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techtalk:ih:carb01 [2020/06/22 01:22]
hippysmack [Sub Documents]
techtalk:ih:carb01 [2021/03/25 03:02] (current)
hippysmack [Sub Documents]
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 ^Serial Number^Main Jet^ ^Serial Number^Main Jet^
 |27160-66B ((rivethog of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=757993&​page=2)) \\ Big Twin|  | |27160-66B ((rivethog of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=757993&​page=2)) \\ Big Twin|  |
-|27162-66B((Shop Dope Vol 4 Service Bulletin No 571 May 21, 1968))| ​   | +|27162-66B((Shop Dope Vol 4 Service Bulletin No 571 May 21, 1968)) ​\\ Sportster|    | 
-|27162-66C((HD Sportster Parts Catalog pg B11-1 (99451-78B) ))|0.053",​ 0.055",​ 0.059",​ 0.057",​ 0.061",​ 0.063"​((HD Sportster Parts Catalog pg B11-1 (99451-78B) ))|+|27162-66C((HD Sportster Parts Catalog pg B11-1 (99451-78B) )) \\ Sportster|0.053",​ 0.055",​ 0.059",​ 0.057",​ 0.061",​ 0.063"​((HD Sportster Parts Catalog pg B11-1 (99451-78B) ))|
 |27155-66RA (XLR)|(27823-66R)| |27155-66RA (XLR)|(27823-66R)|
 |27155-70R (XR)|(27823-66R)| |27155-70R (XR)|(27823-66R)|
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 ^Sportster Model^Year \\ Carb Used^HD Part Number^Flange / \\ Casting \\ Number^ ​ Main Jet \\ Size  ^Low Speed \\ Jet Size^Initial Mixture \\ screw setting^Accel Pump \\ spring position^ ^Sportster Model^Year \\ Carb Used^HD Part Number^Flange / \\ Casting \\ Number^ ​ Main Jet \\ Size  ^Low Speed \\ Jet Size^Initial Mixture \\ screw setting^Accel Pump \\ spring position^
-|XLH, XLCH|Late 1976|27153-76((HD Sportster Parts Catalog XLH/XLCH 99451-78B))|B50A ((HD Service Bulletin #M-713 dated June 10, 1977))|(140 std) ((HD Service Bulletin #M713 dated June 10, 1977)) \\ Optional jets ((HD Parts and Accessories Bulletin dated February 8, 1977)) ​ \\ - 130, 135, 145, 150 \\ 155, 160, 165, 170, 175((HD Sportster Parts Catalog XLH/XLCH 99451-78B))|100|7/​8 ((HD Service Bulletin #M713 dated June 10, 1977))|Upper ((HD Service Bulletin #M713 dated June 10, 1977))|+|XLH, XLCH|Late 1976|27153-76((HD Sportster Parts Catalog XLH/XLCH 99451-78B))|B50A ((HD Service Bulletin #M-713 dated June 10, 1977))|(140 std) ((HD Service Bulletin #M-713 dated June 10, 1977)) \\ Optional jets ((HD Parts and Accessories Bulletin dated February 8, 1977)) ​ \\ - 130, 135, 145, 150 \\ 155, 160, 165, 170, 175((HD Sportster Parts Catalog XLH/XLCH 99451-78B))|100|7/​8 ((HD Service Bulletin #M713 dated June 10, 1977))|Upper ((HD Service Bulletin #M-713 dated June 10, 1977))|
 |XLH, XLCH, XLT|1977-1978 |27153-77 ((HD Sportster Parts Catalog XLH/XLCH 99451-78B))|B50B ((HD Service Bulletin #M-713 dated June 10, 1977)) \\ B50C |(160 std) ((1954-1977 HD Sportster Parts Supplement pg 2)) (165 std) ((HD Service Bulletin #M713 dated June 10, 1977)) \\ Optional jets ((HD Parts and Accessories Bulletin dated February 8, 1977)) ​ \\ - 130, 135, 145, 150 \\ 155, 160, 165, 170, 175((HD Sportster Parts Catalog XLH/XLCH 99451-78B))|75|1-1/​4 ((HD Service Bulletin #M713 dated June 10, 1977))|Center ((HD Service Bulletin #M713 dated June 10, 1977))| |XLH, XLCH, XLT|1977-1978 |27153-77 ((HD Sportster Parts Catalog XLH/XLCH 99451-78B))|B50B ((HD Service Bulletin #M-713 dated June 10, 1977)) \\ B50C |(160 std) ((1954-1977 HD Sportster Parts Supplement pg 2)) (165 std) ((HD Service Bulletin #M713 dated June 10, 1977)) \\ Optional jets ((HD Parts and Accessories Bulletin dated February 8, 1977)) ​ \\ - 130, 135, 145, 150 \\ 155, 160, 165, 170, 175((HD Sportster Parts Catalog XLH/XLCH 99451-78B))|75|1-1/​4 ((HD Service Bulletin #M713 dated June 10, 1977))|Center ((HD Service Bulletin #M713 dated June 10, 1977))|
