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--- techtalk:ref:engmech04 [2019/08/18 04:41]
hippysmack [Why Oil Pukes Out the Air Cleaner]
+++ techtalk:ref:engmech04 [2019/10/12 01:15]
hippysmack [Breather Valves]
@@ Line 166: / Line 166: @@
 {{:techtalk:ref:engmech:86-90_sportster_positive_crankcase_pressure_by_hippysmack.jpg?direct&300|}} ((drawing by Hippysmack)) {{:techtalk:ref:engmech:86-90_sportster_negative_crankcase_pressure_by_hippysmack.jpg?direct&300|}} ((drawing by Hippysmack))
--03 models with head breather vents: \\
+-97 models with head breather vents: \\
-{{:techtalk:ref:engmech:91-03_sportster_positive_crankcase_pressure_by_hippysmack.jpg?direct&300|}} ((drawing by Hippysmack)) {{:techtalk:ref:engmech:91-03_sportster_negative_crankcase_pressure_by_hippysmack.jpg?direct&300|}} ((drawing by Hippysmack))
+{{:techtalk:ref:engmech:91-97_sportster_positive_crankcase_pressure_by_hippysmack.jpg?direct&300|}} {{:techtalk:ref:engmech:91-97_sportster_negative_crankcase_pressure_by_hippysmack.jpg?direct&300|}} \\
+-03 models with head breather vents: \\
+{{:techtalk:ref:engmech:98-03_sportster_positive_crankcase_pressure_by_hippysmack.jpg?direct&300|}} {{:techtalk:ref:engmech:98-03_sportster_negative_crankcase_pressure_by_hippysmack.jpg?direct&300|}} \\
 and Up models with head breather vents: \\
@@ Line 466: / Line 469: @@
 |{{:techtalk:ref:engmech:86-90_sportster_engine_breathing_by_hippysmack.jpg?direct&300|}}|{{:techtalk:ref:engmech:91_sportster_engine_breathing_by_hippysmack.jpg?direct&300|}}|
-|  92-03 engine breathing paths. ((drawing by Hippysmack))  |  04 and Up engine breathing paths. ((drawing by Hippysmack))  |
+|  92-97 engine breathing paths. ((drawing by Hippysmack))  |  98-03 engine breathing paths. ((drawing by Hippysmack))  |  04 and up engine breathing paths. ((drawing by Hippysmack))  |
-|{{:techtalk:ref:engmech:92-03_sportster_engine_breathing_by_hippysmack.jpg?direct&300|}}|{{:techtalk:ref:engmech:04_and_up_sportster_engine_breathing_by_hippysmack.jpg?direct&300|}}|
+|{{techtalk:ref:engmech:92-97_sportster_engine_breathing_by_hippysmack.jpg?direct&300|}}|{{techtalk:ref:engmech:98-03_sportster_engine_breathing_by_hippysmack.jpg?direct&300|}}|{{techtalk:ref:engmech:04_and_up_sportster_engine_breathing_by_hippysmack.jpg?direct&300|}}|
 |  Testing CC pressure on the dyno. ((photo by Jörgen http://xlforum.net/forums/showthread.php?t=75740&page=9))  |
@@ Line 542: / Line 544: @@
 ===== Breather Catch Can Test For Oil Leaks Out the Vent  =====
-A test was done by XLFORUM member cjburr. Test apparatus and results are below. \\
+A test was done by XLFORUM member cjburr. Test apparatus and results are below. ((cjburr of the XLFORUM http://xlforum.net/forums/showthread.php?t=53769&highlight=valve+guide&page=13)) \\
 This testing was done to help diagnose an oil leak that couldn't be seen or otherwise detected. \\
-However, this is a good exercise if you are concerned about how much oil you may be losing from the crankcase puking. \\
+However, this may be a good exercise if you are concerned about how much oil you may be losing from the crankcase puking. \\
+It should show what, how much and when oil accumulates in the hose / catch can. \\
+The length / size of tubing will change crankcase pressure to an extent so the results may not reflect exactly what's going on inside your engine. \\
 The vent to air cleaner was inspected and then removed for testing. The factory system routes the breathers to the front of the carb. \\
@@ Line 599: / Line 603: @@
 **Late 1982-Early 1984 models**: \\
- The internal crankcase breather valve was redesigned to incorporate a rubber umbrella valve attached to the base plate along with a larger diameter (1-3/4” O.D.) oil separator washer on the generator armature. ((HD Service Bulletin #M-848 dated April 9, 1982))
+The internal crankcase breather valve was redesigned to incorporate a rubber umbrella valve. \\
+This is attached to the base plate along with a larger diameter (1-3/4” O.D.) oil separator washer on the generator armature. ((HD Service Bulletin #M-848 dated April 9, 1982)) \\
 **Late 1984-1990 models**: \\
@@ Line 787: / Line 792: @@
 Oil was introduced into the head with a with a turkey baster. \\
 (which is probably a higher volume of oil than it normally sees from the splash oiling) \\
+However, if the drains were plugged, oil would overfill to the point of spewing oil at the seams and submerge the seals. ((cjburr of the XLFORUM http://xlforum.net/forums/showthread.php?t=53769&highlight=valve+guide&page=33)) \\
 |  Head ready for testing. ((photo by cjburr of the XLFORUM http://xlforum.net/forums/showthread.php?t=53769&highlight=valve+guide&page=31))  |  Oil poured in and draining. ((photo by cjburr of the XLFORUM http://xlforum.net/forums/showthread.php?t=53769&highlight=valve+guide&page=31))  |Oil level at the intake valve when it starts to drain to \\ the exhaust side. ((photo by cjburr of the XLFORUM http://xlforum.net/forums/showthread.php?t=53769&highlight=valve+guide&page=31))  |
@@ Line 1093: / Line 1099: @@
 ====== Vacuum Pump for Reducing Crankcase Pressure ======
+It's evident that many racers use vacuum pumps to increase vacuum pressure in the crankcase. ((Hippysmack of the XLFORUM http://xlforum.net/forums/showthread.php?t=2073932)) \\
+It's been said that positive crankcase pressure upon piston upstroke gets between the rings and basically causes bad sealing at the ringlands. \\
+This is also in the high RPM range when ring flutter is present. So there are several things happening then. \\
+But racers record higher power when using a vacuum pump. \\
+However, it has also been said that inducing higher vacuum in a street engine may do more harm than good. Lower RPM may suffer from the imbalance. \\
 A vacuum pump, in general, is an added benefit to any engine that is high performance enough to create a significant amount of blow-by. ((https://www.gzmotorsports.com/why-use-vacuum-pump.html)) \\
 (that's high performance enough.... not worn enough) \\

Trace:

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