Differences

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--- techtalk:evo:engmech07 [2019/11/14 04:01]
hippysmack [2004-Present Engine Breathing]
+++ techtalk:evo:engmech07 [2020/08/08 23:20]
hippysmack [1991-2003 Engine Breathing]
@@ Line 77: / Line 77: @@
 ====== 1991-2003 Engine Breathing ======
+**An important note**: \\
+Factory engine breather valves on all Evo Sportsters are inside the engine. \\
+The lines / hoses that leave the engine and any apparatus to route the air to different places are part of the venting system. \\
+Many aftermarket manufacturers advertise that they are selling "Engine Breathers when they are actually only selling the vent line / tube assemblies. \\
   * In 1991, along with the 5-speed transmission, the MoCo moved the crankcase breathing from the cam box cover outlet to breather bolts in the heads.  \\ Previously, these bolts were just used to mount the carb and air cleaner to the heads.
   * The new breather system uses one-way umbrella valves (AKA Foo Foo Valves) in the rocker boxes. \\ These exit crankcase vapors through vents in the top of the cylinder head into the carb mouth to be burnt. ((FoxsterUK of the XLFORUM  http://xlforum.net/forums/showthread.php?t=518948&highlight=wet+sumping))
@@ Line 88: / Line 93: @@
         * Air pressure escapes the head through the hollow bolts (one in each head) that hold the air cleaner mount.
-{{:techtalk:evo:engmech:a91-03_sportster_head_breathing_2_drawing_by_hippysmack.jpg?direct&300|}} ((drawing by Hippysmack)) {{:techtalk:evo:oil:crankcase_pressure_separation_chambe_by_hippysmack.jpg?direct&300|}} ((photo by Hippysmack))
+{{:techtalk:evo:engmech:91-03_sportster_head_breathing_2_drawing_by_hippysmack.jpg?direct&300|}} ((drawing by Hippysmack)) {{:techtalk:evo:oil:crankcase_pressure_separation_chambe_by_hippysmack.jpg?direct&300|}} ((photo by Hippysmack))
   * The Parts Catalog and FSM are a bit confusing regarding how many umbrellas are used and where. \\ The information is there but it's just not clear. \\ The parts catalog only shows an exploded diagram of one rocker box assembly on the Rocker Arms, Covers and Pushrods page. \\ Yet, the description shows that 2 umbrellas are required. \\ It's the same for all of the parts on that page as well as each newer parts catalog (1 pushrod, tube ,lifter and related parts). \\ This is the norm mostly throughout the subsequent catalogs with multiple (same) parts. \\ It's assumed this was done to save money on printing the catalogs (replicated information deleted). \\ The FSM displays the same exploded diagram as the parts catalog in the front of the Cylinder Head section. \\ It's only at the end of the Installation article does it say to install new gaskets on the middle rocker box (with the breather valve on the intake side). \\ There is no dedicated section on the rocker box or umbrella valves (which seem to be regarded as mere gaskets).
@@ Line 120: / Line 125: @@
         * Air pressure escapes the head through the hollow bolts (one in each head) that hold the air cleaner mount.
-{{:techtalk:evo:engmech:a04_up_head_breathing_drawing_2_by_hippysmack.jpg?direct&300|}} ((photo by Hippysmack))
+{{:techtalk:evo:engmech:04_up_head_breathing_drawing_2_by_hippysmack.jpg?direct&300|}} ((photo by Hippysmack))
 Just as with the 91-03 umbrella valves, only 1 breather valve per side is used. \\
@@ Line 180: / Line 185: @@
 == 91-03 ==
--03 breather bolts. \\
+-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))
@@ Line 190: / Line 195: @@
 They also allow the air to leave the vents at a faster rate. \\
-+ breather bolts (small hole is nominally 1/16" or 1.5875 mm). ((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)) \\
++ 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))
@@ Line 196: / Line 201: @@
 {{: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#engine_breathing|Engine Breathing System]] 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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