Differences

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--- techtalk:ref:carb06 [2019/06/11 21:41]
hippysmack created
+++ techtalk:ref:carb06 [2019/09/15 17:44]
hippysmack [Mods]
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 ====== REF: Carburetor, Intake Manifold & Exhaust ======
 ====== Aftermarket Air Cleaners and Modifications ======
+\\
+====== Air Cleaner ======
+===== Sub Documents =====
+  * [[techtalk:ref:carb06a|Homemade Air Cleaner Assembly]]
+See also [[techtalk:ref:engmech05#breather_vent_relocation|Breather Vent Relocation]] in the REF section of the Sportsterpedia. \\
+Some air cleaners are not set up to allow for the breather bolts into them and are only held on by the small front bolts. ((Shu of the XLFORUM http://xlforum.net/forums/showthread.php?t=146084&page=11)) \\
+For these breathers you would need to get a head breather kit and carb support bracket. \\
+The breather kit routes the head vents to the ground (or atmosphere) while the carb support bracket keeps the carb in the intake. \\
+\\
+Below is a breather vent re-direction on an EFI model. ((jcmellis of the XLFORUM http://xlforum.net/forums/showthread.php?t=1179974)) \\
+A small amount of crankcase oil was dripping into the A/C on a Figure Machine/Engineering air cleaner assembly. \\
+This air cleaner uses the stock Harley-Davidson breather tubes. \\
+There was no drip into the stock a/c but using the same breather tubes, it did with the afrtermarket A/C. \\
+This mod doesn't bypass the air cleaner. \\
+It doesn't solve the problem but rather just hides it. \\
+You still have the excess oil but this will arrange for it to run straight into the intake and away from the A/C. \\
+The problem is that the oil vapor needs to make a 180 degree turn, up and over the lip of the kit's bell-mouth, into the throttle body. \\
+A rubber hose would work, except the radius of the curve is too sharp due of the limited space inside the filter. \\
+It'd take some sort of semi-rigid tube. \\
+The Screaming Eagle Stage 1 air cleaner deals with the venting issue using two small preformed rubber tubes or hoses. \\
+The Figure Machine air cleaner utilizes the stock Harley breather hoses (63520-04). \\
+The hoses fit perfectly over the breathers. \\
+The only problem is that about 3/8" needs to be trimmed from both ends to fit the different internal dimensions of the filter/air cleaner. \\
+(The photo above shows the stock part on the left and the trimmed part on the right.) \\
+Once trimmed to size, the hoses are positioned at the mouth of the throttle body. \\
+{{:techtalk:ref:carb:hd_breather_mod_1_by_jcmellis.jpg?direct&300|}} ((photo by jcmellis of the XLFORUM http://xlforum.net/forums/showthread.php?t=1179974)) {{:techtalk:ref:carb:hd_breather_mod_2_by_jcmellis.jpg?direct&300|}} ((photo by jcmellis of the XLFORUM http://xlforum.net/forums/showthread.php?t=1179974))
+====== Running the Breather Hoses (91 and UP) ======
+===== How the umbrella ( head breather) valves work =====
+Read more about the breather system here: [[techtalk:evo:engmech07|Evo Crankcase Ventilation]]. \\
+The breather valves are located in in the rocker box with their air outlets in the heads. \\
+The breathers are one-way umbrella valves. \\
+These exit crankcase vapors through vents in the top of the cylinder head into the air cleaner. \\
+On each piston downstroke, crankcase pressure (air and oil mist) is routed up the pushrod tubes into the rocker box. \\
+Collected air pressure and oil mist in each rocker box is routed up into a sealed cavity in the lower portion of the box. \\
+This mixture passes up from underneath a rubber one-way valve sitting over the cavity inlet in each box. \\
+The oil is designed to separate from the air by hitting the underside of the umbrella valve and dropping back down into the lower end. \\
+Air pressure is designed to continue up past the umbrella valve and exit the hole in each head on the intake valve side.
+Air pressure escapes the head through the hollow bolts (one in each head) that hold the air cleaner mount. \\
+===== Vent Line Routing =====
+==== Above vs Below the Head Vents ====
+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. \\
+While it may look better or cleaner for the lines to be routed above the air cleaner; \\
+Doing so doesn't make for good functioning of the breather system. \\
+The air / oil that gets blown out is a combination of crankcase pressure and engine blowby. \\
+Blowby gasses produce a corrosive vapor which doesn't need to go back into the engine. \\
+It'll simply pool in the heads / vent lines. \\
+As you can see from the drawings below, expelled air leaves the rocker boxes by running downhill to get out the vent holes in the heads. \\
+If the vent lines are piped above the exit point in the heads, oil out of suspension will not drain back into the engine. \\
+The oil would have to run uphill to get from the heads to the rocker boxes and into the lower end. \\
+So there is no functional advantage to running the lines higher than the head vents. \\
+{{:techtalk:evo:engmech:91-03_sportster_head_breathing_2_drawing_by_hippysmack.jpg?direct&300|}} ((drawing by Hippysmack)) {{:techtalk:evo:engmech:04_up_head_breathing_drawing_2_by_hippysmack.jpg?direct&300|}} ((photo by Hippysmack))
+The air coming from the head vents has fine oil mist particles in suspension with it. \\
+When that air cools, the oil mist falls out of suspension and collects in the vent lines. \\
+Pointing the vent lines straight into the A/C (OEM) or down into a catch can allows the oil out of suspension to leave the vent lines. \\
+However, pointing the vent lines upward of the head vents allows oil out of suspension to collect in them. \\
+Once there is enough liquid oil in the upward breather tubes it will act just like the trap under your sink. \\
+It may block air from getting out until the engine (on startup) builds enough pressure to push the liquid and bubble up to the top. \\
+So it may affect crankcase pressure slightly until the lines are cleared. \\
+Or the trapped oil may simply be blown out the vent lines in globs. \\
+Vent lines mounted low allows oil to leave the heads. \\
+{{:techtalk:ref:carb:breather_lines_mounted_low_by_ixl2relax.jpg?direct&300|}} ((photo by IXL2Relax of the XLFORUM http://xlforum.net/forums/showthread.php?t=1051311&page=46)) {{:techtalk:ref:carb:breather_lines_mounted_low_by_beuz.jpg?direct&300|}} ((photo by beuz of the XLFORUM http://xlforum.net/forums/showthread.php?t=11697&page=582))
+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))
+====== Breather Bolts ======
+Kuryakyn banjo bolts: \\
+{{techtalk:ref:engmech:kuryakyn_banjo_breather_bolts_1_by_mick42.jpg?direct&300|}} ((photo by mick42 of the XLFORUM http://xlforum.net/forums/showthread.php?t=2074032&page=2)) {{techtalk:ref:engmech:kuryakyn_banjo_breather_bolts_2_by_mick42.jpg?direct&300|}} ((photo by mick42 of the XLFORUM http://xlforum.net/forums/showthread.php?t=2074032&page=2))
+====== Pics of Air Cleaners ======
+|  Caddy Ornament. ((photos by Lone Rider of the XLFORUM http://xlforum.net/forums/showthread.php?p=5712103&highlight=heel+toe#post5712103))  ||
+|{{:techtalk:ref:carb:caddy_ornament_ac_1_by_lone_rider.jpg?direct&300|}}|{{:techtalk:ref:carb:caddy_ornament_ac_2_by_lone_rider.jpg?direct&300|}}|

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