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techtalk:evo:carb02 [2019/06/14 21:06]
ixl2relax [Before Tuning - Collect Your Information]
techtalk:evo:carb02 [2019/09/09 23:20] (current)
hippysmack [The Idle/Transfer Ports Operation & Tuning]
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 To remove the IMS cap, carefully drill a small hole in the center of the cap (barely enough to make a hole). Be extremely careful not to overdrill into the cap because you will damage the screw that is behind the cap. Now, carefully twist in a sheetmetal screw about one thread, then pull on the screw to remove the cap. To remove the IMS cap, carefully drill a small hole in the center of the cap (barely enough to make a hole). Be extremely careful not to overdrill into the cap because you will damage the screw that is behind the cap. Now, carefully twist in a sheetmetal screw about one thread, then pull on the screw to remove the cap.
  
-An aftermarket kit (like E-Z-just) can be purchased with an extended screw head for hand tuning. It comes with the "​packing"​ 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))).+An aftermarket kit (like E-Z-just) can be purchased with an extended screw head for hand tuning. It comes with the "​packing"​ 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)) ((a/f screw packing photo by tchuck of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=183642)).
  
 **Checklist Of What You Have** - In order for others to provide quality advice, it is important that you know and can provide quality information about the build of your bike. Here's a list of important information for you to know and provide for TUNING of the CV carburetored EVOs (1986-2006):​ **Checklist Of What You Have** - In order for others to provide quality advice, it is important that you know and can provide quality information about the build of your bike. Here's a list of important information for you to know and provide for TUNING of the CV carburetored EVOs (1986-2006):​
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 1ea - 4mm x 20mm x .70TPI for Top Diaphragm Cover at Throttle Bracket\\ 1ea - 4mm x 20mm x .70TPI for Top Diaphragm Cover at Throttle Bracket\\
 3ea - 4mm x 10mm x .70TPI for Accelerator Pump\\ 3ea - 4mm x 10mm x .70TPI for Accelerator Pump\\
 +Hex Head bolts use 3.0mm hex wrench\\
 +Button Head bolts use 2.5mm hex wrench
 +
  
 ( Also see: [[http://​xlforum.net/​vbportal/​forums/​showthread.php?​t=167074|XLF Thread 1]], [[http://​xlforum.net/​vbportal/​forums/​showthread.php?​t=1966443|XLF Thread 2]] & [[http://​xlforum.net/​vbportal/​forums/​showthread.php?​t=1792262|XLF Thread 3]] ) ( Also see: [[http://​xlforum.net/​vbportal/​forums/​showthread.php?​t=167074|XLF Thread 1]], [[http://​xlforum.net/​vbportal/​forums/​showthread.php?​t=1966443|XLF Thread 2]] & [[http://​xlforum.net/​vbportal/​forums/​showthread.php?​t=1792262|XLF Thread 3]] )
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 **Needle** - The needle does not begin to supply fuel until the throttle plate opens sufficiently to create an active vacuum in the outer section of the venturi. The fuel mix supplied by your selected needle (and the emulsion tube) will combine with the transfer fuel mix of the slow jet as the carb operation moves out of the transfer period into the mid-range of the throttle/​slide function. **Needle** - The needle does not begin to supply fuel until the throttle plate opens sufficiently to create an active vacuum in the outer section of the venturi. The fuel mix supplied by your selected needle (and the emulsion tube) will combine with the transfer fuel mix of the slow jet as the carb operation moves out of the transfer period into the mid-range of the throttle/​slide function.
 +
 +**Emulsion Tubes** ((stevo of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=2876)):​ - As the throttle plate is opened further the main circuit comes into play. Fuel enters the bottom of the emulsion tube thru the main jet. Air enters thru the main air bleed jet in the front of the carb. The air and fuel are mixed into an emulsion in the emulsion tube before it passes up the tube past the needle jet and needle into the carb venturi and down the intake chasing after the idle circuit fuel. The size, number and position of the holes in the emulsion tube effect the fuel delivery. More holes = more air = leaner mixture. More holes at the top = leaner mixture at low speeds. More holes at the bottom = leaner mixture at high speeds. If you change emulsion tubes you need to put a matching needle in and it will also have an effect on the main jet size and quite often the pilot circuit thru the just off idle response. Needles, needle jet, emulsion tube (size, position and amount of holes) main air bleed size and main jet are all closely linked. Changing one can affect the others and all have an affect on the fuel delivery to differing amount.
 +
  
