Differences

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--- techtalk:evo:engmech07 [2022/05/12 15:46]
hippysmack [Breather Valve Testing]
+++ techtalk:evo:engmech07 [2022/05/12 18:26]
hippysmack [Late 1984-1990 Sportster Breather Valve]
@@ Line 62: / Line 62: @@
 |{{:techtalk:evo:oil:89_cam_cover_1_by_bryan350.jpg?direct&250|}}|{{:techtalk:evo:oil:89_cam_cover_2_by_bryan350.jpg?direct&250|}}|{{:techtalk:evo:oil:89_cam_cover_3_by_bryan350.jpg?direct&250|}}|
 |  89 cam cover with breather baffle tube attached (it should be tight but still pull out) ((photos by Bryan350 of the XLFORUM http://xlforum.net/forums/showthread.php?t=1712011))  |||
-**Testing the L84-90 umbrella valve**: \\
-A working valve should help reduce oil mist. ((Four Speed of the XLFORUM http://xlforum.net/forums/showthread.php?p=5745528#post5745528)) \\
-Since it's a one-way valve, air goes out but doesn't come back in. \\
-To make sure the umbrella valve is still working; \\
-Before you position the hose, use a bit of clean pipe and blow gently through the breather. \\
-It should close the valve and stop air flow.
-You may have to find an aftermarket replacement if the valve is shot as OEM replacements are hard to come by now. \\
-The 5 speed ones do not fit.
 ====== 1991-2003 Sportster Breather Valve ======
@@ Line 202: / Line 192: @@
 {{:techtalk:evo:engmech:cometic_gasket_1_by_dieselvette.jpg?direct&300|}} ((photo by dieselvette of the XLFORUM http://xlforum.net/forums/showthread.php?p=5769573#post5769573)) {{:techtalk:evo:engmech:cometic_gasket_2_by_dieselvette.jpg?direct&300|}} ((photo by dieselvette of the XLFORUM http://xlforum.net/forums/showthread.php?p=5769573#post5769573))
+====== Head Breather Bolts ======
+===== Sub Documents =====
+  * [[techtalk:evo:engmech07a|Making 91-03 Breather Bolt Holes Smaller]]
+See also [[techtalk:ref:engmech04|Evo Crankcase Pressure and Engine Breathing]] in the REF section of the Sportsterpedia. \\
+Since 86-90 engines breath through the cam chest cover instead of the heads, the air cleaner bolts are solid (not hollowed). \\
+and up engines breath out the heads through hollowed out air cleaner mounting bolts (or breather bolts). \\
+Without the hole through the bolts, the engine can't breathe. \\
+The size of the orifice in the hollow head breather bolts makes the crankcase pressure rise higher (or lower) in the process of expelling the gas. ((aswracing of the XLFORUM http://xlforum.net/forums/showthread.php?p=4050323&highlight=breather+bolts#post4050323)) \\
+== 91-03 ==
+-03 breather bolts. \\ Outside threads are 1/2" x 13 (hole through the middle is 5/6" nominal). \\
+{{:techtalk:evo:carb:91-03_breather_bolts_1_by_hippysmack.jpg?direct&300|}} ((photo by Hippysmack)) {{:techtalk:evo:carb:91-03_breather_bolts_2_by_hippysmack.jpg?direct&300|}} ((photo by Hippysmack))
+== 04 and Up ==
+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). \\
+The smaller hole creates higher 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. \\
++ breather bolts. \\ Outside threads are 1/2" x 13 (2 different sizes thru the middle - nominally 1/16" (1.5875 mm) in the rear and 5/16" in the front). ((tomcat of the XLFORUM http://xlforum.net/forums/showthread.php?t=2073932&page=19)) ((Folkie of the XLFORUM http://xlforum.net/forums/showthread.php?t=2073932&page=22)) ((http://xlforum.net/forums/showthread.php?p=5756327#post5756327)) \\
+{{:techtalk:evo:engmech:04_up_breather_bolt_3_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_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))
+If you know someone with a lathe, you can have some stainless steel breather bolts made. ((photos by Folkie of the XLFORUM http://xlforum.net/forums/showthread.php?t=2073497&highlight=oil+level&page=7)) \\
+{{:techtalk:evo:engmech:stainless-steel-breather-bolts-1_by_folkie.jpg?direct&300|}} {{:techtalk:evo:engmech:stainless-steel-breather-bolts-2_by_folkie.jpg?direct&300|}}
+====== Symptoms of Breather problems ======
+Read more here on the [[techtalk:ref:engmech04|Evo Crankcase Pressure and Engine Breathing]] in the REF section of the Sportsterpedia. \\
+The most noticeable signs of breather valve problems are weeping gaskets or oil excessively leaking out the breather or puking oil out of it. \\
+When the umbrella(s) gets hard, it doesn't flex well to allow the engine to breath out on exhale. \\
