4 Common Harley Davidson Twin Cooled Engine Problems & Solutions 2024

Dealing with Harley Davidson twin cooled engine problems is frustrating and expensive to deal with.

This has made many people dislike the Harley Davidson engine.

Since Harley Davidson announced the twin cool engine, a lot of people have chosen to use it on their bikes because of the reputation Harley Davidson has in the technology market.

But recently, a lot of the Harley Davidson twin cool engine users have complained about the various problems they are facing when using the engine.

Problems such as the plastic cam chain socket which will eventually weaken because of the grinding and the frequent contact of the rubber cam shoe.

This article is not meant to say something bad about the Harley Davidson twin cool engine but to enlighten our readers of the likely problems they will face when using the Harley engine for their motorcycle and the likely solutions.

Without further ado, let’s get in to know more about the Harley Davidson twin cool engine.

What is a Harley Davidson twin-cooled engine?

Harley Davidson’s twin-cooled engine was launched in early 2014 when the 2014 Harley model range bike was launched too. Two twin cooled engines were launched; the 103 and the 110 engines.

What Harley Davidson means by the Twin-Cooled engine is that coolant and water are being used to cool the top of the engine, which is close to the exhaust pipe where the heat is mostly generated.

This is an amazing development and it was designed to comfort the riders and not to be found guilty of the emission laws in some countries.

Many people have mistaken the twin cooled engine to mean Harley has made it water-cooled just like the V-Rod engine, this is not so.

The twin cool engine still cools the barrels using air cooling system and has the same structure as the previous Harley engines.

The only notable changes is that the radiator is hoisted between the front twin rim support and an electric pump organizes coolant circulation.

Fluid cooling enables the contraction to rise to 10.1:1 which improves the torque. Furthermore, it should be marked out that Twin cooled, Ultra Classic engine and the popular CVO variant is not available in Australia.

Maybe the device will someday work its path into other prototypes, but with the portable radiator emitted in the front, at the back of the fairing, this will be hard to induct into the URK but might be logical in the half-done Street Glide.

Practically the recent engine is just like BMW’s little “Wasser boxer”. It’s partially water-stimulating so that the important parts of the engine are left intact.

How does the twin cool engine work?

Harley Davidson designed the twin cooled engine to help cool your Harley Davidson motorcycle when it’s is overheating, when your motorcycle overheats, it tends to burn some important part of the engine.

Because the twin can engine shoes are made of plastic, they tend to wear out faster when the engine overheats are this is why the Idle is designed to help keep the engine from overheating.

Again, the twin-cooled engine does not mean the engine has a two-cooling system, but the top head of the motorcycle has a radiator and a cooking system and flows back and forth to keep the engine cool even when it is still working.

The cylinder and the motor transmission are air-cooled and this is the reason why it is called a twin cool engine.

You will have fluid cooling the head of the engine where combustion happens and the piston and the cylinder resting on the motor also needs the air traveling over it plus the radius also needs air over it even though they have fans, so you need to keep moving and when you are not moving name sure to turn off the ignition and make the motorcycle rest.

Features of Harley Davidson twin cooled engine

The new twin cooled Harley Davidson engine has a lot of new features different from the previous version of engines, and in this section, we will be talking about the new features of the engine.

01: Eight valves

The twin cooled engine has eight valves, four more than the former engine. Fours valves are positioned on each cylinder.

The increased number of valves is to allows air to flow in and flow out of the engine cylinder easily.

The air generated by the valves helps push the engine pistons up and down.

02: Two Cylinders

The cylinder functions as a vacuum through which the engine piston travels, impelled to the energy produced from the combustion of the fuel/air mixture in the engine combustion chamber.

In the twin cool engine, the sides of the cylinders are opened to the airflow, to give the primary means of cooling the engine.

03: 50% Increase in exhaust flow

As a result of the increase in the number of valves, the rate at which exhaust flow has also increased by 50%, this is easily understandable because the valves were increased from four to eight.

The exhaust valve functions very well in clearing the path through which the exhaust will pass and prevent the engine from overheating.

04: Improved Cooling System:

The cooling system was improved and it was noticeable as the head of the engine now has air flowing over and the piston also gets cooled, so you don’t have to be afraid your engine overheats when you are stalked in the traffic.

05: Increased Torque:

The Harley Davidson twin-cooled engine has more torque than the predecessor and this gives the motorcycle more horsepower.

Torque is a wrenching force that communicates to the engine’s rotational pressure and gauges how much of the wrenching force is used when the engine exerts itself.

06: Increased Fuel Economy:

The engine is designed to gauge the fuel combustion and reduce it to the barest minimum. This is an important aspect to reduce the rate at which the engine consumes fuel.

Harley Davidson Twin Cooled Engine Problems

Everything that has advantages has disadvantages, so the Harley Davidson twin cool engine also has some problems.

