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techtalk:ref:engmech05 [2020/10/06 21:31]
hippysmack [Sub Documents]
techtalk:ref:engmech05 [2023/12/21 16:38] (current)
hippysmack [OEM Breathe Bolts]
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   * [[techtalk:​ref:​engmech05i|79-85 Breather Vent Mod - Adding a Secondary Vent Hose at 6:00 Position]]   * [[techtalk:​ref:​engmech05i|79-85 Breather Vent Mod - Adding a Secondary Vent Hose at 6:00 Position]]
   * [[techtalk:​ref:​engmech05j|Aftermarket Breather Valves]]   * [[techtalk:​ref:​engmech05j|Aftermarket Breather Valves]]
-  * Related articles in the Sportsterpedia.+  ​* [[techtalk:​ref:​engmech05k|Installing "​Slobber Stoppers"​ (1991-1993 Models)]] 
 +  * **Related articles in the Sportsterpedia**.
     * [[techtalk:​ref:​engmech04k|Breather Valves (1957-Up)]] (list of breather valve changes)     * [[techtalk:​ref:​engmech04k|Breather Valves (1957-Up)]] (list of breather valve changes)
     * [[techtalk:​ref:​engmech05|Breather Venting / Relocation]] (list of breathing mods and aftermarket breathers)     * [[techtalk:​ref:​engmech05|Breather Venting / Relocation]] (list of breathing mods and aftermarket breathers)
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 **Maintaining your OEM breather umbrella valve(s) is not something you do every five years or so**. \\ **Maintaining your OEM breather umbrella valve(s) is not something you do every five years or so**. \\
-Harley considers them a normal replacement item. ((XLXR of the XLFORUM ​http://​xlforum.net/​forums/showthread.php?​t=1946516)) \\+Harley considers them a normal replacement item. ((XLXR of the XLFORUM ​https://www.xlforum.net/​forum/sportster-motorcycle-forum/​sportster-motorcycle-intake-and-exhaust/​sportster-motorcycle-air-intake-carburetor-efi-fuel-and-exhaust/​180842-crankcase-vent-question?​t=1946516)) \\
 The biggest problem occurs when the stock umbrella valves blow out or get hard and quit working as one way valves. \\ The biggest problem occurs when the stock umbrella valves blow out or get hard and quit working as one way valves. \\
 The purpose of one way valves is to allow the air in the crank case to be pushed out as the pistons go down. \\ The purpose of one way valves is to allow the air in the crank case to be pushed out as the pistons go down. \\
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 **General statements on modifications of OEM components**:​ \\ **General statements on modifications of OEM components**:​ \\
 If you're discussing engine breathing mods, you're also discussing changing crankcase pressure. \\ If you're discussing engine breathing mods, you're also discussing changing crankcase pressure. \\
-Revised crankcase breathing is an area where you have huge potential to create unintended consequences. ((maru of theXLFORUM ​http://​xlforum.net/​forums/showthread.php?​t=75740&​highlight=reed+valve&​page=6)) \\+Revised crankcase breathing is an area where you have huge potential to create unintended consequences. ((maru of theXLFORUM ​https://www.xlforum.net/​forum/sportster-motorcycle-forum/​sportster-motorcycle-motor-engine/​sportster-motorcycle-engine-conversions/​38153-xr750-883-series-race-engine-venting-etc/​page6?​t=75740&​highlight=reed+valve&​page=6)) \\
 Few really understand the ifs, ands and buts of all the factors the factory took into consideration when they designed the system. \\ Few really understand the ifs, ands and buts of all the factors the factory took into consideration when they designed the system. \\
 The MoCo somehow balanced the engine design factors to come up with a compromise that worked. \\ The MoCo somehow balanced the engine design factors to come up with a compromise that worked. \\
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     * 1990-prior breather valves (although obsoleted at the MoCo) are available online at times. \\ Sometimes you just have to wait and search to find them. \\ NOS valves can sometimes be found at dealerships but you'll have to contact them and ask. \\ (sometimes a phone call or in person will get better responses than emails).     * 1990-prior breather valves (although obsoleted at the MoCo) are available online at times. \\ Sometimes you just have to wait and search to find them. \\ NOS valves can sometimes be found at dealerships but you'll have to contact them and ask. \\ (sometimes a phone call or in person will get better responses than emails).
     * 1977-up engines all use one way breather valves although exact construction and venting changed over the years. \\ 1977-1990 engines all vented from the cam cover. \\ So an external motorcycle one way breather valve (that can be plumbed sufficiently) can be installed externally in the same place. \\ 1977-up engines also all begin making full vacuum starting from when the second piston begins it's upstroke motion. \\ So any external motorcycle one way breather valve (that can be plumbed sufficiently) will work on 1977-up Sportsters. \\ It is important to note that while using an external breather valve, the internal valve should be removed. \\ Leaving the old valve inside will only create more restriction to the air moving out of the engine.     * 1977-up engines all use one way breather valves although exact construction and venting changed over the years. \\ 1977-1990 engines all vented from the cam cover. \\ So an external motorcycle one way breather valve (that can be plumbed sufficiently) can be installed externally in the same place. \\ 1977-up engines also all begin making full vacuum starting from when the second piston begins it's upstroke motion. \\ So any external motorcycle one way breather valve (that can be plumbed sufficiently) will work on 1977-up Sportsters. \\ It is important to note that while using an external breather valve, the internal valve should be removed. \\ Leaving the old valve inside will only create more restriction to the air moving out of the engine.
 +  - **There is no sensible reason to change air cleaners or engine breathing just because that's someone else did**.
 +    * If your goal is simply to change the overall appearance, by all means, make it your own. \\ But understand that sometimes you can help or hurt the breathing system by what changes you make and all engines are different. \\ You can test the crankcase pressure to find out what your engine is doing or needs so you'll know where to go from there. ​
   - **One advantage of venting to atmosphere is cleaner combustion (and cleaner pistons)**.   - **One advantage of venting to atmosphere is cleaner combustion (and cleaner pistons)**.
     * There is also a case against improper installation of external vent(s). \\ There are many aftermarket and homemade breather vent relocation mods available to move the vents out of the air cleaner. \\ However, depending on how you route the vent lines, you can cause emulsified oil accumulation in them. \\ Emulsified oil will just build up in the tubes until it all comes out. And it could also alter engine breathing if it doesn'​t come out.     * There is also a case against improper installation of external vent(s). \\ There are many aftermarket and homemade breather vent relocation mods available to move the vents out of the air cleaner. \\ However, depending on how you route the vent lines, you can cause emulsified oil accumulation in them. \\ Emulsified oil will just build up in the tubes until it all comes out. And it could also alter engine breathing if it doesn'​t come out.
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     * OUR breather valve ads X amount of horsepower to your engine. \\ The reality is there is no data from aftermarket breathers manufacturers showing any horsepower gains from testing done on their breather valves.     * OUR breather valve ads X amount of horsepower to your engine. \\ The reality is there is no data from aftermarket breathers manufacturers showing any horsepower gains from testing done on their breather valves.
     * Hayden makes that claim, maybe others also, but they offer no evidence as to how their valve adds horsepower.     * Hayden makes that claim, maybe others also, but they offer no evidence as to how their valve adds horsepower.
-    * Testing was done however to prove whether any breather vent in particular could make extra horsepower. \\ See comments by aswracing below on venting mods to obtain more horsepower: ((aswracing of the XLFORUM ​http://​xlforum.net/​forums/showthread.php?​t=75740&​highlight=reed+valve&​page=6)) +    * Testing was done however to prove whether any breather vent in particular could make extra horsepower. \\ See comments by aswracing below on venting mods to obtain more horsepower: ((aswracing of the XLFORUM ​https://www.xlforum.net/​forum/sportster-motorcycle-forum/​sportster-motorcycle-motor-engine/​sportster-motorcycle-engine-conversions/​38153-xr750-883-series-race-engine-venting-etc/​page6?​t=75740&​highlight=reed+valve&​page=6)) 
-      * I've induced scavenging issues mostly from using gapless rings. But not from venting mods. \\ However, I've dyno tested venting mods until I'm blue in the face and never found a single horsepower there. \\ (except for pulling the blow by out of the intake tract, which is good for a small across the board improvement) \\ S&S cases have no scavenging issues due to the strategic placement of the reed valve (in the sump). \\ The scavenge inlet sees pressure but is isolated from the vacuum when the pistons go back up. \\ In addition to the above, I also did a bunch of testing of the aftermarket breather check valves from Spyke and Hayden. ((aswracing of the XLFORUM ​http://​xlforum.net/​forums/showthread.php?​t=1946516&​page=4)) ​ \\ (and even did some experiments with vacuum pumps and the like) Did some magazine articles here and there at the time. \\ The motor was remarkably insensitive to anything I did with the breathers. \\ Like I said, the only thing I could get to show up on the Dyno sheet at all was the removing of the blow-by from the intake tract. +      * I've induced scavenging issues mostly from using gapless rings. But not from venting mods. \\ However, I've dyno tested venting mods until I'm blue in the face and never found a single horsepower there. \\ (except for pulling the blow by out of the intake tract, which is good for a small across the board improvement) \\ S&S cases have no scavenging issues due to the strategic placement of the reed valve (in the sump). \\ The scavenge inlet sees pressure but is isolated from the vacuum when the pistons go back up. \\ In addition to the above, I also did a bunch of testing of the aftermarket breather check valves from Spyke and Hayden. ((aswracing of the XLFORUM ​https://www.xlforum.net/​forum/sportster-motorcycle-forum/​sportster-motorcycle-intake-and-exhaust/​sportster-motorcycle-air-intake-carburetor-efi-fuel-and-exhaust/​180842-crankcase-vent-question/​page4?​t=1946516&​page=4)) ​ \\ (and even did some experiments with vacuum pumps and the like) Did some magazine articles here and there at the time. \\ The motor was remarkably insensitive to anything I did with the breathers. \\ Like I said, the only thing I could get to show up on the Dyno sheet at all was the removing of the blow-by from the intake tract. 
- +  - **Stage 1 or higher air cleaner changes makes OEM breather venting impossible**. 
- +      * It is still possible to keep the venting into the air cleaner when upgrading OEM air cleaners. \\ You may have to get creative with plumbing or fabrication in some instances however. 
 +      * You may also want to take advantage of some of the mods listed in the sub documents at the top of this page. \\ Again changing the breathing system can have it's downfalls and should only be done to improve the breathing system. \\ Testing the internal air pressure after performing breather mods will tell you if the mods helped or hurt the system.  ​
  