 **Throttle Plate** - To assure the throttle plate is capable of closing completely, back out the idle set screw (on the side of the carb near the throttle cable cam) so that it is not limiting the closing of the throttle plate. Carefully loosen the two throttle plate mounting screws, slightly. After the throttle plate is fully closed and has centered itself in the venturi, retighten the two mounting screws (don't overtighten & strip the threads). Make sure the throttle plate rotates smoothly with the throttle cable cam. Set the position of the throttle plate, with the idle set screw, so that the bottom edge of the plate is closed just past the transfer port holes and is thus located between the single idle port hole and the multiple holes of the transfer ports. (If by chance, for any reason, you have the throttle plate completely off, be aware that there is right & wrong way to reinstall it. Be sure the plate is remounted with the right orientation because the top & bottom have an angled edge that needs to properly meet the carb venturi.) **Throttle Plate** - To assure the throttle plate is capable of closing completely, back out the idle set screw (on the side of the carb near the throttle cable cam) so that it is not limiting the closing of the throttle plate. Carefully loosen the two throttle plate mounting screws, slightly. After the throttle plate is fully closed and has centered itself in the venturi, retighten the two mounting screws (don't overtighten & strip the threads). Make sure the throttle plate rotates smoothly with the throttle cable cam. Set the position of the throttle plate, with the idle set screw, so that the bottom edge of the plate is closed just past the transfer port holes and is thus located between the single idle port hole and the multiple holes of the transfer ports. (If by chance, for any reason, you have the throttle plate completely off, be aware that there is right & wrong way to reinstall it. Be sure the plate is remounted with the right orientation because the top & bottom have an angled edge that needs to properly meet the carb venturi.)
  
 {{ :​techtalk:​evo:​carb:​cv40-imscap-drillbit.jpg?​200|}} {{ :​techtalk:​evo:​carb:​cv40-imscap-drillbit.jpg?​200|}}
-**IMS Cap** - From the factory, the cavity for the Idle Mixture Screw (IMS) is covered with a small cap. (Note from the service manual: Adjusting mixture setting by procedures other than those specified in the manual may be in violation of local regulations.) The following procedures are not specified in the manual. To remove the cap and gain access to the IMS, use a small drill bit to create a hole in the cap. Use several layers of tape on the drill bit to limit the depth the bit can penetrate the cap. If you pop thru the cap too deep with the bit, you may damage the internal screw head - Be Careful. Once your cap has a hole in it, CAREFULLY thread a self-tapping screw (blunt nose) into the hole JUST ENOUGH to capture the cap & pull it out of the IMS cavity.+**IMS Cap** - From the factory, the cavity for the Idle Mixture Screw (IMS) is covered with a small cap. (Note from the service manual: Adjusting mixture setting by procedures other than those specified in the manual may be in violation of local regulations.) The following procedures are not specified in the manual. To remove the cap and gain access to the IMS, use a small drill bit to create a hole in the cap. Use several layers of tape on the drill bit to limit the depth the bit can penetrate the cap. If you pop thru the cap too deep with the bit, you may damage the internal screw head - Be Careful. Once your cap has a hole in it, CAREFULLY thread a self-tapping screw (blunt nose) into the hole JUST ENOUGH to capture the cap & pull it out of the IMS cavity. ​((photo by cantolina of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=14949))
  
