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techtalk:evo:carb02 [2019/08/15 18:13]
ixl2relax [Change the Screws]
techtalk:evo:carb02 [2019/11/10 03:38] (current)
ixl2relax [Enrichener Function (Choke)]
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 [[:​techtalk:​menu|{{ ​ :​techtalk:​gototechnicalmenu.jpg|}}]] [[:​techtalk:​menu|{{ ​ :​techtalk:​gototechnicalmenu.jpg|}}]]
 ====== EVO: Carburetor, Intake Manifold & Exhaust ====== ====== EVO: Carburetor, Intake Manifold & Exhaust ======
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 ====== WORKING WITH CV40 CARBURETORS ====== ====== WORKING WITH CV40 CARBURETORS ======
  
-{{ techtalk:​evo:​carb:​cv40-carb-parts-id.jpg |Annotated by IXL2Relax at the XLForum}} +{{ techtalk:​evo:​carb:​cv40-carb-parts-id.jpg |Annotated by IXL2Relax at the XLForum }} || 
-{{ techtalk:​evo:​carb:​cv40-btm-covers.jpg?​400 |Annotated by IXL2Relax at the XLForum}}+{{ techtalk:​evo:​carb:​cv40-btm-covers.jpg?​400 |Annotated by IXL2Relax at the XLForum }} | {{ techtalk:​evo:​carb:​cv40-slidespringspider-sequence.jpg?​120 |Annotated by IXL2Relax at the XLForum }} |
  
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 When tuning, it is often less expensive to just buy the parts you actually need rather than tuning kits, which can get pricey. So planning ahead is a good idea. Know what you have before buying additional parts. When tuning, it is often less expensive to just buy the parts you actually need rather than tuning kits, which can get pricey. So planning ahead is a good idea. Know what you have before buying additional parts.
 +
 +==== Why Not Dynojet Kits? ====
  
 {{  :​techtalk:​evo:​carb:​cv40-needle-em-jets.jpg?​360| Photo by IXL2Relax at the XLForum}} {{  :​techtalk:​evo:​carb:​cv40-needle-em-jets.jpg?​360| Photo by IXL2Relax at the XLForum}}
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 While some people have had satisfactory results with the DJ kits, if you are having trouble getting a good tune on the carb, remove all DJ items and restore the carb to Keihin parts including buying another slide if it's been drilled. The stock parts are good quality and will provide excellent operation if the carb is tuned properly. ((the opinion of many on the XLForum)) While some people have had satisfactory results with the DJ kits, if you are having trouble getting a good tune on the carb, remove all DJ items and restore the carb to Keihin parts including buying another slide if it's been drilled. The stock parts are good quality and will provide excellent operation if the carb is tuned properly. ((the opinion of many on the XLForum))
 +
 +More info & links here: [[:​techtalk:​evo:​carb02c|SubDoc - Why Not Dynojet Kits?]]
  
 From the factory, there is a cap over the Idle Mixture Screw. This needs to be removed to make IMS adjustments during tuning. It does not need to be replaced when done, but the cap is available as HD P/N 28015-01 if you would like to replace it when done making changes.((IMS Cap - http://​xlforum.net/​forums/​showpost.php?​p=595622&​postcount=9)) From the factory, there is a cap over the Idle Mixture Screw. This needs to be removed to make IMS adjustments during tuning. It does not need to be replaced when done, but the cap is available as HD P/N 28015-01 if you would like to replace it when done making changes.((IMS Cap - http://​xlforum.net/​forums/​showpost.php?​p=595622&​postcount=9))
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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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 Replace the mounting screws used for the float bowl and for the diaphragm cover. They come with Japanese JIS metal head screws. These are similar to Phillips head screws but the JIS screwdriver has a more blunt nose and the Phillips screwdriver will not properly bite onto the JIS screw heads. Replace the mounting screws used for the float bowl and for the diaphragm cover. They come with Japanese JIS metal head screws. These are similar to Phillips head screws but the JIS screwdriver has a more blunt nose and the Phillips screwdriver will not properly bite onto the JIS screw heads.
  