 ====== Vent Outlet Above vs Below the Head Vents ====== ====== Vent Outlet Above vs Below the Head Vents ======
- 
 There has been debatable ways to route the vent lines off the heads when doing air cleaner mods. \\ There has been debatable ways to route the vent lines off the heads when doing air cleaner mods. \\
 However, exact line routing comes down to function over fashion. \\ However, exact line routing comes down to function over fashion. \\
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 Vent lines mounted high tend to promote a mixture of oil and condensation settling near the head connection of the hose. \\ Vent lines mounted high tend to promote a mixture of oil and condensation settling near the head connection of the hose. \\
-{{techtalk:​ref:​engmech:​kuryakyn_breather_bolts_1_by_scar55.jpg?​direct&​300|}} ((photo by Scar55 of the XLFORUM ​http://​xlforum.net/​forums/showthread.php?​t=1690623)) {{techtalk:​ref:​engmech:​kuryakyn_breather_bolts_2_by_scar55.jpg?​direct&​300|}} ((photo by Scar55 of the XLFORUM ​http://​xlforum.net/​forums/showthread.php?​t=1690623)) ​+{{techtalk:​ref:​engmech:​kuryakyn_breather_bolts_1_by_scar55.jpg?​direct&​300|}} ((photo by Scar55 of the XLFORUM ​https://www.xlforum.net/​forum/sportster-motorcycle-forum/​sportster-motorcycle-intake-and-exhaust/​sportster-motorcycle-air-intake-carburetor-efi-fuel-and-exhaust/​157991-ooozzz-running-out-of-my-crank-case-breather-hose?​t=1690623)) {{techtalk:​ref:​engmech:​kuryakyn_breather_bolts_2_by_scar55.jpg?​direct&​300|}} ((photo by Scar55 of the XLFORUM ​https://www.xlforum.net/​forum/sportster-motorcycle-forum/​sportster-motorcycle-intake-and-exhaust/​sportster-motorcycle-air-intake-carburetor-efi-fuel-and-exhaust/​157991-ooozzz-running-out-of-my-crank-case-breather-hose?​t=1690623)) ​
  