 |XL, XLCH, XLS |1979|27469-78 ((1979 Harley Davidson Sportster Parts Catalog)) \\ 27469-78A ((1980 HD Sportster Parts Catalog -80 pg 17))|B83A \\ B83B|165 \\ 160 - above 4000' ((HD Service Buletin #M-730 dated June 15, 1978 - Instruction Sheet pg 2))|65 ((1979 Harley Davidson Sportster Parts Catalog))| ​ |XL, XLCH, XLS |1979|27469-78 ((1979 Harley Davidson Sportster Parts Catalog)) \\ 27469-78A ((1980 HD Sportster Parts Catalog -80 pg 17))|B83A \\ B83B|165 \\ 160 - above 4000' ((HD Service Buletin #M-730 dated June 15, 1978 - Instruction Sheet pg 2))|65 ((1979 Harley Davidson Sportster Parts Catalog))| ​
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 ^Other HD Model^Year \\ Carb Used^Serial Number^Flange / \\ Casting \\ Number^ ​ Main Jet \\ Size  ^Low Speed \\ Jet Size^Initial Mixture \\ screw setting^Accel Pump \\ spring position^ ^Other HD Model^Year \\ Carb Used^Serial Number^Flange / \\ Casting \\ Number^ ​ Main Jet \\ Size  ^Low Speed \\ Jet Size^Initial Mixture \\ screw setting^Accel Pump \\ spring position^
-|All FX|76|27155-76| 860A ((Hd TSB #M713 dated June 10, 1977)) \\ 860B |185 ((Hd TSB #M713 dated June 10, 1977))|100|7/​8|center|+|All FX|76|27155-76| 860A ((Hd TSB #M-713 dated June 10, 1977)) \\ 860B |185 ((Hd TSB #M713 dated June 10, 1977))|100|7/​8|center|
 |All FL|76-E77|:::​|:::​|:::​|:::​|:::​|:::​| |All FL|76-E77|:::​|:::​|:::​|:::​|:::​|:::​|
 |The (860B) had the longer 59.5mm accelerator pump rod. ((1966-1984 HD FL Parts Catalog (99456-84B) pg 33))|||||||| |The (860B) had the longer 59.5mm accelerator pump rod. ((1966-1984 HD FL Parts Catalog (99456-84B) pg 33))||||||||
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   * The original idle mixture setting for E76 Keihin carbs was 1-1/2 turns out and adjust from there. ((TSB #694 dated November 7, 1975)) \\ In December of 1976, that was changed to 7-8 turns out for FL and FX models. ((HD TSB #M-707 dated December 1, 1976)) \\ In June of 1977, L77-up FL and FX models were changed back to 1-1/2 turns out with earlier models remaining at 7/8 turns.   * The original idle mixture setting for E76 Keihin carbs was 1-1/2 turns out and adjust from there. ((TSB #694 dated November 7, 1975)) \\ In December of 1976, that was changed to 7-8 turns out for FL and FX models. ((HD TSB #M-707 dated December 1, 1976)) \\ In June of 1977, L77-up FL and FX models were changed back to 1-1/2 turns out with earlier models remaining at 7/8 turns.
  
-===== Swapping to a Keihin CV Carb =====+====== Boiling Gas ====== 
 +Gas getting to the boiling point can happen for several reasons. \\ 
 +Having the gas line resting against the engine, the float set too low and others will also attribute to boiling gas. \\ 
 +The problem from hot gas is a vapor lock if the gasoline is heated to the point where it vaporizes before it reaches the intake. ((KWJams of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=496913)) \\ 
 + 
 +**A lean bike will run hot**: \\ 
 +Make sure the intake seals really well and make sure they'​re not leaking. ((FourCams of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=496913)) \\  
 + 
 +**Engine heat transferring thru the carb**: \\ 
 +On BTs, an erratic idle condition can happen due to fuel vaporization in slow moving traffic or at high ambient temperatures. \\ 
 +The engine temperature may rise to the point where it heats the carburetor enough to boil the fuel. \\ 
 +When this happens, the engine can idle erratically and stop. \\ 
 + 
 +You may be able to look inside your gas tank after the bike has been sitting for about 15 minutes and see gas boil inside the tank. ((MDT of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=496913)) \\ 
 +While your engine is running, the air going through the carb, cools the carb. \\ 
 +But when you shut off the engine, the heat from your heads and cylinders transfers into your carb. With nothing to cool your carb, you can hear your vent gurgling. \\ 
 +If your carb vent is plugged, it can push gas from your bowl through your main jet, right into your intake. 
