Differences

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--- techtalk:ih:oil01u [2020/08/08 00:19]
hippysmack created
+++ techtalk:ih:oil01u [2021/02/19 15:52]
hippysmack [Venting the Primary]
@@ Line 6: / Line 6: @@
 ====== Plug it or Not? ======
-There are many debates over the actual function of the transfer valve as well as plugging it. \\
+See [[techtalk:ih:oil01t|Further Study of the Transfer Valve Operation and Affects of Plugging the Valve]] in the Sportsterpedia. \\
-If you plug it, theoretically no more oil should enter the primary due to sit sumping. Read more on [[techtalk:ref:oil10#sit_sumpimg|Sit Sumping]] in the Sportsterpedia. \\
-Normally, if the bike does wet sump, excess oil will trickle into the primary case. ((Ferrous Head of the XLFORUM http://xlforum.net/forums/showthread.php?t=2077280&page=3)) \\
-When you start the engine, the return oil system will gradually empty the contents of the crank cases back to the tank. \\
-It will also shoot excess oil out through the gear case breather onto your clean floor. \\
-Once the excess oil is removed from the crank cases it will start drawing oil in through the transfer valve until the oil level is returned to it's correct level. \\
-At that point, your oil tank should have returned to it's correct level and the engine should be running normally. \\
-The transfer valve also allows oil to flow from the primary back into the crankcase if the sprocket shaft seal was leaking. \\ ((Hopper of the XLFORUM http://xlforum.net/forums/showthread.php?t=581947)) \\
-Excess oil gets into the primary through a bad crank seal or poor sealing of the oil pump. \\
-Keep in mind that drain oil from the top end also comes down the pushrod tubes and settles in the gearcase and down the holes in the cylinders into the crankcase. \\
-Any oil that gets in the gearcase floods the oil pump scavenge inlet and runs back into the crankcase oil slot. \\
-But, the oil was originally in the tank when the engine was shut off last. \\
-It gets to the crankcase thru normal top end drainage, the check valve or oil seal issues in the oil pump, flooding the oil trap, then to the crankcase, up the wall and into the primary thru the transfer valve. \\
-So plugging the transfer valve only addresses issues with oil getting into the primary from the crankcase but doesn't address excess oil getting into the crankcase. \\
-These are separate and equally important issues. \\
-**Main reasons for plugging the transfer valve**: \\
-  * To stop oil from filling the primary compartment when the engine sits for a while.
-  * To enable you to run separate oils in the primary and the engine without cross contamination. ((Iron Mike of the XLFORUM http://xlforum.net/forums/showthread.php?t=2077280&page=3))
-  * To run the primary dry. People do that to run belts (even though it's not necessary). ((Ferrous Head of the XLFORUM http://xlforum.net/forums/showthread.php?t=2077280&page=5))
-So there is technically no need to have the transfer function to remove sumped oil from the primary. \\
-However, if the crank seal blows out, you'll end up with a primary full of oil and lower oil flow to the engine due to half of the oil being in the primary. \\
-But that's a separate issue you'd have to fix with or without the transfer valve functioning. \\
-Quote from thefrenchowl of the XLFORUM ((http://xlforum.net/forums/showthread.php?t=774775&page=2)) \\
-<blockquote>H-D called this an "oil transfer valve" from its 1st application on the K model where indeed it acted as a suck valve for excess oil in the tranny due to a poor oil seal design on the engine sprocket. It had a tube attached to it, bent down towards the bottom of the sprocket. When oil level was normal in the tranny, it just sucked air. When the oil level went up, it submerged the tube and the vacuum in the crank cases sucked out the excess in the crank cases. The bad sealing idea was discarded in '54 and replaced with a proper lip seal and our unloved transfer valve. The guy who designed it is an unsung genius, cause it's real purpose, intended or not, wasn't discovered until the factory got rid of it in the late 70s. That's when they noticed that bikes which did not see constant use got various amounts of rust building up in the tranny, despite it having the small hole breather in the filler alloy cap and a special vent bolt installed on top of the tranny. A new problem they never experienced in the past engines. They then discovered there was little air circulation despite the 2 vents in these trannies and moisture stayed in to do the damage. In earlier engines, air is constantly being replaced in the tranny by the one way valve/crankcase vacuum and moisture can escape. So, if you use your bike daily, by all means, discard (the transfer valve). Personnally, I think it's a great idea and never experienced its failure in all the years I've been riding Iron Sporties or Ks, nearly 30 years now. If a part is in there, it's got a purpose. I've had too much oil in the tranny as anybody has experienced, but it's always been a seal failure, nothing to do with the transfer valve.</blockquote>