-Replace these JIS screws with Stainless Hex Socket Head (Allen Head) Screws. Using lock washers & flat washers in stainless is also a good idea. Both sets of screws are 4mm Dia X .70 Thread Spacing. The socket head screws take a 3mm hex wrench.+Replace these JIS screws with Stainless ​**Hex Socket Head** (Allen Head) Screws. Using lock washers & flat washers in stainless is also a good idea. Both sets of screws are 4mm Dia X .70 Thread Spacing. The socket head screws take a 3mm hex wrench.
  
-You'll need (4) screws that are 16mm in length for the float bowl. Then you'll need (3) screws that are 16mm in length and (1) screw that is 20mm in length for the Diaphragm Cover. If you choose to use Button ​Head Socket Screws for the top cover, they use a 2.5mm hex wrench.+You'll need (4) screws that are 16mm in length for the float bowl. Then you'll need (3) screws that are 16mm in length and (1) screw that is 20mm in length for the Diaphragm Cover. If you choose to use **Button Socket ​Head** ​Screws for the top cover, they use a 2.5mm hex wrench.
  
 You can also replace the (3) Accelerator Pump screws with 4mm x 10mm long. ((rocketmangb & Folkie - http://​xlforum.net/​forums/​showthread.php?​t=635308)) You can also replace the (3) Accelerator Pump screws with 4mm x 10mm long. ((rocketmangb & Folkie - http://​xlforum.net/​forums/​showthread.php?​t=635308))
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-( 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]], [[http://​xlforum.net/​vbportal/​forums/​showthread.php?​t=165259|XLF Thread 4]] )
  
 As a reference, here are the OEM parts for the Carb Top Cover: As a reference, here are the OEM parts for the Carb Top Cover:
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 **Main Jet** - The Main Jet itself does not begin to limit fuel delivery to the carb operation until the vacuum slide is 75-90% wide open and the engine is revving. Until then, other parts & factors (such as the idle mixture screw, slow-jet and needle position in the needle jet) are controlling the fuel utilized by the carb. **Main Jet** - The Main Jet itself does not begin to limit fuel delivery to the carb operation until the vacuum slide is 75-90% wide open and the engine is revving. Until then, other parts & factors (such as the idle mixture screw, slow-jet and needle position in the needle jet) are controlling the fuel utilized by the carb.
  
-**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 tubewill 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 ​& Needle Jet** - The needle ​is a tapered, nail-like, rod that operates from the bottom of the slide into the needle jet. It does not affect the flow of fuel until the throttle plate opens sufficiently to create an active vacuum in the outer section of the venturi, which will lift the slide and move the needle in the needle jet. The fuel mix supplied ​thru the needle jet, by your selected needle and the emulsion tubewill 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.\\ The main jet, located at the bottom of the emulsion tube, is way below where the needle rides and has no relationship with what the needle does other than to create an eventual upper fuel limit at WOT. ((wedge of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=1820463&​page=9)) The needle rides in the needle jet which is the silver jet (hollow cylinder) that sticks up from the bottom of the throat of the carb and the needle moves up and down thru it during operation.\\ The tapered needle and needle jet together control fuel flow coming out of the emulsion tube into the throat. After the needle is almost up and out of the needle jet, then the main jet will become the limiting factor for the fuel flow at the wide open throttle position (WOT). Until the needle gets out of the way, the main jet is doing nothing to limit the needed fuel.\\ ( See this [[http://​xlforum.net/​forums/​showthread.php?​t=165259|XLForum Thread]] on needle dimensions) 
 + 
 +**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 (combining with) 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 use a compatible needle. It will also have an effect on the main jet size (at WOT) 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 at different throttle positions. 
  