 +You can get fiber insulators that will help lower the heat transfer to your carb. \\ 
 +The fix is to install a phenolic spacer between the carb and the manifold. \\ 
 +See [[techtalk:​ih:​carb01#​heat_spacer_insulator_block|Heat Spacer/​Insulator Block]] below. \\ 
 + 
 +**Fuel line touching the engine**: \\ 
 +Fuel line routing options are limited by the design. Keep the fuel line away from touching the cylinders/​heads. \\ 
 +The air flow between them should be adequate to keep the fuel cool as long as the fuel line is not touching a heat source. \\ 
 +   
 +Below, a fuel boiling problem was found in a 77 XLCH by XLF member, gemeinschaft. \\ 
 +<​blockquote>​I went for a ride yesterday, it was great. Then, I smelled gasoline. I noticed gas coming out of the carb after I stopped. ((gemeinschaft of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=496913&​page=3)) \\ 
 +I double checked and yes, the petcock was turned off. I looked at the fuel filter and there were bubbles as the gasoline was at a rolling boil (in the clear tube fuel filter). \\ 
 +I backed off and waited for a while and pretty soon it all evaporated. \\ 
 +My petcock is on the left side and it runs down by the horn in between the two cylinders. (Talk about a heat source). \\ 
 +The fuel line literally touches the fins of the rear cylinder and then goes back up to the carb. \\ </​blockquote>​ 
 + 
 +|  This fuel line is in the lower "​V"​ and touching the cylinders. Bubbles were found in the filter. ((photos by gemeinschaft of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=496913&​page=3)) ​  || 
 +|{{:​techtalk:​ih:​carb:​boiling_gas_1_by_gemeinschaft.jpg?​direct&​300|}}|{{:​techtalk:​ih:​carb:​boiling_gas_2_by_gemeinschaft.jpg?​direct&​300|}}| 
 + 
 +**Possible fixes to keep the fuel line away from the engine**: \\ 
 +  * You can route the line so it avoids the heads and cylinders as best you can. ((Moon Wolf of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=766794)) \\ You can use a longer or shorter line to allow you some flexibility in routing. \\ You want a steady downward slope from the petcock to the carb eunning gravity type petcocks. 
 +  * Use fuel line with braided stainless-steel sheathing to protect the rubber hose from heat. \\ If your fuel hose melts and spills gas onto the motor, you won't soon forget it. 
 +  * Slip a length of coiled wire (or a spring) over the braided fuel line where it goes between the jugs. \\ This has been done on everything from hot rods to airplanes for longer than anyone can remember. 
 +  * You can take the spiral wire from a paper notebook and stretch it some and run the fuel line through it. \\ You just want to keep it from touching the cylinders/​heads. ((jharback of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=766794)) 
 +  * Use clothes pins on the fuel line to create some space for the line. 
 + 
 +|  Clothes pins attached to fuel line for separation. ((photo by JonesL of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​p=5840490#​post5840490)) ​ | 
 +|{{:​techtalk:​ih:​carb:​clothes_pin_separation_for_gas_hose_by_jonesl.jpg?​direct&​300|}}| 
 + 
 +====== Heat Spacer / Insulator Block ====== 
 + 
 +**The insulating block was not known to be suggested for use on Sportster Bendix or Keihin butterfly carbs by the MoCo**. \\ 
 +In December of 1976, insulating block (27412-57) was suggested to use on 76 and later FL and FX models (one block on FX and two blocks on FL models). ((HD TSB #M-707 dated December 1, 1976)) \\ 
 +This was suggested to eliminate erratic idle due to fuel vaporization in slow moving traffic or at high ambient temperatures. \\ 
 +The engine temperature may rise to the point where it heats the carburetor enough to boil the fuel. \\ 
 +When this happens, the engine can idle erratically and stop. To prevent this, place the insulating block(s) between the engine and carburetor. \\ 
 +[[techtalk:​miscres:​miscres05#​tsb_700-749|Click here to view the TSB page in the Sportsterpedia]]. Click on the "​Y"​ next to M-707 to view download the PDF. \\ 
 + 
 +In August of 1977, a Service Bulletin was issued regarding the use of a new spacer block (29250-78A) on 1977→ 1200CC engines. ((HD TSB #M-715 dated August 12, 1977)) \\ 
