harley evo crankcase vent

Harley Evo Crankcase Vent – Pros and Cons of Different Options

Maintaining proper ventilation of your Harley Davidson’s bottom end is key to preserving its performance. Deter the build up of foreign elements and vapor with a range of options for crankcase ventilation available today.

Whether you are an experienced biker or a novice, this article is sure to be informative and provide valuable insight into the different Harley Evo Crankcase Vents available. We will discuss each option’s relative strengths and weaknesses as well as some personal reviews from riders who have already tried them out. Keep your bike running at its peak performance for longer by reading our comprehensive guide on these exhausts.

Different Options for Venting the Crankcase

There are several options to ventilate the crankcase of a Harley Evo, each with their own pros and cons. The most popular choice is to either replace your existing breather valve for another one or use a breather bolt instead.

These valves and bolts allow for unrestricted airflow, but at the same time serve as a barrier to prevent dust and oil from entering your engine. The Hayden Kank Vent Plus Valve Breather is an excellent example of this technology – it works by replacing your normal breather valve with a one-way closure that helps keep out unwanted particles which could damage or contaminate the system.

An economical and easy way to filter your exhaust ventilation is with a K&N air filter. Many riders find this option highly effective, while others prefer an air filter mounted on their bike. Either way, these are great solutions for keeping your engine running smoothly.

Though sometimes seen as a last resort, some riders prefer to exhaust the crankcase fumes through tubing and onto the ground. While this may seem simple yet effective for certain people, it can lead to an unsightly oily mess on both your bike and you.

Pros and Cons of Each Method

If you want to ensure that no debris or oil will enter your engine, then a breather bolt or replacing the stock breather valve are both excellent options. Unfortunately, they can be costly compared to other venting methods like using a filter and hose.

A filter is an effortless and affordable solution for most bike riders, although it can become blocked with buildup over time and decrease its potency.

Expelling the crankcase’s oil to the ground through a hose is an economical and straightforward solution, albeit it can splash onto your motorcycle as well as yourself. Furthermore, some owners may deem this visually unappealing.

User Experiences

Riding enthusiasts have experienced great results from utilizing different crankcase ventilation methods. Take one rider on an HD Forums thread, who installed the Hayden Kank Vent Plus Valve Breather and not only enjoyed the difference in engine sound but was also pleased to learn that a one-way valve kept destructive debris away from his motor. Despite this rider’s satisfaction with the product, however, he noted being unable to accurately measure any power gain.

Another rider on the same forum installed an S&S breather valve and experienced a substantial improvement immediately. The engine became quieter since one gear was removed from the case, as well as there being no oil escaping from the vent.

To help vent the crankcase, some riders have tested unique solutions. One such example is running a hose from the air cleaner to a Krank Vent and further along the right side of their frame. The end portion of this setup was then fitted with an additional piece of hose that pointed downwards near the front part of its frame – letting any excess fumes seep out close to ground level.


If you’re looking for ways to vent the crankcase on your Harley Evo, you have plenty of choices. A breather bolt or a valve that replaces the stock breather are both good options since they prevent debris and oil from getting into the engine. Another cost-effective approach is using a filter – an uncomplicated solution that works well for most riders.

Venting the crankcase to the ground using a hose may be cost-effective, but it also has its drawbacks: splattering oil and debris back on your bike or you. Ultimately, what works best comes down to a rider’s budget limits and personal preferences.


Below are some frequently asked questions on the Harley Evo crankcase vent:

What is a Harley Evo crankcase vent?

By releasing extra pressure and gases from the engine’s crankcase, a Harley Evo Crankcase Vent safeguards your motor against harm due to an accumulation of too much force.

How does a Harley Evo crankcase vent work?

Outfitted with a valve or filter, the Harley Evo crankcase vent allows any extra pressure and gases to be safely expelled from the engine. These vapors are then guided through a hose to either an air breather or filter before they can finally float away into our atmosphere.

What are the benefits of using a Harley Evo crankcase vent?

By installing a Harley Evo crankcase vent, you can reduce rising pressure inside your engine to avoid damage to its components and lessen the chances of oil leaks that are caused by too much pressure. With this upgrade, you will be enhancing the overall performance of your vehicle so it runs more efficiently.

How do I install a Harley Evo crankcase vent?

Swapping out your stock breather system for a Harley Evo crankcase vent can be straightforward, depending on the setup. Generally, you’ll remove the old system and replace it with the new one. However, some systems may require additional hoses or fittings to complete installation properly.

What are some popular Harley Evo crankcase vent options?

When it comes to Harley Evo crankcase venting, you have three options: the Hayden Kank Vent Plus Valve Breather, clone K&N Filters or S&S reed valve breathers. It’s important that you do your due diligence and select a system that is compatible with your bike’s model and year.

Do Harley Evo crankcase vents improve engine performance?

Installing a Harley Evo crankcase vent can not only protect your engine from damage, but could also provide an uptick in performance. It all depends on the particular system you use and how well-maintained your engine is.

Can I install a Harley Evo crankcase vent myself?

If you have some mechanical know-how, installing a Harley Evo crankcase vent can be an easy do-it-yourself project. Just remember to follow the manufacturer’s directions precisely and make sure it is compatible with your bike model and year—otherwise the system won’t work correctly. For those who don’t feel comfortable performing this task themselves, it’s always best to hire a professional mechanic for installation.

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