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techtalk:ih:carb01q [2019/10/17 02:02]
hippysmack [Choke Shaft]
techtalk:ih:carb01q [2023/12/29 19:33]
hippysmack
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 ====== Disassembly ====== ====== Disassembly ======
  
-  * Removing the carb from the bike should be straight forward. First thing when it is out is to check the pilot screw setting. ((IronMick of the XLFORUM ​http://​xlforum.net/​forums/showthread.php?t=185361)) \\ Turn it all the way in until gently seated counting the number of 1/4 turns; then write this number down; then reset it.+  * Removing the carb from the bike should be straight forward. First thing when it is out is to check the pilot screw setting. ((IronMick of the XLFORUM ​https://www.xlforum.net/​forum/sportster-motorcycle-forum/​sportster-motorcycle-era-specific-and-model-specific/​ironhead-sportster-motorcycle-talk-1957-1985/​47937-cleaning-a-carb?t=185361)) \\ Turn it all the way in until gently seated counting the number of 1/4 turns; then write this number down; then reset it.
 This rig works well to get the carb off to fit the heat block (if applicable) without having to take off the horn and ignition switch brackets. \\ This rig works well to get the carb off to fit the heat block (if applicable) without having to take off the horn and ignition switch brackets. \\
 1/2" deep socket, 3/8" drive, universal joint and 6" extension. \\ 1/2" deep socket, 3/8" drive, universal joint and 6" extension. \\
-{{:​techtalk:​ih:​carb:​keihin_butterfly_carb_7_by_hopper.jpg?​direct&​300|}} ((photo by Hopper of the XLFORUM ​http://​xlforum.net/​forums/showthread.php?​t=276157&​page=3))+{{:​techtalk:​ih:​carb:​keihin_butterfly_carb_7_by_hopper.jpg?​direct&​300|}} ((photo by Hopper of the XLFORUM ​https://www.xlforum.net/​forum/sportster-motorcycle-forum/​sportster-motorcycle-era-specific-and-model-specific/​ironhead-sportster-motorcycle-talk-1957-1985/​55576-how-to-tune-keihin-carbs-links/​page3?​t=276157&​page=3))
  
   * **Pilot screw**:   * **Pilot screw**:
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     * **Note**: Some carbs, notably 1966 to 1978 Sportster carbs, do not have the O-ring and washer in the pilot screw passage.     * **Note**: Some carbs, notably 1966 to 1978 Sportster carbs, do not have the O-ring and washer in the pilot screw passage.
   * **Float bowl**:   * **Float bowl**:
-    * Remove the three screws and washers holding the bowl on the carb body.+    * Remove the Four screws and washers holding the bowl on the carb body.
     * Removing the float bowl will also allow you to remove the accelerator pump rod and boot and access to the jets. \\ Be careful not to damage the accel pump nozzle and overflow pipe which are built into the bowl.     * Removing the float bowl will also allow you to remove the accelerator pump rod and boot and access to the jets. \\ Be careful not to damage the accel pump nozzle and overflow pipe which are built into the bowl.
     * Remove the screw that holds the float pin, pin and float.     * Remove the screw that holds the float pin, pin and float.
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 You can purchase individual parts or a rebuild kit. \\ You can purchase individual parts or a rebuild kit. \\
 The kits will not have needles, jets or the spring, washer & o-ring for the Idle Mixture Screw. \\ The kits will not have needles, jets or the spring, washer & o-ring for the Idle Mixture Screw. \\
-It's best to get the rebuild kit with Viton rubber. \\+It's best to get the rebuild kit with Viton rubber ​because it doesn'​t swell due to modern gas. \\
 The HD rebuild kit is part# 27006-92T. \\ The HD rebuild kit is part# 27006-92T. \\
 [[https://​www.amazon.com/​exec/​obidos/​ASIN/​B009CA2SEU/​cookinexperi-20|V-Twin Viton Rebuild Kit]]: #35-9176. \\ [[https://​www.amazon.com/​exec/​obidos/​ASIN/​B009CA2SEU/​cookinexperi-20|V-Twin Viton Rebuild Kit]]: #35-9176. \\
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 Float Valve: \\ Float Valve: \\
 The 3-sided valve (left below) '​may'​ sit cock-eyed in the seat sometimes and cause a leak. ((IronMick of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=1760294&​page=2)) The four sided (right below) valve is '​supposed'​ to be an improved design. \\ The 3-sided valve (left below) '​may'​ sit cock-eyed in the seat sometimes and cause a leak. ((IronMick of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=1760294&​page=2)) The four sided (right below) valve is '​supposed'​ to be an improved design. \\
-{{:​techtalk:​ih:​carb:​float_needles_by_county_fair_-_cropped.jpg?​direct&​300|}} ((photo by County Fair of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=1760294&​page=2)) \\+Also check new float valves for manufacturing errors. The glue holding the rubber on has been known to have spilled onto the rubber causing a bad seat. \\ 
 +{{:​techtalk:​ih:​carb:​float_needles_by_county_fair_-_cropped.jpg?​direct&​300|}} ((photo by County Fair of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=1760294&​page=2)) {{:​techtalk:​ih:​carb:​glue_on_inlet_needle_by_flthd31.jpeg?​direct&​300|}} ((photo by flthd31 of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​p=5846205#​post5846205)) \\
  