 +The bulletin addresses proper installation for better sealing of the carb to A/C and carb/​insulator block/​manifold seal. \\ 
 +[[techtalk:​miscres:​miscres05#​tsb_700-749|Click here to view the TSB page in the Sportsterpedia]]. Click on the "​Y"​ next to M-715 to view download the PDF. \\ 
 +This kit was also suggested for installation of the spacer block. \\ 
 +|PART #​|DESCRIPTION|QUANTITY|REPLACES| 
 +|7739|LOCK NUT \\ 5/​16"​-18 x 11/32" X 1/2" Hex|  2  |  7725  | 
 +|5895|INSULATING SPACER| ​ 1  |  -  | 
 +|24820-78|STUD \\ 5/​16"​-18 x 5/​16-18| ​ 2  |  24818-52 ​ | 
 +|27077-78|GASKET| ​ 2  |  -  | 
 + 
 +In April of 1984, a Service Bulletin was issued a gasket (27023-71) was added between the carb and insulator block on 1340cc engines assembled in February, 1984. \\ 
 +On earlier 1340'​s,​ if an air leak was found or suspected between the carburetor and insulator block, the gasket was to be installed. \\ 
 +[[techtalk:​miscres:​miscres05#​tsb_700-749|Click here to view the TSB page in the Sportsterpedia]]. Click on the "​Y"​ next to M-888 to view download the PDF. \\ 
 + 
 +Some Sportster owners say they have never needed them and others use them regularly. \\ 
 +**Argument for using the spacer**: \\ 
 +((photo by Robicycle of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=1663198&​highlight=keihin+bowl)) ((photo by Hopper of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=276157&​page=3)) {{ :​techtalk:​ih:​carb:​keihin_butterfly_carb_6_by_hopper.jpg?​direct&​300|}} \\ {{ :​techtalk:​ih:​carb:​keihin_butterfly_carb_4_by_robicycle.jpg?​direct&​300|}} \\ 
 +The Phenolic fiber spacer helps with hot idle or starting problems. One infuriatingly simple thing that affects idle, starting and carb farts when your engine is hot, is this phenolic fiber spacer. ((Hopper of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=276157&​page=3)) It's between the carb and manifold, which some models had and others did not. It stops engine heat from flowing into the carb. If your model doesn'​t have one of these stock, you can cut one out of a sheet of fiber about 3/16" thick. JP Cycles or others sell one that is a bit thicker and might work even better. There should be a gasket on each side of the spacer while still using the rubber O-ring on the carb flange. Of course, make sure both the carb flange and the manifold are filed nice and flat with a 10-inch flat file first. Without it, your carb can get too hot to touch within minutes of the bike being parked with a hot engine. Even the air filter gets hot. There is a lot of heat flowing from the heads, up the manifold and into the carb which makes it hard to start and idle rough. The heat vaporizes the fuel in the float bowl and it can boil and come out the overflow tube at the bottom of the float bowl. This also means the tiny amount of fuel trying to go through the idle adjuster screw and into the carb throat can also vaporize. Fuel going into the engine needs to be tiny globules of liquid fuel, not vapor. Putting a heat-blocking spacer on is really worth the effort if you ride a lot in city traffic. (where idling at the lights will allow heat to flow into the carb while there is no cooling wind) With a kick only XLCH, the easier hot starting is a Godsend. \\ 
 + 
 +**Here are some part numbers for the different insulator blocks used on 4 stroke Harleys**. \\ 
 +There is no known insulator block that was factory installed on a Bendix Carb. \\ 
 + 
 +  * 27412-57 for 57-65 XL FL, FX. (Linkert) 
 +  * 27015-66 for XLH 66-71.XLCH '​66;​70-71 (Tillotson) 
 +  * 27012-67 (has 1 longer stud) 66-69 XLCH67-70 BTs (Tillotson) 
 +  * 29250-78 for 76-89 BTs (Keihin butterfly) 
 +  * 29250-78A for 78-E84 FL,FLH and Late 78-E84 FLT and 80-85 FXR (Keihin butterfly) 
 +  * 27003-86 for 86-87 XL (Keihin butterfly) 
 +  * 27003-86A for 86-87 XL (Keihin butterfly) 
 +  * 29266-86 plastic, for 86-87 XL (Keihin butterfly). 
 +====== Swapping to a Keihin CV Carb ======
 See [[techtalk:​ref:​carb09|Ironhead - Installing a Keihin CV Carb]] in the REF section of the Sportsterpedia. \\ See [[techtalk:​ref:​carb09|Ironhead - Installing a Keihin CV Carb]] in the REF section of the Sportsterpedia. \\