 **Horseshoe Tube**: \\ **Horseshoe Tube**: \\
-The horseshoe breathers that take the outlet from the breather bolts upwards tend to clog with foamy oily gunk. ((FoxsterUK of the XLFORUM ​http://​xlforum.net/​forums/showthread.php?​threadid=544771)) \\+The horseshoe breathers that take the outlet from the breather bolts upwards tend to clog with foamy oily gunk. ((FoxsterUK of the XLFORUM ​https://www.xlforum.net/​forum/sportster-motorcycle-forum/​sportster-motorcycle-intake-and-exhaust/​sportster-motorcycle-air-intake-carburetor-efi-fuel-and-exhaust/​76554-crankcase-breather-horseshoe-leak?​threadid=544771)) \\
 It's a low pressure output with not enough to push the sludge upwards and around the bend. \\  It's a low pressure output with not enough to push the sludge upwards and around the bend. \\ 
 This means the breather bolts are swimming in this gunk and if there is a small leak there is plenty to leak. \\ This means the breather bolts are swimming in this gunk and if there is a small leak there is plenty to leak. \\
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 {{:​techtalk:​ref:​engmech:​horseshoe_breather_tube_mounted_high_1_by_hippysmack.jpg?​direct&​400|}} ((drawing by Hippysmack)) {{:​techtalk:​ref:​engmech:​horseshoe_breather_tube_mounted_high_2_by_hippysmack.jpg?​direct&​400|}} ((drawing by Hippysmack)) \\ {{:​techtalk:​ref:​engmech:​horseshoe_breather_tube_mounted_high_1_by_hippysmack.jpg?​direct&​400|}} ((drawing by Hippysmack)) {{:​techtalk:​ref:​engmech:​horseshoe_breather_tube_mounted_high_2_by_hippysmack.jpg?​direct&​400|}} ((drawing by Hippysmack)) \\
  