+Then the trapped in air is compounded on the next stroke.  The excess air contributes to more vacuum created and implodes the gaskets. \\
+Or it contributes to too high of oil density and slings excess oil out. \\
+Other factors are involved so results will vary. \\
 ====== Breather Valve Testing ======
+[[techtalk:ref:engmech04#crankcase_pressure_testing|Click Here]] for information on testing crankcase pressure in the Sportsterpedia. \\
 There are no service intervals for the breather valve(s) in the FSMs. Also, there is no method of testing them in the FSMs. \\
 But when they harden over time, you might experience more oil vapor, oil droplets or oil puking out the breather vent(s). \\
@@ Line 240: / Line 271: @@
 Next, the rear piston rises creating a partial lowering of air pressure under the front piston. \\
 Full vacuum is not created until both pistons are on their up stroke. \\
-So there is a lull area in each cycle that can be perceived as both pressure and suction at the breather vent. \\
+So there is a lull area in each cycle that can be perceived as both pressure and suction at the breather vent even with good working umbrellas. \\
 {{:techtalk:evo:engmech:2004-up_breather_vent_-_how_air_vacuum_closes_it_by_hippysmack.png?direct&500|}} ((drawing by Hippysmack)) \\
-====== Head Breather Bolts ======
-===== Sub Documents =====
-  * [[techtalk:evo:engmech07a|Making 91-03 Breather Bolt Holes Smaller]]
-See also [[techtalk:ref:engmech04|Evo Crankcase Pressure and Engine Breathing]] in the REF section of the Sportsterpedia. \\
-Since 86-90 engines breath through the cam chest cover instead of the heads, the air cleaner bolts are solid (not hollowed). \\
-and up engines breath out the heads through hollowed out air cleaner mounting bolts (or breather bolts). \\
-Without the hole through the bolts, the engine can't breathe. \\
-The size of the orifice in the hollow head breather bolts makes the crankcase pressure rise higher (or lower) in the process of expelling the gas. ((aswracing of the XLFORUM http://xlforum.net/forums/showthread.php?p=4050323&highlight=breather+bolts#post4050323)) \\
-== 91-03 ==
--03 breather bolts. \\ Outside threads are 1/2" x 13 (hole through the middle is 5/6" nominal). \\
-{{:techtalk:evo:carb:91-03_breather_bolts_1_by_hippysmack.jpg?direct&300|}} ((photo by Hippysmack)) {{:techtalk:evo:carb:91-03_breather_bolts_2_by_hippysmack.jpg?direct&300|}} ((photo by Hippysmack))
-== 04 and Up ==
-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). \\
-The smaller hole creates higher 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. \\
-+ breather bolts. \\ Outside threads are 1/2" x 13 (2 different sizes thru the middle - nominally 1/16" (1.5875 mm) in the rear and 5/16" in the front). ((tomcat of the XLFORUM http://xlforum.net/forums/showthread.php?t=2073932&page=19)) ((Folkie of the XLFORUM http://xlforum.net/forums/showthread.php?t=2073932&page=22)) ((http://xlforum.net/forums/showthread.php?p=5756327#post5756327)) \\
-{{:techtalk:evo:engmech:04_up_breather_bolt_3_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_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))
-If you know someone with a lathe, you can have some stainless steel breather bolts made. ((photos by Folkie of the XLFORUM http://xlforum.net/forums/showthread.php?t=2073497&highlight=oil+level&page=7)) \\
-{{:techtalk:evo:engmech:stainless-steel-breather-bolts-1_by_folkie.jpg?direct&300|}} {{:techtalk:evo:engmech:stainless-steel-breather-bolts-2_by_folkie.jpg?direct&300|}}
-====== Symptoms of Breather problems ======
-Read more here on the [[techtalk:ref:engmech04|Evo Crankcase Pressure and Engine Breathing]] in the REF section of the Sportsterpedia. \\
-The most noticeable signs of breather valve problems are weeping gaskets or oil excessively leaking out the breather or puking oil out of it. \\
-When the umbrella(s) gets hard, it doesn't flex well to allow the engine to breath out on exhale. \\
-Then the trapped in air is compounded on the next stroke.  The excess air contributes to more vacuum created and implodes the gaskets. \\
-Or it contributes to too high of oil density and slings excess oil out. \\
-Other factors are involved so results will vary. \\
 \\

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