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Harley Oil Breather Problems? I Have The Answer!

by

Chase Manhattan

Chase Manhattan Avatar
Owner and Editor at The Wrench Network

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Hey y’all, it’s Chase Manhattan! I’m a life-long automotive and motorcycle enthusiast with a knack for diagnostics that I hope to share with you! Lately, I’ve been running my own motorcycle rental business, which you can read about here, and it has been a great experience that has allowed me to own numerous bikes that I probably couldn’t justify otherwise. Plus, it’s been a great way to experience new places while on vacation. If you haven’t heard of them before, I definitely recommend checking out the Riders-Share platform if you get the itch to ride while away from home, or if you want to explore a cheaper way to own and ride motorcycles!

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In the world of motorcycling, Harley Davidson has established itself as a prominent name. However, like any mechanical device, it’s not immune to certain issues. One such common issue among Harley owners is the oil pouring out from the crankcase breather.

If you’re dealing with oil coming out of the crankcase breather on your Harley, you’ve come to the right place. This article will provide an in-depth analysis of the possible causes, solutions, and preventive measures for your Harley that’s puking oil.

You’ll need this later: The Best Oil For Harley Davidson Motorcycles Gets Revealed

What Are The Most Common Harley Oil Breather Problems?

close up picture showing a Harley after a Breather Bypass

The primary concern that Harley riders face is oil leakage from different parts of the motorcycle. Depending on the model you own, you might experience:

  • Oil Coming Out Of The Crankcase Breather
  • Oil Coming Out Of Your Air Filter
  • The Umbrella Valves Failing

Let’s break down each of these problems.

Oil Coming Out Of Crankcase Breather

The most common issue Harley owners face is oil leaking from the crankcase breather. This problem can arise due to several reasons such as:

  • A Clogged Or Damaged Breather Or Hose
  • Misalignment Of The Ball Seating Position
  • Overfilling Of Oil In The Crankcase
  • A Malfunctioning Oil Filter
  • An issue internal to the oil pump

To fix this, it’s recommended to replace the ball and spring, polish the ball seat, and replace the oil filter. (But there can be other causes, this is just good practice)

Oil Coming Out Of Your Air Filter

Another issue Harley Davidson owners often encounter is oil leaking from the air filter. This can occur due to the excessive oil levels in the crankcase, resulting in oil being pushed out through the breather, eventually reaching the air filter. It is worth noting however, there is a normal level of blow by that’s present in all combustion engines. If there’s enough to come out of the filter however, that’s where the issue lies.

To remedy this, ensure that your motorcycle oil level is maintained at an optimal level. Also, conduct regular checks and cleanups of your air filter.

Read next: Harley Oil Light On Before Starting? I Got You Covered

The Umbrella Valves Are Failing

In Harley models, the umbrella valves play a crucial role in maintaining the pressure balance within the engine. However, with time, an umbrella valve can harden and fail, leading to oil leakage issues. This is typically signified by oil leaking from the rocker covers (most commonly found around the right cam cover gasket).

To prevent this, it’s recommended to check these valves regularly and replace them if necessary.

Let’s Recap: How Does The Breather System Work?

Basic infographic diagram showing how the oil breather system works on Harley Davidson motorcycles
As an aside, it’s worth noting that some riders may prefer bypassing the system entirely; they can opt for an external breather instead. (In lieu of a recirculatory system, like the one that comes stock on most bikes)

The breather system in a Harley Davidson motorcycle is designed to manage the pressure within the crankcase and prevent oil leakage. It allows fresh air to enter the crankcase, replacing the harmful gases and fumes.

However, when the system fails, it can lead to oil leakage from various parts of the motorcycle, including the crankcase breather and the air filter.

Is It Necessary?

The breather system is an integral part of a Harley Davidson motorcycle. It helps maintain the pressure balance within the engine, prevents the buildup of harmful gases, and ensures the smooth operation of the motorcycle. Therefore, it’s not only necessary but essential for the optimal performance of your Harley Davidson.

Also, as a rule of thumb for me personally, I recommend you familiarize yourself with my technical resource catalog before attempting any significant procedures:

> Torque Specs for Harley Davidson: Ultimate Guide (PDF)
> Complete Harley Davidson Tire Size Chart (PDF)

Can You Remove The Oil Breather Entirely?

It’s not recommended to remove the oil breather system entirely since the system plays a crucial role in maintaining the pressure balance within the engine and preventing oil leakage. Removing it can lead to severe engine damage and other mechanical issues.

Read more here: Harley Breather Bypass: Should You and How?

Brief Overview of The Breather Bypass Procedure

Example of a breather bypass kit for Harley Davidson motorcycles
Pictures is new tubing and breather bolts included in most bypass kits.

The breather bypass procedure involves rerouting the breather hose from the air cleaner to a separate catch can or filter. This prevents the oil mist from getting into the air cleaner, thus reducing the risk of oil leakage.

However, this procedure should only be performed by a skilled mechanic, as it involves significant modifications to the motorcycle’s engine.

Pros and Cons of Bypassing The Breather System

While bypassing the breather system can help reduce oil leakage, it also has certain drawbacks.

Pros:

  • Reduced Risk Of excess Oil Leakage
  • Improved Engine Performance
  • Prevents Oil Mist From Getting Into The Air Cleaner

Cons:

  • Requires Significant Modifications To The Engine
  • Can Lead To Engine Damage If Not Done Correctly
  • Not Recommended For Inexperienced Riders Or Mechanics

How Does This Affect Performance?

Bypassing the breather system can improve the performance of your Harley Davidson motorcycle by reducing the risk of oil leakage. However, if done incorrectly, it can lead to engine damage and other mechanical issues.

But, you should know: Harley Oil Pressure Problems? Read This! (Help Is Here)

Does It Affect Reliability?

While bypassing the breather system can improve the performance of your motorcycle, it can also affect its reliability. If the bypass procedure is not done correctly, it can lead to engine damage and other mechanical issues, reducing the reliability of your motorcycle.

In conclusion, while Harley Davidson motorcycles are known for their performance and reliability, they are not immune to issues like oil leakage from the crankcase breather. Regular maintenance, timely checks, and a good understanding of the motorcycle’s breather system can help prevent these issues and ensure the smooth operation of your Harley Davidson.

Hot topics:
> A Shootout For The Most Reliable Harley Engine (What Is It?)
> Harley Davidson Frame Types And Model Codes Explained
> Harley Engines by Year: The Legacy of American Motorcycling
> Complete Harley Davidson Tire Size Chart (PDF)
> Shovelhead vs Panhead: A Harley Davidson Engine Showdown
> Does Harley Davidson Make Automatic Motorcycles? Yes And No

Frequently Asked Questions

Why does my Harley Davidson spew oil from the breather?

This can happen due to overfilling the oil tank, worn piston rings, or a clogged breather system. Overfilling increases crankcase pressure, forcing oil out. Worn piston rings or a clogged breather disrupt proper air pressure balance, causing oil to be pushed out.

What are common symptoms of Harley oil breather problems?

Common symptoms include excessive oil leaking from the air cleaner, oil misting onto the engine or surrounding parts, decreased engine performance, and possibly increased engine temperature.

How can I fix oil coming out of the breather in a Harley Davidson?

Start by checking the oil level and ensuring it’s not overfilled. Clean or replace the air filter if clogged. For more persistent issues, inspect the piston rings and breather system for any damage or clogs.

How often should the breather system be checked in a Harley Davidson?

It’s advisable to check the breather system during regular service intervals or if you notice any symptoms of breather problems.

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