-|Horseshoe tube, high mount / vent line in front. ((photo by OakBehringer of the XLFORUM ​http://​xlforum.net/​forums/showthread.php?​t=2004878))|Rear bolt covered in sludge. ((photo by OakBehringer of the XLFORUM ​http://​xlforum.net/​forums/showthread.php?​t=2004878))|Filter mounted high will receive built up sludge. ((photo by AustinXL of the XLFORUM ​http://​xlforum.net/​forums/showthread.php?​t=1507294))|+|Horseshoe tube, high mount / vent line in front. ((photo by OakBehringer of the XLFORUM ​https://www.xlforum.net/​forum/sportster-motorcycle-forum/​sportster-motorcycle-general-discussion-and-problems/​187981-horseshoe-breathers-do-they-suck-a-cautionary-post?​t=2004878))|Rear bolt covered in sludge. ((photo by OakBehringer of the XLFORUM ​https://www.xlforum.net/​forum/sportster-motorcycle-forum/​sportster-motorcycle-general-discussion-and-problems/​187981-horseshoe-breathers-do-they-suck-a-cautionary-post?​t=2004878))|Filter mounted high will receive built up sludge. ((photo by AustinXL of the XLFORUM ​https://www.xlforum.net/​forum/sportster-motorcycle-buell-motorcycle-forum-general-discussion/​dealers-stealers-indys-and-parts-dealers/​138877-dk-customs?​t=1507294))|
 |{{:​techtalk:​ref:​engmech:​horseshoe_tube_mounted_high_2_by_oakbehringer.jpg?​direct&​300|}}|{{:​techtalk:​ref:​engmech:​horseshoe_tube_mounted_high_1_by_oakbehringer.jpg?​direct&​300|}}|{{:​techtalk:​ref:​engmech:​horseshoe_breather_mod_up_high_by_austinxl.jpg?​direct&​300|}}| |{{:​techtalk:​ref:​engmech:​horseshoe_tube_mounted_high_2_by_oakbehringer.jpg?​direct&​300|}}|{{:​techtalk:​ref:​engmech:​horseshoe_tube_mounted_high_1_by_oakbehringer.jpg?​direct&​300|}}|{{:​techtalk:​ref:​engmech:​horseshoe_breather_mod_up_high_by_austinxl.jpg?​direct&​300|}}|
  
 Vent lines mounted lower than the head vents allow oil / condensation to leave the heads. \\ Vent lines mounted lower than the head vents allow oil / condensation to leave the heads. \\
  
-|This way, sludge can form on each side of filter. ((photo by beuz of the XLFORUM ​http://​xlforum.net/​forums/showthread.php?​t=11697&​page=582))|This way promotes less sludge buildup. ((photo by IXL2Relax of the XLFORUM ​http://​xlforum.net/​forums/showthread.php?​t=1051311&​page=46)) |+|This way, sludge can form on each side of filter. ((photo by beuz of the XLFORUM ​https://www.xlforum.net/​forum/sportster-motorcycle-forum/​sportster-motorcycle-styles/​chopper-bobber-talk/​7694-sporty-bobber-pictures/​page582?​t=11697&​page=582))|This way promotes less sludge buildup. ((photo by IXL2Relax of the XLFORUM ​https://www.xlforum.net/​forum/sportster-motorcycle-forum/​sportster-motorcycle-intake-and-exhaust/​sportster-motorcycle-air-intake-carburetor-efi-fuel-and-exhaust/​111555-air-cleaner-porn/​page31?​t=1051311&​page=46)) |
 |{{:​techtalk:​ref:​carb:​breather_lines_mounted_low_by_beuz.jpg?​direct&​300|}}|{{:​techtalk:​ref:​carb:​breather_lines_mounted_low_by_ixl2relax.jpg?​direct&​300|}}| |{{:​techtalk:​ref:​carb:​breather_lines_mounted_low_by_beuz.jpg?​direct&​300|}}|{{:​techtalk:​ref:​carb:​breather_lines_mounted_low_by_ixl2relax.jpg?​direct&​300|}}|
  