 {{:​techtalk:​evo:​carb:​cv40-idletransferports.jpg|}} ​    ​{{:​techtalk:​evo:​carb:​cv40-idletransfer-diagram.jpg|}} {{:​techtalk:​evo:​carb:​cv40-idletransferports.jpg|}} ​    ​{{:​techtalk:​evo:​carb:​cv40-idletransfer-diagram.jpg|}}
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 ((http://​xlforum.net/​forums/​showthread.php?​postid=5342857#​post5342857)) ((http://​xlforum.net/​forums/​showthread.php?​postid=5342857#​post5342857))
- 
-\\ 
- 
- 
- 
-===== Simply Rebuilding / Refreshing The CV Carb ===== 
- 
-\\ 
- 
- 
-==== Disassembly ==== 
- 
-  *  
-  *  
- 
-==== Cleaning & Inspecting ==== 
-  * Make sure to take everything apart, jets, needle, accel pump, all rubber components especially. 
-  * Examine all parts for excessive wear, damage, distortion, etc. 
-  * Cleaning solutions/​sprays vary based upon your location, needs, budget, preferences and quality. Here are some ideas: ​ 
-     * An overnight soak in a solution of Pinesol and water followed up with a good brush down with a toothbrush then rinse and air dry. ((http://​www.hotrodders.com/​forum/​pinesol-really-does-clean-carburetors-amazingly-pics-inside-248810.html)) 
-     * A 20 minute soak in a gallon of Gunk (or other) Carburetor Cleaner that has a basket inside for small parts and lowers in the can with a handle, rinse, air dry, use. 
-     * An aerosol spray carb cleaner will also work but may not loosen all of the build up in the jets or orifices in the carb body if they'​re not directly sprayed through. ​ 
-  * Blow out all holes, jets and orifices thoroughly with forced air after cleaning. 
-  ​ 
-==== Replacement Parts ==== 
- 
-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 rebuild kits are usually less than $20 and include: 
-  * Carb-to-Manifold Seal 
-  * Carb-to-Air Cleaner Gasket 
-  * Float Bowl Gasket/​O-ring 
-  * New Float Needle 
-  * New Accelerator Pump Diaphragm & Spring 
-  * Some Misc Parts/Seals 
- 
- 
-==== Assembly ==== 
-  * Do not lubricate the enrichment cable (misnamed Choke) on CV Carburetors - tension is needed. ((1998 FSM Pg 1-1)) 
-  *  
- 
-\\ 
- 
- 
-Add'l Info & Pics - \\ 
- 
-Accelerator Nozzle, Check Valve, Float Seat - http://​xlforum.net/​forums/​showthread.php?​t=1624208\\ 
-Accelerator Nozzle & Check Valve - http://​xlforum.net/​forums/​showthread.php?​t=1775068\\ 
- 
  
 \\ \\
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 | 2004-2006 - 883 | 27777-04 | 27260-00 | 27577-92 | ::: | | 2004-2006 - 883 | 27777-04 | 27260-00 | 27577-92 | ::: |
 | 2004-2006 - 1200 | 27256-01 | 27260-00 | 27577-92 | ::: | | 2004-2006 - 1200 | 27256-01 | 27260-00 | 27577-92 | ::: |
-{{:​techtalk:​evo:​carb:​cv40-floatbowl-0304-ap.jpg?​600|}} ((Discussion & pics from Robistro on the XLForum at http://​xlforum.net/​forums/​showthread.php?​t=2070191))+{{:​techtalk:​evo:​carb:​cv40-floatbowl-0304-ap.jpg?​600|}} ((Discussion & pics from Robistro on the XLForum at http://​xlforum.net/​forums/​showthread.php?​t=2070191)) ​\\  
 + 
 +{{:​techtalk:​evo:​carb:​xl1200s_keihin_cv_float_bowl_-_49_state_by_hippysmack.jpg?​direct&​300|}} ((photo by Hippysmack)) \\ 
 + 
 +There are 3 types checks for the accel pump jets: ball, needle and calibrated orifice-(no check at all). ((buster of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=2024981)) \\ 
 +Older units had change-able jets to calibrate the squirt, newer ones are fixed and can only adjust the timing of the squirt. \\
  
 {{techtalk:​evo:​carb:​cv40-accelpump-ckvalve.jpg |Annotated by IXL2Relax at the XLForum}} {{techtalk:​evo:​carb:​cv40-accelpump-ckvalve.jpg |Annotated by IXL2Relax at the XLForum}}
 +
 +\\
 +
 +{{:​techtalk:​evo:​carb:​91_keihin_cv_accelerator_pump_jet_by_blackbikedave.jpg?​direct&​400|}} ((photos by BlackBikeDave,​ cropped-annotated by Hippysmack http://​xlforum.net/​forums/​showthread.php?​t=2024981)) \\
 +
 +**Float Bowl Overflow** - Notice the Overflow Tube in the above picture. The channel for the escape of that float bowl overflow was also used for a float bowl drain. This is shown at the beginning of this page on the picture of the bottom of the float bowl. This overflow was a safeguard against the failure of the float bowl valve from not closing. Should that happen, the fuel would be expelled onto the ground rather than being pushed into the intake manifold and filling the cylinders (and eventually the crankcase) with raw fuel.
 +
 +Note, however, that the 1998-2003 1200S carbs have no float bowl overflow tube protection. They also have no drain plug & hose to empty float chamber for off riding season or extended storage.