 ====== Removing the Transfer Valve ======
@@ Line 40: / Line 12: @@
 ====== Plugging the Valve / Hole ======
+**Note**: If you plug the transfer valve, it is advisable to also add a transmission / primary vent as well. \\
+The transfer valve has a dual function of moving out excess oil leakage from sit sumping and venting the primary compartment to the crankcase. \\
+(where the air is expelled along with crankcase pressure out the breather vent) \\
+Without a vent once the transfer valve is plugged off, primary venting is severely hindered if not bottled up entirely. \\
+It is possible to blow the sprocket seal, starter gasket or primary gasket without a vent to atmosphere over the primary or tranny. \\
-When plugging the transfer valve; \\
-With the dual function of moving excess oil leakage from sit sumping and venting primary compartment air, consensus says to also install a primary vent as well. \\
 See Venting the Primary below. \\
@@ Line 59: / Line 34: @@
-|  The transfer below valve below was packed with JB Weld to negate it's operation. ((photos by Jtrapass of the XLFORUM http://xlforum.net/forums/showthread.php?p=1095756#post1095756))  ||
+|  The transfer below valve below was packed with JB Weld to negate it's operation. ((photos by Jtrapass of the XLFORUM http://xlforum.net/forums/showthread.php?p=1095756#post1095756))  ||  Transfer valve removed, plug installed. ((photo by lofimofo of the XLFORUM http://xlforum.net/forums/showthread.php?t=1578633))  |
-|{{:techtalk:ih:oil:plugging_the_transfer_valve_1_by_jtrapass.jpg?direct&300|}}| {{:techtalk:ih:oil:plugging_the_transfer_valve_2_by_jtrapass.jpg?direct&300|}}|
+|{{:techtalk:ih:oil:plugging_the_transfer_valve_1_by_jtrapass.jpg?direct&300|}}| {{:techtalk:ih:oil:plugging_the_transfer_valve_2_by_jtrapass.jpg?direct&300|}}|{{:techtalk:ih:oil:transfer_valve_hole_plugged_by_lofimofo.jpg?direct&300|}}|
 ====== Venting the Primary ======
@@ Line 66: / Line 41: @@
 With the transfer valve plugged, the primary can't breath as it can with the transfer valve functioning. \\
 That air path would now be blocked. \\
-Technically, the primary has a vent other than the transfer valve being the clearance in the clutch cable where it enters the primary. \\
+Technically, the primary may have a vent other than the transfer valve being the clearance in the clutch cable where it enters the primary. \\
 That can also act as a vent as air can enter and escape there (the part where the actual cable goes into the threaded piece that screws into the clutch cable hole). ((Buck101 of the XLFORUM http://xlforum.net/forums/showthread.php?t=150130&page=4)) ((CrazyHorse of the XLFORUM http://xlforum.net/forums/showthread.php?t=150130&page=4)) \\
 There is slack (slop) where the cable end is pressure fitted ( by slack adjustment of cable) into the threaded piece. \\
@@ Line 74: / Line 49: @@
 **Installing a dedicated primary vent**: \\
-  * You can drill a tiny hole in the primary access plug. \\
+  * **You'd think you could use the hole in the primary access plug as a vent**.
-  * You can install a vent plug (like the 34744-77 tranny vent) through one of the holes on top of the cases, just in front of the rear engine mount bracket. \\ Those two bolt holes are used for the oil tank bracket (xlch model) or battery carrier bracket (xlh model). ((JBM of the XLFORUM http://xlforum.net/forums/showthread.php?t=146064)) \\ '77-up ironheads have this 3/4"x16 vent fitting factory installed in this location (transfer valve deleted in '77) \\ Short frame cases use 4 bolts and 3 studs to hold the rear mount to the cases. ((Dr Dick of the XLFORUM http://xlforum.net/forums/showthread.php?t=776527&page=4)) Long frame cases use 2 bolts and 3 studs. \\ On long frame cases the front two bolts were dropped to make room for the electric leg. \\ The XLH battery box / oil bracket was bolted in the vacated area. This is where the vent bolt for 77> was positioned. \\ These bracket bolts are in a position where trans oil don't seem to get tossed as much. So they don't eject much oil. \\ All 76< long frame cases (except 71XLCH) will accept the vent bolt in the 77> position. Bolt goes in the hole closest to the case parting seam. \\ Conversely, installing the vent bolt in any of the four short frame rear mount bolt holes usually results in drips from the vent.