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 ====== Breather Bolts ====== ====== Breather Bolts ======
 ===== OEM Breathe Bolts ===== ===== OEM Breathe Bolts =====
- 
 Crankcase pressure was increased in 2004 by several means. \\ Crankcase pressure was increased in 2004 by several means. \\
 One of which was the reduction of the hole size in the breather bolts on the engine side (more restriction). \\ One of which was the reduction of the hole size in the breather bolts on the engine side (more restriction). \\
-The smaller hole creates higher pressure in the crankcase on piston downstroke which aides in oil scavenging. \\ +The smaller hole creates higher ​(positive) ​pressure in the crankcase on piston downstroke which aides in oil scavenging. \\ 
-They also allow the air to leave the vents at a faster rate. \\ +They also allow the air to leave the vents at a faster ​(pressure) ​rate. \\ 
 The threads in these bolts are cut wider for a tighter fit into the heads. \\ The threads in these bolts are cut wider for a tighter fit into the heads. \\
  
-{{:​techtalk:​evo:​carb:​91-03_breather_bolts_1_by_hippysmack.jpg?​direct&​300|}} ((photo by Hippysmack)) {{:​techtalk:​evo:​engmech:​04_up_breather_bolt_2_by_folkie.jpg?​direct&​300|}} ((photo by Folkie of the XLFORUM ​http://​xlforum.net/​forums/showthread.php?​p=5756327#post5756327))  {{:​techtalk:​evo:​engmech:​04_up_breather_bolt_1_by_folkie.jpg?​direct&​300|}} ((photo by Folkie of the XLFORUM ​http://​xlforum.net/​forums/showthread.php?​p=5756327#post5756327)) +{{:​techtalk:​evo:​carb:​91-03_breather_bolts_1_by_hippysmack.jpg?​direct&​300|}} ((photo by Hippysmack)) {{:​techtalk:​evo:​engmech:​04_up_breather_bolt_2_by_folkie.jpg?​direct&​300|}} ((photo by Folkie of the XLFORUM ​https://www.xlforum.net/​forum/sportster-motorcycle-forum/​sportster-motorcycle-intake-and-exhaust/​sportster-motorcycle-air-intake-carburetor-efi-fuel-and-exhaust/​28874-stock-air-cleaner-box-modifications/​page20#post4310316))  {{:​techtalk:​evo:​engmech:​04_up_breather_bolt_1_by_folkie.jpg?​direct&​300|}} ((photo by Folkie of the XLFORUM ​https://www.xlforum.net/​forum/sportster-motorcycle-forum/​sportster-motorcycle-intake-and-exhaust/​sportster-motorcycle-air-intake-carburetor-efi-fuel-and-exhaust/​28874-stock-air-cleaner-box-modifications/​page20#post4310316)) 
  
 ===== Aftermarket Banjo Bolts ===== ===== Aftermarket Banjo Bolts =====
- 
 Aftermarket breather bolts have a larger hole in the bolts than the 04+ bolts. \\ Aftermarket breather bolts have a larger hole in the bolts than the 04+ bolts. \\
-The banjo bolt must be indexed to have the small side hole on top. ((rejeanprimeau of the XLFORUM ​http://​xlforum.net/​forums/showthread.php?​t=2004878&​page=2)) \\+The banjo bolt must be indexed to have the small side hole on top. ((rejeanprimeau of the XLFORUM ​https://www.xlforum.net/​forum/sportster-motorcycle-forum/​sportster-motorcycle-general-discussion-and-problems/​187981-horseshoe-breathers-do-they-suck-a-cautionary-post/​page2?​t=2004878&​page=2)) \\
 If not, they will drip more. You can adjust them with copper washers. \\ If not, they will drip more. You can adjust them with copper washers. \\
  
