Excessive oil coming out of the breathers on your Harley Davidson S&S 124" build can be a sign of several potential issues. Here are a few possible causes to consider:
Overfilled Oil System: One of the most common reasons for oil puking out of breathers is an overfilled oil system. When the oil level exceeds the recommended limit, it can create excessive pressure within the engine, causing oil to escape through the breathers. Ensure that you have not overfilled the oil tank or crankcase.
Blow-by: Blow-by occurs when combustion gases leak past the piston rings and enter the crankcase. This can happen due to worn or damaged piston rings or cylinders, excessive cylinder wear, or inadequate piston-to-wall clearance. Blow-by increases crankcase pressure, leading to oil being forced out through the breathers.
High Oil Pressure: If the oil pressure in the system is too high, it can force oil past the breather valves. This can happen due to a malfunctioning oil pressure relief valve or an oil pump that is delivering oil at a higher pressure than necessary. It's important to check the oil pressure using a gauge to ensure it falls within the manufacturer's recommended range.
Restricted Breather System: The breather system in your motorcycle allows crankcase gases to escape while preventing oil from being discharged. If the breather system becomes restricted or clogged, it can cause oil to back up and escape through the breathers. Check for any blockages or restrictions in the breather system, including breather tubes, filters, or vents.
Other Engine Issues: Several other engine problems can contribute to excessive oil coming out of the breathers. These include worn valve guides, excessive valve stem seals, worn or damaged camshaft bearings, or excessive cylinder head oil drain-back. If any of these components are faulty or worn, it can lead to increased oil consumption and blow-by.
It's important to have your motorcycle inspected by a qualified mechanic who can diagnose the specific cause of the oil puking issue. They can perform a thorough examination, including checking compression, oil pressure, and inspecting various engine components, to determine the root cause and recommend the appropriate repairs or adjustments.