 **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.
  
  
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 The CV40 has an Enrichener Circuit - It is labeled Choke on the knob, but that is a misnomer, because a choke refers to a plate that restricts the incoming air supply. The enrichener circuit actually provides a path for additional fuel to bypass the carb controls and be injected directly into the air flow at the rear of the carb venturi. The CV40 has an Enrichener Circuit - It is labeled Choke on the knob, but that is a misnomer, because a choke refers to a plate that restricts the incoming air supply. The enrichener circuit actually provides a path for additional fuel to bypass the carb controls and be injected directly into the air flow at the rear of the carb venturi.
  
-Typically, the enrichener should only be utilized when starting the engine when it is completely cold. Put the enrichener on, let the bike idle for 1-3 minutes, then ride off. Turn the enrichener off as soon as the engine warms up (perhaps within 3-5 miles of riding)...+Typically, the enrichener should only be utilized when starting the engine when it is completely cold. Put the enrichener on, let the bike idle for 1-3 minutes, then ride off. Turn the enrichener off as soon as the engine warms up (perhaps within 3-5 miles of riding)... ​\\
  
 +On a warm or hot engine, you may need to twist the throttle 1/8-1/4 turn to shoot some gas in before starting. \\
 +But do not use the enrichener unless the engine will not idle properly. \\
 +If the engine won't idle, pull the enrichener knob out enough to get it to idle, ride for a couple minutes and push the knob back in.
 +
 +Both excess use and insufficient use of the enrichener may cause poor performance,​ erratic idle, poor fuel economy and fouled plugs.
 +
 +{{ :​techtalk:​evo:​carb:​cv40-enrichener-knob.jpg?​300|}}
 The Enrichener Knob is a friction function device. When mounting the knob, do not overtighten the mounting nut. The resistance/​friction on the enrichener cable can be adjusted with the knurled nut. The Enrichener Knob is a friction function device. When mounting the knob, do not overtighten the mounting nut. The resistance/​friction on the enrichener cable can be adjusted with the knurled nut.
   * Loosen the hex nut & remove the cable from its mount.   * Loosen the hex nut & remove the cable from its mount.
   * Put an adj wrench on the flat part of the cable mounting sleeve.   * Put an adj wrench on the flat part of the cable mounting sleeve.
   * Carefully turn the knurled nut to loosen or tighten the tension until the knob stays pulled out on its own yet freely can be pushed back in with reasonable pressure.   * Carefully turn the knurled nut to loosen or tighten the tension until the knob stays pulled out on its own yet freely can be pushed back in with reasonable pressure.
-  * Remount the cable & tighten the hex nut. +  * Remount the cable with the lock washer behind the bracket ​& tighten the metal hex nut carefully (not over-tightening)
-Check that the knob moves freely in and out after mounting. Do not overtighten the hex mounting nut.+Check that the knob moves freely in and out after mounting.
  
 The fuel for the enrichener circuit is drawn thru a fixed jet in the float bowl. The air for the enrichener circuit is taken in thru the banana shaped inlet at the top of the carb face (see the face pic above). Sometimes when the enrichener cable is moved, or the carb has been taken off the manifold, the valve piston does not properly seat into its cavity on the carb. If that happens, additional attention must be given to properly reseating the enrichener valve piston. The fuel for the enrichener circuit is drawn thru a fixed jet in the float bowl. The air for the enrichener circuit is taken in thru the banana shaped inlet at the top of the carb face (see the face pic above). Sometimes when the enrichener cable is moved, or the carb has been taken off the manifold, the valve piston does not properly seat into its cavity on the carb. If that happens, additional attention must be given to properly reseating the enrichener valve piston.
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 You can read more in the REF Section on [[techtalk:​evo:​carb04#​exhaust_pipes_cams_-_power_or_reversion|Exhaust Pipes & Cams - Power or Reversion.]] ​ You can read more in the REF Section on [[techtalk:​evo:​carb04#​exhaust_pipes_cams_-_power_or_reversion|Exhaust Pipes & Cams - Power or Reversion.]] ​
 +
 +====== More on Jetting ======
 +Differences in pilot jets. \\
 +{{:​techtalk:​evo:​carb:​pilot_jet_chart_by_rocketmangb.png?​direct&​600|}} ((drawing by rocketmangb of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=1710330)) \\
 +