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 On 04-up heads, changing to aftermarket breather bolts means using bolts with the bigger I.D. (91-03) style bolts. \\ On 04-up heads, changing to aftermarket breather bolts means using bolts with the bigger I.D. (91-03) style bolts. \\
-The results of using the bigger holed bolt would be a slower rate of outflow and less positive crankcase pressure on a stock motor. ((Hippysmack of the XLFORUM ​http://​xlforum.net/​forums/showthread.php?​t=2073932&​page=4)) \\+The results of using the bigger holed bolt would be a slower rate of outflow and less positive crankcase pressure on a stock motor. ((Hippysmack of the XLFORUM ​https://www.xlforum.net/​forum/sportster-motorcycle-forum/​sportster-motorcycle-motor-engine/​sportster-motorcycle-bottom-end/​197307-sportster-crankcase-pressure-engine-breathing-wetsumping-and-mods/​page4?​t=2073932&​page=4)) \\
 But the timing of the upstroke is the same which then pulls a vacuum. \\ But the timing of the upstroke is the same which then pulls a vacuum. \\
 The umbrella valve will close down only when inside air pressure is lower than outside air pressure. \\ The umbrella valve will close down only when inside air pressure is lower than outside air pressure. \\
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 This may be something you'd want to watch since there isn't sufficient data to prove one way or the other. \\ This may be something you'd want to watch since there isn't sufficient data to prove one way or the other. \\
  
-{{:​techtalk:​ref:​engmech:​breather_mod_2_by_hagen.jpg?​direct&​300|}} ((photo by Hagen of the XLFORUM ​http://​xlforum.net/​forums/showthread.php?​t=146084&​page=11)) {{:​techtalk:​ref:​engmech:​ds_breather_bolt_by_hagen.png?​direct&​300|}} ((photo by Hagen of theXLFORIM ​http://​xlforum.net/​forums/showthread.php?t=692845)) {{:​techtalk:​ref:​engmech:​broken_banjo_bolt_by_scout99.jpg?​direct&​200|}} ((photo by Scout99 of the XLFORUM ​http://​xlforum.net/​forums/showthread.php?t=28299))+{{:​techtalk:​ref:​engmech:​breather_mod_2_by_hagen.jpg?​direct&​300|}} ((photo by Hagen of the XLFORUM ​https://www.xlforum.net/​forum/sportster-motorcycle-forum/​sportster-motorcycle-intake-and-exhaust/​sportster-motorcycle-air-intake-carburetor-efi-fuel-and-exhaust/​44522-show-me-your-non-stock-breather-systems/​page11?​t=146084&​page=11)) {{:​techtalk:​ref:​engmech:​ds_breather_bolt_by_hagen.png?​direct&​300|}} ((photo by Hagen of theXLFORIM ​https://www.xlforum.net/​forum/sportster-motorcycle-forum/​sportster-motorcycle-intake-and-exhaust/​sportster-motorcycle-air-intake-carburetor-efi-fuel-and-exhaust/​87720-need-some-help-installing-my-breather-bolts?t=692845)) {{:​techtalk:​ref:​engmech:​broken_banjo_bolt_by_scout99.jpg?​direct&​200|}} ((photo by Scout99 of the XLFORUM ​https://www.xlforum.net/​forum/sportster-motorcycle-forum/​sportster-motorcycle-intake-and-exhaust/​sportster-motorcycle-air-intake-carburetor-efi-fuel-and-exhaust/​16986-broken-carb-mounting-bracket?t=28299))
  
 ====== Filter on End of the Vent Line ====== ====== Filter on End of the Vent Line ======
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 A stopped up filter can also increase the vacuum inside the engine, which on a street bike, translates to weeping gaskets. \\ A stopped up filter can also increase the vacuum inside the engine, which on a street bike, translates to weeping gaskets. \\
  
-The filter does not keep debris from coming back into the engine. ((Folkie of the XLFORUM ​http://​xlforum.net/​forums/showthread.php?​p=2087347)) That's the job of the breather valves inside the engine. \\+The filter does not keep debris from coming back into the engine. ((Folkie of the XLFORUM ​https://www.xlforum.net/​forum/sportster-motorcycle-forum/​sportster-motorcycle-motor-engine/​sportster-motorcycle-motor-top-end/​78453-crankcase-breather-aka-stupid/​page2#​post1632160)) That's the job of the breather valves inside the engine. \\
 If anything can get back in, it means your umbrella valves are shot. \\ If anything can get back in, it means your umbrella valves are shot. \\
 There will be quite a bit of oil coming out the breathers, and all sorts of stuff going back in. \\ There will be quite a bit of oil coming out the breathers, and all sorts of stuff going back in. \\
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 ===== Filter Placement / Maintenance ===== ===== Filter Placement / Maintenance =====
- 
 Adding a filter on the end of the line and hanging the filter lower than the vent can cause filter blockage. \\ Adding a filter on the end of the line and hanging the filter lower than the vent can cause filter blockage. \\
 No matter what breathing system you are using, a certain amount of oil / air mist still makes it past the breather. \\ No matter what breathing system you are using, a certain amount of oil / air mist still makes it past the breather. \\
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 The filter in the first pic below was full of junk contributing to weeping rocker box gaskets. \\ The filter in the first pic below was full of junk contributing to weeping rocker box gaskets. \\
  
