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techtalk:evo:carb02b [2019/01/29 10:57] ixl2relax |
techtalk:evo:carb02b [2024/01/02 22:02] (current) hippysmack |
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| ====== EVO: Carburetor, Intake Manifold & Exhaust - Sub-02B ====== | ====== EVO: Carburetor, Intake Manifold & Exhaust - Sub-02B ====== | ||
| - | ====== Carb Farts - XLF Thread ====== | + | ====== Carb Farts - XLForum Threads Summarized ====== |
| Carb Farts Discussion | Carb Farts Discussion | ||
| - | http://xlforum.net/forums/showthread.php?t=33327 | + | https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-intake-and-exhaust/sportster-motorcycle-air-intake-carburetor-efi-fuel-and-exhaust/20117-carb-farts-forever?t=33327 |
| **All posts by Chris Hajer unless otherwise noted.** | **All posts by Chris Hajer unless otherwise noted.** | ||
| Line 93: | Line 93: | ||
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\\ | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\\ | ||
| - | http://xlforum.net/forums/showthread.php?t=30561 | + | https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-intake-and-exhaust/sportster-motorcycle-air-intake-carburetor-efi-fuel-and-exhaust/18344-cv-carb-mod-to-reduce-carb-farts?t=30561 |
| - | Post#31 - Stevo\\ | + | Post#31 - Comments from Stevo\\ |
| A carb fart is basicly caused by a lean condition... often from not having enough fuel when cold or from lack of vacuum from blipping or opening the throttle too quickly.... | A carb fart is basicly caused by a lean condition... often from not having enough fuel when cold or from lack of vacuum from blipping or opening the throttle too quickly.... | ||
| A mikuni will do it if you open it too quickly... | A mikuni will do it if you open it too quickly... | ||
| - | Too much air is entering the intake plenum for the amount of fuel for those particualr rengine requirements at that point in time.. ie : it's too lean.. | + | Too much air is entering the intake plenum for the amount of fuel for those particular engine requirements at that point in time.. ie : it's too lean.. |
| A fart thru the exhaust or flat sound is usually from a rich condition... | A fart thru the exhaust or flat sound is usually from a rich condition... | ||
| Line 114: | Line 114: | ||
| The CV carb has an annoying habit of spitting back through the air cleaner. This is sometimes called a carb fart, lean misfire, spit, cough, hiccup, backfire, etc. It is a characteristic of the carb. When you twist the throttle, you are opening a butterfly valve in the carb, and velocity of the air flowing through it drops. The slide responds by dropping down to make the venturi smaller in an attempt to keep the velocity "constant" (hence 'CV', constant velocity, carb.) It doesn't always work. Sometimes there is a lag between the time the butterfly opens and the slide drops. In this instant, the mixture goes lean and there is a lean misfire. The accelerator pump tries to compensate, but it's not always successful. Sometimes the throttle movement is not enough to trigger a shot of fuel from the accelerator pump. | The CV carb has an annoying habit of spitting back through the air cleaner. This is sometimes called a carb fart, lean misfire, spit, cough, hiccup, backfire, etc. It is a characteristic of the carb. When you twist the throttle, you are opening a butterfly valve in the carb, and velocity of the air flowing through it drops. The slide responds by dropping down to make the venturi smaller in an attempt to keep the velocity "constant" (hence 'CV', constant velocity, carb.) It doesn't always work. Sometimes there is a lag between the time the butterfly opens and the slide drops. In this instant, the mixture goes lean and there is a lean misfire. The accelerator pump tries to compensate, but it's not always successful. Sometimes the throttle movement is not enough to trigger a shot of fuel from the accelerator pump. | ||
| - | In their quest to eliminate the carb farts completely, some people over-jet the idle circuit. If your bike needs NO enrichener to start when it's cold, and it NEVER has a lean misfire through the carb, it is probably too rich. Rather than over-jetting the idle circuit to eliminate the carb farts completely, I have used the following mod with a mixture screw adjustment and no pilot jet change with good results on the half-dozen or so problem bikes I ran across. | + | In their quest to eliminate the carb farts completely, some people over-jet the idle circuit. If your bike needs NO enrichener to start when it's cold, and it NEVER has a lean misfire through the carb, it is probably too rich. |
| + | |||
| + | Rather than over-jetting the idle circuit to eliminate the carb farts completely, I have used the following mod with a mixture screw adjustment and no pilot jet change with good results on the half-dozen or so problem bikes I ran across. | ||
| Here's the mod (not for the squeamish):\\ | Here's the mod (not for the squeamish):\\ | ||
| - | http://xlforum.net/forums/showthread.php?t=30561 | + | https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-intake-and-exhaust/sportster-motorcycle-air-intake-carburetor-efi-fuel-and-exhaust/18344-cv-carb-mod-to-reduce-carb-farts?t=30561 |
| **__NOTE: The modification listed in the above referenced thread is a PERMANENT MODIFICATION!__**\\ | **__NOTE: The modification listed in the above referenced thread is a PERMANENT MODIFICATION!__**\\ | ||
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| Idle Drop Method\\ | Idle Drop Method\\ | ||
| - | http://xlforum.net/forums/showthread.php?t=31262 | + | https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-intake-and-exhaust/sportster-motorcycle-air-intake-carburetor-efi-fuel-and-exhaust/18838-the-idle-drop-method-of-adjusting-the-cv-carb-idle-mixture?t=31262 |
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