01. Low Oil Pressure

This is a common problem of the twin cooled engine.  If your engine is low on oil, it tends to act strangely and might give you some headache.

The engine might refuse to start as a result of low oil pressure, because if your engine works without oil inside, it may cause some damages.

02. Cam Chain Tensioner

The problem with the chain tensioner is one of the popular Harley Davidson twin cooled engine problems. The problem arises as a result of the design and the head cover made of plastic.

Harley has therefore made room for the solution to the problem. You will have to replace the headcover, although this set is quite costly, you’ll someday have to displace the stock chain to avoid this problem.

03. Engine Shuts Off

Although various parts can turn off the engine haphazardly, riders have complained that a faulty temperature detector can cause the issue.

If fixing the temperature sensor doesn’t fix your engine shutting down issue, then check for spoiled vacuum lines. These vacuum lines get damaged over time, causing the engine to stall.

And lastly, check your engine fuel pressure control, or FPR for short.

04. Starting Issues

It’s not often easy to discover what’s wrong with the engine when it refuses to start. As mysterious as this problem might be, examine the starter relay. If it stops working, the engine will not run. After repairing this part, the cycle should work again.

Possible solutions of Harley Twin Cooled Engine Problems

Low Oil Pressure

To fix the issue of low oil pressure, you need to refill your oil tank. But firstly, remember to find out the type of oil your engine uses.

Once you know that, drain the previous oil in the engine. After that, put in your new filter.

Next thing is to replace your washer if it got destroyed. After repairing it, put in the drain plug and pour the new oil.

Cam Chain Tensioner

To fix this issue, replace the entire unit. Although the kit is very expensive, replacing the kit will help you solve the problem

Engine Shuts Off

If your motorcycle engine suddenly shuts off, inspect the temp detector. This is not as difficult as you think, but it will take some time to rip it off.

Firstly, you have to unload the seat and then detach the battery terminal. Once you have done this, discard the gas tank. With the gas tank out, you will be able to put another old temp sensor.

Starting Issue 

Replace the starting relay, completely take the motorcycle seat out and disconnect the negative terminal, rip off the former relay, and insert the new one.

Pros and Cons of Harley Davidson Twin cooled Engine


  • Increased number of valves
  • Increased power and torque
  • Revamped cooling system
  • Free exhaust flow
  • Reduced heat
  • Lesser fuel combustion


  • More number of parts
  • High maintenance cost.

Maintenance tips of the Harley Davidson Twin cooled engine

Below are some maintenance routines that you have to carry out on your engine to keep it working and save you some maintenance money

1: Coolant Service

This is needed every at every 150,000 miles your engine travels, coolant service is important to maintain the engine running in severe temperatures.

This will protect the passengers and even the vital elements near it from overheating.

2: Change your Spark Plugs

If you don’t want any problem with your twin cooled engines, reinstating the spark plugs when you travel 100,000 miles is important.

Changing the plugs ensures high efficiency and durable performance of the engine.

3: Change your Engine Oil

For effective engine performance, please change your engine oil regularly. Changing the oil and the oil filter is a great maintenance task that shouldn’t run off your schedule.

However, it relies on various factors, every 5000 to 6,000 miles is ideal to do it.

4: Engine Air Filter

Purchasing a new air filter every 13,000 miles enables the engine to procure clean air that is important for its combustion process. This will even make your motorcycle engine consume less fuel.

5: PCV Valve

Maintaining the PCV valve in good constraint every 100,00 miles is an essential maintenance duty. This eliminates hazardous oil gases from the engine and keeps the engine in a perfect working position for a long time.

Frequently Asked Questions of Harley Twin Cooled Engine

1: What are the bad years for Harley-Davidson?

1969-1981 are the worst year that Harley Davidson has experienced in their production, so many bikes with bad quality were produced.

2: How long does the Twin cool engine last

It should last about 150,000-200,000 miles if you maintain the engine properly.

3: Does the Twin cooled engine worth the money

Yes, the engine is worth every penny it costs, the design and the performance is too notch and easy to maintain.

4: Is the twin cooled Harley Davidson engine reliable: 

There are a lot of flaws in the Twin Cooled engines. Enough issues to scare you and make you reconsider it before buying one.

The main issue of the Twin cool engine of the Harley Davidson engine is probably the design facet of the twin cool chain system.

5: Why does the Harley twin cooled engine shake?

It is normal for the engine to shake when in motion. Harley engines often shake when moving. However, this might look like a design drawback, you don’t have to worry about it as nothing will happen to the engine.


While Harley’s twin-cooled engine problems are almost unavoidable, understanding the most common problems and their valid solutions beforehand will enable you to tackle any problem.

If the problem persists, you can contact an expert that you trust to get recommendations on what to do.

However, if you obey our maintenance recommendations fully, you might not have any problem with your engine.