What is a Motorcycle Cooling System?

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A cooling system is required for any machine with an internal combustion engine. This is true for motorcycles as well.

Understanding how the cooling system works will help prevent riders from overheating their engines, which can lead to costly repairs. If you’re going to own a motorcycle, make this one of your priorities to understand before you start riding down the road.

What is the best way to cool your motorcycle? The first method of cooling a motorcycle is through air cooling. This involves natural wind passing through fins located on the cylinders. The second type of cooling is through water cooling. Coolant flows through thin plates that are attached to a radiator and is cooled naturally by wind. It is then recirculated in the engine.

The cooling system on a motorcycle is a pretty simple process but can have terrible consequences when it doesn’t work right. This article can explain in detail exactly how the cooling system works on a motorcycle as well as other information you’ll want to know as a rider.

How an Air Cooling System Works

Air cooling is probably the best way for a motorcycle’s to cool down. This feature is standard on most motorcycles. It’s efficient in a sense that it requires less parts to complete the cooling down of an engine. You’ll notice how a lot of motorcycle will have ridges, or fins, on the engine. These aren’t simply for looks, they actually serve a vital purpose in the functionality of the motorcycle (though they do look pretty cool!).

The combustion process within an engine is extremely hot. This is necessary for the engine’s pistons to move upward and downward to make the motorcycle turn. But the engine can’t get too hot because that will mean the structure of the metal components will begin to change and in turn can ruin the engine entirely.

Perhaps you have heard of the term “a seized engine.” This means that the pistons have fused to the walls of the cylinder. This usually occurs because they were heated up and then melted together. This is the end of the engine. It’s possible to get it fixed but it’s probably more economic to simply get a new engine entirely.

Here are the fins. The majority of motorcycle parts are exposed, so fins placed on the cylinder head and cylinder head can cool the engine down. These fins are generally made from aluminum because it’s light weight and has a higher heat transfer efficiency.

The fins are designed to cool the engine and allow the wind to flow through the motorcycle while it is being driven down the road.. Without the fins, the engine wouldn’t be able cool down as efficiently; the structure and fins can capture air better than the engine block.

How water cooling works

Water cooling works on motorcycles in a similar way to air cooling but with different methods. You’ll notice that a water cooled motorcycle engine looks a little different than others. This is because these types of bikes usually don’t have fins, instead they have what is called a radiator likely placed at the front of the engine block.

This system is more complicated, but it can withstand higher temperatures. Instead of fins outside, there are water jackets (or water trails) that run inside the engine around the cylinders. A reservoir is also attached to these water jackets.

The water pump is also known as the pump. It circulates and pushes water/antifreeze from the water jackets within the engine to the radiator, then back into it. This coolant passes through small plates in radiator circulation, which cools it down through the passage of wind. To cool the engine, the coolant is recirculated through the engine.

The thermostat is vital because it monitors engine temperature and regulates coolant flow. An extra fan is placed by the radiator and is turned on as a backup in case the coolant isn’t cooling down the engine fast enough. In the event that the radiator requires extra coolant, a reservoir can also be used.

Although this is a common term, “water cooled,” it’s not just water that circulates throughout the engine. For optimal temperature control, a 50/50 mix of water and antifreeze is required; the antifreeze has a higher tolerance for both freezing and extremely hot temperatures so you don’t have to worry much about riding your motorcycle in either condition. Plain water can cause engine overheating and reduce its tolerance to heat.

Which is better?

One common question you’ll hear in the motorcycle world is “Which cooling system is better?” There really is no right answer for this, it’s all just based on the rider and their preference. I’ll go through each option and help you decide which one is right for you.

First we’ll discuss air cooling. One of the biggest advantages of a system like this is it’s simplicity. Really the only parts that go along with this is the fins and that’s basically it. That means no coolant leaks and there’s less parts to maintain which means it’s cheaper, too.

Because of the simplicity of this system, your engine will warm up much faster when you’re trying to go for a ride. You don’t have to wait for the coolant to circulate and do it’s thing before reaching optimal operating temperature.

The biggest disadvantage of having an air cooling system is that it’s less efficient compared to a water cooling system. This, in turn, means you’ll have a higher risk of overheating the engine which could mean costly repairs later on. The engine’s fins are simpler than the rest, but it can be difficult to fix if there are too many. A chip here or there isn’t much of a worry, but a hard impact or drop with several fins broken could mean you need a new cylinder head or cylinder covers altogether.

Consider the many benefits of water cooling. Water cooling is much more efficient than how it regulates the temperature of a motorcycle’s engine. The regular heat transfer it’s constantly performing can assure a rider that their motorcycle is much less likely to overheat, especially if they’re riding a sports bike or using it for commuting.

Unlike air cooled, water cooled engines do have a lot of parts that you’ll have to take care of and maintain. This system is clearly more complicated than an air-cooled system. If you are stuck on the side of a car with an engine that overheats, there may be multiple reasons.

You’ll also need to stay on top of coolant levels; forgetting to top it off or letting it dissipate through constant cycling could also mean an overheated engine. Not to mention the possible coolant leaks you could encounter that can be sometimes difficult to pinpoint as to where they’re coming from.

Both water-cooled and air-cooled bikes have been my experience. Air cooled is much easier to come by since most motorcycles are built this way and it’s what I personally prefer because of the simple maintenance. It’s really up to you and what you’re okay dealing with on your motorcycle.

What Can Cause A Cooling System to Go AWOL?

Knowing how a motorcycle’s cooling system works is one part of the puzzle. Another part is knowing what could go wrong and why. If you find yourself with a motorcycle that’s constantly overheating, here’s what the problems may be.

We’ve touched up on the fact that several broken fins on an air cooled engine can cause it to overheat. We’ve also covered that not staying on top of coolant levels of a water cooled engine can also cause the engine to overheat. However, there are other ways your engine can heat up regardless of the engine type.

A lot of people don’t realize that oil has a lot to do with the cooling system. You could have all the coolant or wind you need to cool down the engine, but if there’s not enough oil the engine can still overheat and seize. The engine is kept at a lower temperature by the oil’s lubricating properties. Keep track of oil changes as they have a significant impact on engine health.

The engine can overheat if it is revved high or idles at high speeds. These conditions indicate that the engine is working overtime. This can be compared to your exercise routine: The more cardio you do, the more hot and sweaty you become. Similar principles apply to an engine. It’s okay to rev your engine, but if you’re constantly revving it you risk getting into that overheating stage (see my other article here to learn more about revving your motorcycle engine).

Unintentionally, your motorcycle may be idling excessively. You can adjust the idle screw. A normal idle should be between 700-1,000 RPM’s; anything above 1,500 RPM’s is excessive. To learn more about why your bike is idling so high, click here.

An overheated motorcycle engine can lead to frustration and costly repairs. But it happens to most of us riders and sometimes can’t be prevented because of some other underlying issues. Click here for more information about how to prevent your bike from overheating.

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