Top Three Kawasaki KFX 50 Problems And Their Solutions

Kawasaki launched their KFX 50 as their initial four-wheeler, mainly for kids. It is a QUAD bike, and kids and teenagers will find it outstanding. Its beginner-friendly design and performance make it an excellent gift for kids. 

Parents have reported a few Kawasaki KFX 50 problems as their kids rode it. Mostly, the quad bike suffers from engine throttling issues. You will also see engine overheating, malfunctioning battery, and speed reduction after a while. 

Kids will not appreciate these problems in their four-wheeler. So, you must find the issue accurately and fix it to offer children a great riding experience. 

Kawasaki KFX 50 Problems And Their Solutions

Kawasaki KFX 50 Problems Explained And Solved:

Kawasaki KFX 50 Problems Explained And Solved

Kawasaki KFX 50 is a perfect starter quad and ATV for kids and teenagers. It has a 49.5cc engine and collar with the Continuously Variable Transmission (CVT) for speed and performance control. So, parents can control their kids’ riding experience and safety with KFX 50. Nonetheless, KFX 50 has a few big problems that often ruin the riding fun. 

Engine Overheating And Throttling Issue:

Engine Overheating And Throttling Issue

The major problem of the Kawasaki KFX 50 is its engine overheating and throttling. Many parents have reported that their kids have felt uncomfortable on the seat due to excess heat. They said that the engine was getting too hot. As a result, the heat spreads across the ATV, and the seat feels uncomfortable with the added heat. 

According to Kawasaki’s standard, ATV engines should perform between 120-180 degrees Fahrenheit. If the temperature goes beyond it, overheating can be a problem. If it persists, it can damage the parts soon. 

What’s more, the engine often suffers from throttling and performance reduction. A reviewer in the FixYa forum reported that his KFX 50 would start and idle fine. However, after a few minutes, the engine stopped working, and the ATV reached a standstill. (Source:  Many users have reported the same problem. Plus, engine overheating and throttling caused a loss of speed big time. 

Causes Of Engine Overheating And Throttling:

Causes Of Engine Overheating And Throttling

The engine in your Kawasaki KFX 50 can be due to multiple reasons. Usually, the engine overheats when its fan starts malfunctioning. Plus, there can be a low level of coolant on the radiator. So, you must scrutinize the ATV and address the issue. 

  • The cooling fan may malfunction and not provide enough air to the engine. As a result, the engine won’t get enough ventilation to cool down. 
  • The engine oil and coolant may be lower than the standard level. Also, you may need to use a different coolant. 
  • Running the ATV at low speed will also cause overheating. Kids performing too much idling of the vehicle also causes throttling. 
  • Finally, overload and worn-out spark plugs can cause problems as well. The ATV is made to bear 250 lbs weight. If you put more weight on it, the engine will have to work extra, and so will overheat. 

Four primary reasons for engine throttling and overheating in Kawasaki KFX 50. So, you must apply different techniques to troubleshoot it, depending on the problem route. 

Tips On Solving KFX 50 Overheating And Throttling Issue:

Tips On Solving KFX 50 Overheating And Throttling Issue

We have said that there’re four reasons for engine overheating. So, inspect the actual KFX 50 problem and work accordingly. 

Fix Or Replace The Cooling Fan:

Check the fan carefully as you run the KFX 50 engine at full speed. If the fan is working correctly, you should hear a sound coming out of it. Plus, you should feel air ventilation right underneath the seat and close to the engine. 

When the fan stops working, you won’t feel the ventilation. Plus, the engine will overheat too quickly. 

  • Check the wiring of the fan. If there’s any loose connection, you should reconnect it. In most cases, fixing the wires will solve the problem. 
  • Sometimes, the blades of the fan can be damaged or bent. At this moment, use a wrench to fix the blade. If it doesn’t work, replacing the fan is necessary. 

Kawasaki KFX 50 coolant fans will cost you $20 to $30 for replacement. So, you should be able to replace the damaged or malfunctioning fan quickly. 

Ensure Proper Engine Oil And Coolant Level:

Next, check the engine coolant and oil for KFX 50. Kawasaki recommends using the Kawasaki Aluma-Cool Engine Coolant. Kawasaki suggested it reduces the engine temperature and boosts its speed and performance. 