+    * However, any non-tin cover bike with a blocked transfer will piss out the vent of the primary filler plug. ((Dr Dick of the XLFORUM http://xlforum.net/forums/showthread.php?t=776527&page=3)) \\ It's usually futile to retain the plug vent due to oil weep. Plugging that vent and installing a vent some where else is a good route.
-  * On <69 engines, you can drill and tap a hole at the top of the case on the primary side and tee into the vent line going to the oil tank. ((simeli of the XLFORUM http://xlforum.net/forums/showthread.php?t=776527&page=4))
+    * The primary filler plug part numbers are (34742-52A) for 54-70 and (34742-71) for 71 to 76. (Fridge of the XLFORUM http://xlforum.net/forums/showthread.php?t=776527&page=3))
+  * **You can use the 77-80 venting location on 70-76 engines**:
+    * You can install a vent plug (like the 34744-77 tranny vent) through one of the holes on top of the cases, just in front of the rear engine mount bracket.
+    * Those two bolt holes are used for the oil tank bracket (xlch model) or battery carrier bracket (xlh model). ((JBM of the XLFORUM http://xlforum.net/forums/showthread.php?t=146064)) \\ '77-up ironheads have this 3/4"x16 vent fitting factory installed in this location (transfer valve deleted in '77).
+    * Short frame cases use 4 bolts and 3 studs to hold rear mount to cases.
+    * Long frame cases use 2 bolts and 3 studs. ((Dr Dick of the XLFORUM http://xlforum.net/forums/showthread.php?t=776527&page=4)) \\ On long frame cases, the front two bolts were dropped to make room for the electric leg. The XLH battery box / oil bracket was bolted in the vacated area. This is where the vent bolt for 77> was positioned. \\ These bracket bolts are in a position where transmission oil don't seem to get tossed around as much. So they don't eject much oil. \\ All 76-earlier long frame cases (except 71ch) will accept the '77 vent bolt in it's intended location above the tranny.
+    * The bolt goes in the hole closest to case parting seam. \\ Conversely, installing the vent bolt in any of the four short frame rear mount bolt holes usually results in drips from the vent.
+    * However, if you use a longer hose, loop it up around the seat post and back down (as 2003-earlier Evos did), it shouldn't drip any oil. ((Hippysmack)) \\ (unless the sprocket shaft seal has blown)
+  * **You can tap a vent above the primary on 57-69 engines**:
+    * You can drill and tap a hole at the top of the case on the primary side and tee into the vent line going to the oil tank. ((simeli of the XLFORUM http://xlforum.net/forums/showthread.php?t=776527&page=4))
@@ Line 84: / Line 68: @@
 {{:techtalk:ih:oil:installing_a_transmission_vent_1_by_jtrapass.jpg?direct&300|}} ((photo by Jtrapass of the XLFORUM http://xlforum.net/forums/showthread.php?p=1082313#post1082313)) {{:techtalk:ih:oil:installing_a_transmission_vent_2_by_jtrapass.jpg?direct&300|}} ((photo by Jtrapass of the XLFORUM http://xlforum.net/forums/showthread.php?p=1082313#post1082313)) \\
+-1980 models use a fitting (34744-77) with a SAE 3/8" x 16 (x app. 7/16") bolt pattern that has a 1/4" hose nipple on the other end. \\
+{{:techtalk:ih:oil:1977_tranny_vent_pic3_by_on_.....jpg?direct&300|}} ((photo by on½.... of the XLFORUM http://xlforum.net/forums/showthread.php?p=5541672&highlight=transmission+vent#post5541672)) {{:techtalk:ih:oil:1977-1978_transmission_vent_by_hopper.jpg?direct&300|}} ((photo by Hopper of the XLFORUM http://xlforum.net/forums/showthread.php?t=209347&page=11)) \\
 \\

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