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techtalk:ref:carb07 [2019/10/14 23:03]
techtalk:ref:carb07 [2019/10/15 00:24]
hippysmack [Adjustable Main Jet (L76-87)]
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 |{{:​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))| |{{:​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))|
-===== EZ-Just ​Thumbscrew Mods =====+===== Idle Mixture ​Thumbscrew Mods =====
 Several mods to the thumbscrew have been done to make counting turns while turning the screw easier. \\ Several mods to the thumbscrew have been done to make counting turns while turning the screw easier. \\
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 {{:​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|}} \\ {{:​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|}} \\
-====== Adjustable Main Jet (L76-87) ====== 
-There is an adjustable main jet available from J&P Cycles or others. \\ 
-These work great and you don't have to fool around jet guessing whether you have the right size main jet or not. \\ 
-They are simple to adjust. Just wind it up to about 65 MPH and run it in until it misses and back it out about a full turn. ((oldnavy of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=877868&​page=2)) \\  
-This kit can be purchased online. It comes with an installation guide and index pointer. \\ 
-The tool marks inside of the float bowl (as installed) for drilling the proper sized hole to thread in the adjustable main jet.\\ 
-The kit can be purchased online. \\ 
-PDF instructions - [[http://​www.vtwinmfg.com/​instructions/​35/​35-0369.pdf]] \\ 
-{{:​techtalk:​ref:​carb:​keihin_butterfly_adjustable_main_jet_35-0369.jpg?​direct&​300|}} \\ 
-This replaces the main jet (has to be removed). \\ 
-The float bowl has to be removed to install the adjustable main jet. \\ 
-A guide tool is included with the kit to install the new jet to properly index the carburetor float bowl. \\ 
-A index pointer is installed in the guide, bowl reinstalled and the pointer is pushed down from inside the venture to dimple the bowl. \\ 
-The bowl is once again removed and a 1/​16"​-1/​8"​ pilot hole is drilled followed by a 15/64" bit. \\ 
-After checking for burrs, removing the index tool and guide and cleaning up, the adjustable jet is installed in the float bowl. \\ 
-(partially unscrew the small '​T'​ handle so that the needle in the adjustable jet is not exposed to accidental damage) \\ 
-Remove the nut from the adjustable jet, insert the jet through the 15/64" hole drilled earlier. \\ 
-Then re-tighten the bowl and gently screw in the '​T'​ handle to the needle seat and then back it out 4 turns. \\ 
-Finer tuning can be achieved by reading the spark plugs and small adjustments to the “T” handle. \\ 
-This adjustable jet eliminates the chore of carrying and continually changing different main jets with every change in exhaust system or air cleaner. \\ 
-The hole in the bowl for the '​T'​ handle jet has to be indexed correctly in order for this to work. \\ 
-The adjustable main jet is designed to operate in conjunction with a 1.80 main jet included with the kit. \\ 
-Make sure you record or remember the number of turns off the seat and back off the '​T'​ handle before removing the float bowl later. \\ 
-This will help prevent needle / jet interference when the float bowl is reinstalled. \\ 
-For initial adjustment (standard pipes and A/C) it's recommended that the adjustment needle be backed out four (4) turns from the seat. 
-The adjustable jet set screw is turned in, towards the float bowl to lean the fuel/air mixture and out from the float bowl to richen the mixture. \\ 
-Check plugs frequently after jet adjustment, exhaust or A/C to avoid too lean or too rich conditions. \\ 
-====== Andrews High Flow Accelerator Pump (Keihin butterfly) ====== 
-79-up 34mm Keihin carbs will not fill there accelerator pumps as quickly as the 76-78 38mm ones. ((Joe Minton Article "​Tuning HD's Keihin Carburetors"​)) \\ 
-The earlier pump would refill in about 1/2 second. The later one takes three seconds. \\ 
-The earlier pump will allow you to get by the choke and will help you catch the engine if you let the clutch out too fast at a red light. \\ 
-The main difference is the pump housing. The early accel pump passages had both an inlet and an outlet hole for gas routing. \\ 
-The Andrews pump is reportedly the same as Harley part (27364-76) for the early 38mm Keihins. \\ 
-Actually, if you can find a 38mm pump and drill the hole in your carb body, you'll have the old style accel pump. \\ 
-On 1980-1988 Keihin carbs, the stock accelerator pump is restricted by eliminating the check valves in the pump. A high flow accelerator pump puts them back. ((IronMick of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=93242)) \\ 
-The result is increased fuel flow through the pump and greatly improved low end and mid range throttle response. \\ 
-The Keihin butterfly carb already has an accelerator pump, so the Andrews high-flow pump body just replaces the stock one on the bottom of the float bowl. ((83XLX of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=2064358)) \\ 
-There is one on the [[https://​vtwin.parts/​index.php?​_route_=supplier/​v-twin/​sportster-1952-up/​fuel-air-system/​carburetor/​rebuild-kits/​harley-davidson-indian-motorcycle-keihin-carburetor-accelerator-pump-kit-35-9050&​limit=50|V-twin website]] called the Flowmaster accelerator pump. \\ 
