to the screw head then add the washer. \\
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 Once the piece begins to move it will pull out like butter. ((photos by Hippysmack)) \\ Once the piece begins to move it will pull out like butter. ((photos by Hippysmack)) \\
 Once the nipple is out, you may have to '​pop'​ the spacer of as it may wedge against the carb. \\ Once the nipple is out, you may have to '​pop'​ the spacer of as it may wedge against the carb. \\
 +
 +A socket may be used as a spacer with the appropriate length bolt. \\
 +{{:​techtalk:​ref:​carb:​socket_as_spacer_for_removing_cv_carb_inlet_by_matt_black.jpg?​direct&​300|}} ((photo by Matt Black of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​p=5685578&​highlight=fuel+inlet+elbow#​post5685578)) \\
  
 {{:​techtalk:​ref:​carb:​cv_fuel_inlet_elbow_mod_17_by_hippysmack.jpg?​direct&​300|}} {{:​techtalk:​ref:​carb:​cv_fuel_inlet_elbow_mod_18_by_hippysmack.jpg?​direct&​300|}} {{:​techtalk:​ref:​carb:​cv_fuel_inlet_elbow_mod_19_by_hippysmack.jpg?​direct&​300|}} ​ {{:​techtalk:​ref:​carb:​cv_fuel_inlet_elbow_mod_17_by_hippysmack.jpg?​direct&​300|}} {{:​techtalk:​ref:​carb:​cv_fuel_inlet_elbow_mod_18_by_hippysmack.jpg?​direct&​300|}} {{:​techtalk:​ref:​carb:​cv_fuel_inlet_elbow_mod_19_by_hippysmack.jpg?​direct&​300|}} ​
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 This will take the blow off the carb body and internals. \\ This will take the blow off the carb body and internals. \\
 |Double check alignment before installing. ((photo by Hippysmack))|Tap the elbow in with a hammer. ((photo by Hippysmack))|Or pull it in with a vise with soft jaws. ((photo by Hippysmack))| |Double check alignment before installing. ((photo by Hippysmack))|Tap the elbow in with a hammer. ((photo by Hippysmack))|Or pull it in with a vise with soft jaws. ((photo by Hippysmack))|
-|{{:​techtalk:​ref:​carb:​cv_fuel_inlet_elbow_mod_29_by_hippysmack.jpg?​direct&​300|}}|{{:​techtalk:​ref:​carb:​cv_fuel_inlet_elbow_mod_35_by_hippysmack.jpg?​direct&​300|}}|{{:​techtalk:​ref:​carb:cv_fuel_inlet_elbow_mod_36_by_hippysmack.jpg?​direct&​300|}}|+|{{:​techtalk:​ref:​carb:​cv_fuel_inlet_elbow_mod_29_by_hippysmack.jpg?​direct&​300|}}|{{:​techtalk:​ref:​carb:​cv_fuel_inlet_elbow_mod_35_by_hippysmack.jpg?​direct&​300|}}|{{:​techtalk:​ref:​tools:soft_jaw_vise_for_holding_carb_2_by_hippysmack.jpg?​direct&​300|}}|
  
 The brass inlet will self-seal when pressed in as long as the carb inlet passage hole is free of debris and not damaged, stretched, or cracked. \\ The brass inlet will self-seal when pressed in as long as the carb inlet passage hole is free of debris and not damaged, stretched, or cracked. \\
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 Blow the passage out again to ensure of no debris before installing the bowl. ((photos by Hippysmack)) \\ Blow the passage out again to ensure of no debris before installing the bowl. ((photos by Hippysmack)) \\
-{{:​techtalk:​ref:​carb:​cv_fuel_inlet_elbow_mod_40_by_hippysmack.jpg?​direct&​300|}} {{:​techtalk:​ref:​carb:​cv_fuel_inlet_elbow_mod_41_by_hippysmack.jpg?​direct&​300|}}+{{:​techtalk:​ref:​carb:​cv_fuel_inlet_elbow_mod_40_by_hippysmack.jpg?​direct&​300|}} {{:​techtalk:​ref:​carb:​cv_fuel_inlet_elbow_mod_41_by_hippysmack.jpg?​direct&​300|}} ​{{:​techtalk:​ref:​carb:​cv_fuel_inlet_elbow_mod_42_by_hippysmack.jpg?​direct&​300|}} \\ 
 + 
  
 \\ \\
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