-{{:​techtalk:​ref:​engmech:​clogged_breather_filter_by_60gunner.jpg?​direct&​300|}} ((photo by 60Gunner of the XLFORUM ​http://xlforum.net/​forums/​showthread.php?​t=2074059&​page=5)) {{:​techtalk:​ref:​engmech:​05_breather_mod_2_by_socal1200R_annotated_by_hippysmack.jpg?​direct&​300|}} ((photo by socal1200r of the XLFORUM, annotated by Hippysmack http://xlforum.net/​forums/showthread.php?​t=30844)) +{{:​techtalk:​ref:​engmech:​clogged_breather_filter_by_60gunner.jpg?​direct&​300|}} ((photo by 60Gunner of the XLFORUM ​https://www.xlforum.net/​forum/sportster-motorcycle-forum/sportster-motorcycle-motor-engine/sportster-motorcycle-motor-top-end/197429-wtf-is-it-with-these-f-n-rocker-cover-leaks/page5?t=2074059&page=5)) {{:​techtalk:​ref:​engmech:​05_breather_mod_2_by_socal1200R_annotated_by_hippysmack.jpg?​direct&​300|}} ((photo by socal1200r ​of the XLFORUM, annotated by Hippysmack https://www.xlforum.net/​forum/sportster-motorcycle-forum/sportster-motorcycle-intake-and-exhaust/sportster-motorcycle-air-intake-carburetor-efi-fuel-and-exhaust/18515-ram-flo-horseshoe-breather-option?t=30844))
- +
-====== Aftermarket Breather Valves ====== +
- +
-==== Sub Documents ==== +
-  * [[techtalk:​ref:​engmech04a|Dissecting the Hayden KVP38 Crankcase Breather Valve]] +
-  * [[techtalk:​ref:​engmech04b|Frequently Asked Questions About the Hayden Krankvent]] ​  +
- +
-There is a product called a Krankvent that can be plumbed into the lower, 6 o’clock position as an alternative to a stock foo-foo valve. ((Hopper of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=518948&​highlight=cam+chest+breather)) \\ +
-But they are not cheap. Automotive PCV valves are not really made to handle the revs or air volumes of a Harley. \\ +
-While a car engine is bigger, it has one piston coming down while one goes up. \\ +
-So there'​s not much change in internal crankcase volume, so not as much breathing to be done. \\ +
-A Harley has two pistons and rods on one crankpin, so is one giant air compressor. \\ +
- +
-**Finding a better breather valve**: ((bunny32 of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=15705&​page=2)) \\ +
-The breather valves that work best on crankcase breathers have several features: \\ +
-  * Low-inertia, i.e. they don't take more than a breath to open and close. +
-  * They operate at low pressures ~1-30psi. +
-  * They preferably have a floating type seal. +
-  * They should be transparent,​ so you can see if they block up with blowby, solids, bugs etc. +
-  * They should be easy to open and clean occasionally. +
-  * They should push-fit into your breather line. +
- +
-Metal diaphragm valves with e.g. springs are hopeless. \\ +
-Also avoid other types of valves designed to work at high pressures e.g. plumbing valves. \\ +
-Avoid car PCV valves as they are metering as well as non-return valves and are unsuitable. \\ +
-Automotive PCV valves are designed to let some air back in. \\ +
-The ball and spring valves will not be able to work fast enough to keep all the air out. \\ +
-When air is allowed to be drawn back into the engine, it creates a mass that must be compressed by the pistons on downstroke as it is being vented out. \\ +
-This robs some power and will cause the engine to work harder (creating more internal heat at higher RPM). ((Deimus of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=67658&​page=18)) \\ +
- +
-Aftermarket Breather Valves for Harley'​s:​ \\ +
-  * Sifton Crankcase Breather ((https://​www.ebay.com/​itm/SIFTON-CASE-BREATHER-VENT-PCV-VALVE-HARLEY-EVO-SHOVELHEAD-PANHEAD-TWINCAM-KRANK/​253213372444?​epid=1665559744&​hash=item3af4b1701c:​g:​F4cAAOSwzrxUuDhJ)) \\ This appears to be a cheaper version of the Hayden Crankvent also with an umbrella valve installed inside. \\ It is, however, a one time use part as it cannot be taken apart to replace the umbrella valve.  +
- +
-Aftermarket PCV's: ((electronbee of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=72099&​highlight=reed+valve&​page=10)) \\ +
-  * Mercedes Benz P/N# 271-018-00-29 ~$13. +
-    * Reed type PCV valve. Fast acting. Used for their C 230 Kompressor engine. +
-    * Dims: 2-1/2" long by 1-1/8" with an I.D of 1/4".  +
-  * McCaster Carr P/N# 4610K17 ~$6. +
-    * Umbrella valve. Vacuum check valve. +
-  * Autozone P/N# PCV1174 (PV272) ~$5. +
-  * Ball/spring based PCV valve. +
-    * Makes a clicking noise during operation. +
- +
- +
-|Hayden KVP38 breather valve, used with the \\ [[techtalk:​ref:​engmech05d|Deimus Mod]] (cam chest breather conversion). ((photo by 60Gunner of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​p=5763918#​post5763918))| ​ Hayden breather opened up. ((photos by leucadiaGuit of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=2004869 cropped by Hippysmack)) ​ || +
-|{{:​techtalk:​ref:​engmech:​deimus_mod_8_by_60gunner.jpg?​direct&​300|}}|{{:​techtalk:​ref:​engmech:​hayden_krankvent_3_by_leucadiaguit_-_cropped.jpg?​direct&​300|}}|{{:​techtalk:​ref:​engmech:​hayden_krankvent_2_by_leucadiaguit_-_cropped.jpg?​direct&​300|}}| +
- +
-|Doherty Power Vents with the line routed up then \\ down and attached to the bottom of the frame. ((photo by RIORoosen of the XLFORUM http://​xlforum.net/​forums/​showthread.php?t=146084&page=18))|  Doherty Power Vent ((Photo by goblin_dust of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=72099&​highlight=wet+sumping&​page=23)) ​ | +
-|{{:​techtalk:​ref:​engmech:​breather_mod_by_rioroosen.jpg?​direct&​300|}}|{{:​techtalk:​ref:​engmech:​deimus_mod_2_by_goblin_dust.jpg?​direct&​300|}}| +
- +
- +
-|  Here is a 2-stroke reed valve. ​((photo by norseXL ​of the XLFORUM ​http://xlforum.net/​forums/​showthread.php?​t=1386341&​highlight=reed)) ​ |  Reed Valve ((photo by Bluto of the XLFORUM http://xlforum.net/​forums/showthread.php?​p=5761290#​post5761290)) ​ | +
-|{{:​techtalk:​ref:​engmech:​reed_valve_by_norsexl.jpg?​direct&​300|}}|{{:​techtalk:​ref:​engmech:​reed_valve_by_bluto.jpg?​direct&​300|}}| +
- +
-|  Mercedes Benz P/N# 271-018-00-29 ((photo by electronbee of the XLFORUM http://xlforum.net/​forums/​showthread.php?t=72099&​highlight=reed+valve&​page=10))  | +
-|{{:​techtalk:​ref:​engmech:​mercedes_benz_pcv_valve_by_electronbee.jpg?​direct&​300|}}|+
  