-It has a V-twin part number of 35-9050, Manufacturer Keihin, Part Number: 269050. \\ 
-//​Flowmaster carb accelerator pump kit improves throttle response on Keihin carburetor models with a greater volume of fuel from the pump circuit//. \\ 
-Makes since as Andrews used to make the Flowmaster carb. \\ 
-The pump is listed as out of stock and has been since at least of march 2018 yet the listing is still up. \\ 
-In fact and according to the V-twin website, it's been discontinued and no replacement is listed. \\ 
-Installation instructions from Andrews is [[http://​www.andrewsproducts.com/​files/​assets/​carbpump1.pdf|here]]. \\ 
-Features: ((http://​www.johnnysreplacementparts.com/​product/​andrews-high-flow-accelerator-pump-kit-269050/​)) \\ 
-  * Improves throttle response 
-  * Larger fuel volume/​discharge 
-  * Fits 79-89 H-D using Keihin carburetor (except Flowmaster and CV carbs) 
-  * Easy to install 
-  * Fits 79-89 H-D with Keihin carb 
-  * Dimensions: 5"​x3"​x1";​ 0.3 pounds 
-A high flow accelerator pump is also a great all around upgrade for these carbs. ((oldnavy of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=877868&​page=2)) \\ 
-{{:​techtalk:​ref:​carb:​andrews_accel_pump_1_by_paraord.jpg?​direct&​300|}} ((photo by paraord of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​p=3908971)) {{:​techtalk:​ref:​carb:​andrews_accel_pump_2_by_paraord.jpg?​direct&​300|}} ((photo by paraord of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​p=3908971)) \\ 
-**How the High Flow Accelerator Pump should be installed**:​ ((Andrews Products, Inc. INSTALLATION INSTRUCTIONS 
-High Flow Accelerator Pump for Stock Keihin Carburetors For Stock Keihin Carbs from 1980-1988)) \\ 
-  - Remove float bowl from carburetor. There are four screws holding it in place. \\ It is not necessary to remove the entire carburetor from the engine to install your new high flow accelerator pump. 
-  - Clean any fuel residue from the bowl assembly and remove the stock accelerator pump housing. \\ It is held in place with three screws but one of them already has been removed with the bowl.  
-  - Position the bowl upside down for drilling a single hole through the bottom. 
-  - Any drill of approximately 1/16 diameter will be quite satisfactory. \\ The exact location for this hole is already marked with a dimple on the bottom of the float bowl casting as shown in photo below. \\ {{:​techtalk:​ref:​carb:​keihin_butterfly_carb5.2_by_brendan_-_annotated.jpg?​direct&​300|}} ((photo by brendan of the XLFORUM, annotated by Hippysmack http://​xlforum.net/​forums/​showthread.php?​p=5759323&​highlight=keihin+butterfly#​post5759323)) 
-  - Feed the drill through until it breaks out into the float chamber. \\ Don’t worry if the hole breaks into either a cross drilled passage or through the actual bottom of the bowl. \\ The location is not critical as long as fuel can feed through into the accelerator pump. 
-  - Thoroughly clean any drill chips from the bowl. There is a small bypass hole in the bottom of the bowl which does not have to be plugged. \\ Several earlier magazine articles have recommended plugging this hole but there will be no measurable benefit from doing so. 
-  - Install the new accelerator pump housing onto the bowl with the two shortest screws of the original three. \\ Make sure that the two small O-ring seals are installed; \\ One into a recess in the pump housing. \\ The second into a recess into the bottom of the bowl casting. 
-  - If the accelerator pump jet needs to aimed differently,​ now is the time to do this. \\ With a small adjustable wrench, carefully reposition the pump jet by gently turning it in the bowl casting (it’s a press fit). 
-  - Reinstall the bowl and pump assembly back onto the carburetor body to complete the job. \\ The extra fuel from the larger capacity pump should result in smoother, quicker throttle response especially off idle or at low RPM. 
-**Alternative using CV accelerator pump**: \\ 
-It looks like Keihin made all these covers so any of the basic raw castings can have additional operations incorporated to be used in any of their many configurations. ((chevelle of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=2009248)) \\  
-The stock pump cover for non CV Harley carbs (2-2) uses the same passage for supply and pump shot. \\ 
-The high flow cover uses separate passages for supply and pump shot (4-2). \\ 
-It also contains a loose check ball in the passage. \\ 
-The stock cover is not easily owner modified to incorporate separate passages and check ball (2-2). \\ 
-The Keihin CV pump cover (4-1) (left in center photo) is a high flow cover just as the Andrews. \\ 
-The only difference is the (4-1) cover has an extra counter-bore compared with stock non CV. \\ 
-The CV cover is made with packing bore in cover. \\ 
-The non CV is made with packing bore in bowl body. \\ 
-It seems the CV (4-1) cover can be made to work in a non CV if (2) square packing are used, one in cover and one in carb body. \\ 
-Note: All orifices in covers are the same. \\ 
-{{:​techtalk:​ref:​carb:​acel_pumps_1_by_chevelle.jpg?​direct&​300|}} ((photo by chevelle of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=2009248)) {{:​techtalk:​ref:​carb:​acel_pumps_2_by_chevelle.jpg?​direct&​300|}} ((photo by chevelle of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=2009248)) {{:​techtalk:​ref:​carb:​acel_pumps_3_by_chevelle.jpg?​direct&​300|}} ((photo by chevelle of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=2009248)) \\