 The float needle should just kiss the seat with no extra pressure. Aftermarket float valves have a spring loaded pin under the float tab. So when the valve tip closes onto the seat, you can still push the valve down further. The valve should '​just'​ close when measuring the float level. Pushing further in from there will not close the valve any further. But it will cause you to set the float level wrong. The valve should be a light seat when measuring. Some aftermarket float needles with the spring loaded pin also have a defective neoprene tip on the other end (which does not seal even when set right). ((Hopper of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=1526333&​highlight=float+level&​page=4)) Since the tip on the needle on aftermarket ones don't work well, some would use the old original one (solid pin) to get a better measurement. ((Smerch of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=1526333&​highlight=float+level&​page=4)) Beats assembling the carb only to have it sit there and flood with gas. Also make sure you have the float valve for the correct type of Keihin carb. The aftermarket valves are a little taller. \\ The float needle should just kiss the seat with no extra pressure. Aftermarket float valves have a spring loaded pin under the float tab. So when the valve tip closes onto the seat, you can still push the valve down further. The valve should '​just'​ close when measuring the float level. Pushing further in from there will not close the valve any further. But it will cause you to set the float level wrong. The valve should be a light seat when measuring. Some aftermarket float needles with the spring loaded pin also have a defective neoprene tip on the other end (which does not seal even when set right). ((Hopper of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=1526333&​highlight=float+level&​page=4)) Since the tip on the needle on aftermarket ones don't work well, some would use the old original one (solid pin) to get a better measurement. ((Smerch of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=1526333&​highlight=float+level&​page=4)) Beats assembling the carb only to have it sit there and flood with gas. Also make sure you have the float valve for the correct type of Keihin carb. The aftermarket valves are a little taller. \\
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 ==== Choke Shaft ==== ==== Choke Shaft ====
-  * On 76-78 carbs, check where the choke detent plate attaches to the shaft can get loose and sloppy. \\ This joint can be brazed to tighten it back up and get better choke action. +  * On 76-78 carbs, check where the choke detent plate attaches to the shaft can get loose and sloppy. ​((sportsterpaul'​s Keihin Rebuild Video https://​www.youtube.com/​watch?​v=f_Ek37GEEN4&​feature=youtu.be)) ​\\ This joint can be brazed to tighten it back up and get better choke action. 
-  * During a backfire, the choke can slap all the way shut. \\ Then you kick it 5,000 times wondering what's wrong, you've flooded it, the plug's get wet and you're pushing it. \\ You can put a 0-80 screw into the lower hole in the detent plate to keep the choke plate from slamming shut and causing problems starting. \\ These holes are for a ball detent on the back side of the detent plate. \\ By installing a little 0-80 screw right there, when the bike backfires and they always do, the choke doesn'​t fully close and will save you a lot of grief. +  * During a backfire, the choke can slap all the way shut. ((sportsterpaul'​s Keihin Rebuild Video https://​www.youtube.com/​watch?​v=f_Ek37GEEN4&​feature=youtu.be)) ​\\ Then you kick it 5,000 times wondering what's wrong, you've flooded it, the plug's get wet and you're pushing it. \\ You can put a 0-80 screw into the lower hole in the detent plate to keep the choke plate from slamming shut and causing problems starting. \\ These holes are for a ball detent on the back side of the detent plate. \\ By installing a little 0-80 screw right there, when the bike backfires and they always do, the choke doesn'​t fully close and will save you a lot of grief. 
-  * When hooking up the choke cable, if you put the mounting screw down, you can't get the air filter on. \\ You need to tighten it with the screw pointing up, at least the after-market air filters. \\ That chrome back plate, when it slips on, there'​s not enough clearance down there if the screw points down. +  * When hooking up the choke cable, if you put the mounting screw down, you can't get the air filter on. ((sportsterpaul'​s Keihin Rebuild Video https://​www.youtube.com/​watch?​v=f_Ek37GEEN4&​feature=youtu.be)) ​\\ You need to tighten it with the screw pointing up, at least the after-market air filters. \\ That chrome back plate, when it slips on, there'​s not enough clearance down there if the screw points down. 
  
