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techtalk:evo:engmech07 [2020/06/23 19:47] hippysmack [Sub Documents] |
techtalk:evo:engmech07 [2020/08/08 23:21] hippysmack [Late 1984-1990 Engine Breathing] |
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| ====== Late 1984-1990 Engine Breathing ====== | ====== Late 1984-1990 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. \\ | ||
| * 86-90 engines continued the breather baffle tube system from previous year models incorporated into the cam cover in the area behind the 86 style oil filter. | * 86-90 engines continued the breather baffle tube system from previous year models incorporated into the cam cover in the area behind the 86 style oil filter. | ||
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| ====== 1991-2003 Engine Breathing ====== | ====== 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. | * 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)) | * 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)) | ||
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| ====== 2004-Present Engine Breathing ====== | ====== 2004-Present 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 2004 the MoCo made some changes to the umbrella valve configuration. \\ The umbrella was retained but now inside a plastic housing with a pre-umbrella oil separating screen. \\ Each 'breather valve' is assembled into a plastic fitting that is sealed over the outlet hole in the lower rocker box to the head breather bolt. \\ The new breather valves were also accompanied with new style hollow air cleaner mounting bolts for the pressure to escape. | * In 2004 the MoCo made some changes to the umbrella valve configuration. \\ The umbrella was retained but now inside a plastic housing with a pre-umbrella oil separating screen. \\ Each 'breather valve' is assembled into a plastic fitting that is sealed over the outlet hole in the lower rocker box to the head breather bolt. \\ The new breather valves were also accompanied with new style hollow air cleaner mounting bolts for the pressure to escape. | ||
| * The new bolts are the same thread size as previous. \\ But instead of a simple hex, it also has a shoulder past the hex for an O-ring to be fitted between the hex head and the air cleaner. | * The new bolts are the same thread size as previous. \\ But instead of a simple hex, it also has a shoulder past the hex for an O-ring to be fitted between the hex head and the air cleaner. | ||