 ====== Homemade Breather Valves ====== ====== Homemade Breather Valves ======
-This was made by norseXL of the XLFORUM and is a direct derivative of the 86-90 breather valve setup.((http://​xlforum.net/​forums/showthread.php?​p=5809352#post5809352)) \\+This was made by norseXL of the XLFORUM and is a direct derivative of the 86-90 breather valve setup.((https://www.xlforum.net/​forum/sportster-motorcycle-forum/​sportster-motorcycle-motor-engine/​sportster-motorcycle-bottom-end/​36799-installing-the-ultimate-crankcase-vent-%C2%93how-to%C2%94/​page23#post4383140)) \\
  
 A male threaded cap was made to screw into the female threaded body of the breather valve container as shown below. \\ A male threaded cap was made to screw into the female threaded body of the breather valve container as shown below. \\
Line 301: Line 244:
 The umbrella inside the body is the stock 91-03 umbrella. \\ The umbrella inside the body is the stock 91-03 umbrella. \\
 A 1.5mm hole was drilled into the bottom side of the body to drain any oil that makes it past the umbrella. \\ A 1.5mm hole was drilled into the bottom side of the body to drain any oil that makes it past the umbrella. \\
- 
  
 {{:​techtalk:​ref:​engmech:​homemade_breather_vavle_1_by_norsexl.jpg?​direct&​300|}} {{:​techtalk:​ref:​engmech:​homemade_breather_vavle_3_by_norsexl.jpg?​direct&​300|}} \\ {{:​techtalk:​ref:​engmech:​homemade_breather_vavle_1_by_norsexl.jpg?​direct&​300|}} {{:​techtalk:​ref:​engmech:​homemade_breather_vavle_3_by_norsexl.jpg?​direct&​300|}} \\