You should check if you are using a suitable engine coolant. If not, choose the recommended one. Plus, you may use an ethylene glycol-based antifreeze. You need to mix it with 50% or 60% water. If you use the recommended coolant, it comes pre-diluted. So, you can use it directly in the engine without mixing water. 

Moreover, you may use a dipstick to check the engine oil and coolant level. If the oil level is too low, you must apply the new ones. 

Stop Overloading And Running KFX 50 At Low Speed:

Stop Overloading And Running KFX 50 At Low Speed

Finally, ensure that the quad bike doesn’t compass its recommended weight level. When you ride the vehicle within its suggested weight limit, the engine doesn’t need to take extra pressure. So it will work efficiently without getting overheated. 

Next, you should inspire your kids to run the KFX 50 at optimal speed. When they run at low speeds, they can overheat the engine. Thus, driving the vehicle at a higher speed will increase engine efficiency. At times, you may unknowingly turn on parental control. It includes the following ones:

  1. Keyed ignition 
  2. Throttle limiter 

So, check them and eliminate parental control. You can adjust the throttle limiter to increase KFX 50 speed. 

Changing The Carburetor:

If you see KFX 50 engine overheating and stopping working frequently, the problem might be with the carb. The engine stops working and returns to its total capacity after resting for 10 to 20 minutes. Then, the problem must be with the carburetor. 

It would help if you replaced the stock carburetor. Kawasaki uses their auto-choke carb for KFX 50. Plus, a user suggested replacing it with the Honda CT70 Carb. Also, sometimes riding the quad bike with the gas cap off can fix it. 

Loss Of Speed:

Many users have reported a loss of speed for their Kawasaki KFX 50. They said their kids got full speed for a couple of minutes after starting the engine. Then, the vehicle will lose its speed. As the rider keeps riding the quad bike, the speed gradually reduces. 

Why KFX 50 Losses Its Speed:

The speed loss is a common Kawasaki KFXX 50 problem. It might happen for various reasons. These include:

  • Maybe parents have turned on the throttle limiter. Also, the Continuously Variable Transmission (CVT) collar may be limited. Often, people need to remember it after applying the speed limiter. 
  • The engine isn’t receiving enough energy. What’s more, the fuel can be inferior. If the gas used in the vehicle is below-grade, the engine fails to deliver its correct performance. 
  • Clogged air filters and turned-off fuel taps can be responsible too. At that time, the engine starts but fails to continue riding at its expected speed. 

Tips On Solving The Speed Loss Problem:

Tips On Solving The Speed Loss Problem

First, check the throttle limited and CVT collar. If you find them in a limited setting, adjust the throttle. It should fix the problem. Also, check the oil level and quality. Always use the highest quality gas for the engine to receive the best engine performance and speed. 

For the clogged carb and air filter, you should solve them correctly. You may check the user manual for KFX 50 for quick troubleshooting. You can use WD-40 commercial cleaner to eliminate debris and residues from the carb, air, and oil filter. 

Plus, users have suggested replacing the stock air filter with the K&N one. You may even remove the washer from the cylinder to boost the speed.  

Malfunctioning Battery:

Rarely will you see the battery malfunctioning in Kawasaki KFX 50? The problem occurs mainly due to faulty wiring. Also, running the bike off-roads and over puddles might damage the wiring. The wire may come out loose. Also, the battery cells may lose their efficiency over time. If you run the quad in colder regions, its CCA level might drop dramatically. 

Fixing The Battery:

It would help if you started by observing the battery wiring. If you see any loose wire, reconnect it. Always secure the wiring and connection with electric tape. It boosts the longevity of the connection. Also, you should check the CCA level for the battery in cold conditions. 

You should recharge or replace the battery if the CCA level exceeds 50%. It will boost the battery performance Also, the riding will be smoother.  You may see the following YouTube video to learn the difference between CCA and cranking AMPs in Kawasaki bikes. 


These top three Kawasaki KFX 50 problems will considerably reduce riding safety and comfort. We hope the troubleshooting suggestions work to fix them quickly. Also, the United States Consumer Product Safety Commission (CPSC) reported that Kawasaki had recalled 15000 units of KFX 50 due to fire hazards. The recall took place due to leaks in the fuel tank. Since Kawasaki has recalled it, the problem doesn’t exist anymore. 

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