 {{:​techtalk:​ih:​carb:​keihin_butterfly_choke_shaft_maintenance_by_hopper_-_annotated_by_hippysmack.jpg?​direct&​300|}} ((photo by Hopper of the XLFORUM, annotated by Hippysmack)) \\ {{:​techtalk:​ih:​carb:​keihin_butterfly_choke_shaft_maintenance_by_hopper_-_annotated_by_hippysmack.jpg?​direct&​300|}} ((photo by Hopper of the XLFORUM, annotated by Hippysmack)) \\
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 The change was made after the Sportster began using the Keihin carburetor so this would'​ve affected the L76 and E77 carbs. \\ The change was made after the Sportster began using the Keihin carburetor so this would'​ve affected the L76 and E77 carbs. \\
  
 +===== Idle Transfer Ports =====
 +These are four holes (as viewed from the upper inside of the venture from the engine side). \\
 +  * Check that the ports are not gunked up and are free of obstructions.
 +  * Check that the Welch plug over the top of them isn't leaking. \\ It's good to remove any old sealer over the Welch plug and install some fresh. Read about [[techtalk:​ih:​carb01q#​welch_plug|Welch Plugs]] below.
 +  * If you've dunked the carb in carb cleaner, any sealant that was around the Welch plug would now be compromised and resealing is a must.
 ===== Jets ===== ===== Jets =====
 {{:​techtalk:​ih:​carb:​keihin_jets_by_billblack_-_cropped-annotated.jpg?​direct&​400|}} ((photo by billblack of the XLFORUM, cropped & annotated by Hippysmack http://​xlforum.net/​forums/​showthread.php?​p=4770495&​highlight=keihin+bowl#​post4770495)) \\ {{:​techtalk:​ih:​carb:​keihin_jets_by_billblack_-_cropped-annotated.jpg?​direct&​400|}} ((photo by billblack of the XLFORUM, cropped & annotated by Hippysmack http://​xlforum.net/​forums/​showthread.php?​p=4770495&​highlight=keihin+bowl#​post4770495)) \\
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 {{:​techtalk:​ih:​carb:​86_keihin_carb_repair_1_by_bustakneecap.jpg?​direct&​300|}} ((photo by bustakneecap of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​p=3864149)) {{:​techtalk:​ih:​carb:​86_keihin_carb_repair_2_by_bustakneecap.jpg?​direct&​300|}} ((photo by bustakneecap of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​p=3864149)) {{:​techtalk:​ih:​carb:​86_keihin_carb_repair_3_by_bustakneecap.jpg?​direct&​300|}} ((photo by bustakneecap of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​p=3864149)) \\ {{:​techtalk:​ih:​carb:​86_keihin_carb_repair_1_by_bustakneecap.jpg?​direct&​300|}} ((photo by bustakneecap of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​p=3864149)) {{:​techtalk:​ih:​carb:​86_keihin_carb_repair_2_by_bustakneecap.jpg?​direct&​300|}} ((photo by bustakneecap of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​p=3864149)) {{:​techtalk:​ih:​carb:​86_keihin_carb_repair_3_by_bustakneecap.jpg?​direct&​300|}} ((photo by bustakneecap of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​p=3864149)) \\
  
 +===== Choke Rod / Cable =====
 +
 +The old factory steel choke wire and the steel bracket works best. \\
 +When the bike backfires, it resists slapping the choke shut. \\
 +The cable type ones allow more flex at the bracket and subsequently the choke plate. \\
 ===== High Altitude Modification Kit ===== ===== High Altitude Modification Kit =====