5 Typical Problems with Kawasaki KLX250

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The Kawasaki KLX250 is the perfect dirt bike for off-road travel. But its performance goes further than just that. This bike was built for both on-road and off-road riding. This model brings unparalleled versatility, amazing power, and high and consistent performance. The 249cc DOHC fuel-injected four-stroke engine and the strong torque ensure an easy start and a smooth ride even on rugged terrain.

Photo by Yuya Murano CC BY-NC-ND 2.0

The adjustable front and rear suspensions on this lightweight bike make it a great fit for a wide range of riders. Whatever your goals, this bike won’t fail to deliver. However, all things being said, there are still some potential issues you might run into. These aren’t caused by the model itself and are common in most dirt bikes. Let’s take a look at 5 of the most frequent issues you might encounter with a KLX250.

1. Bike Won’t Start

This is a common problem with the KLX250 and most other dirt bike models, for that matter. Sometimes, no matter what you do, it seems like the bike is dead-set on not starting. Now, there are multiple possible reasons and solutions to this issue. You’ll have to take a thorough look at your bike to find the exact cause.

The most common reasons are a dirty carburetor or bad gas. A dirty carburetor problem is quite easy to fix. Sometimes, something as simple as draining the carb will solve this issue. If you do this and the problem persists, it’s time for a thorough cleaning.

As for bad gas, switching fuels might help. Many people believe that the fuel grade you choose doesn’t make a difference. But this couldn’t be further from the truth. The user manual comes with specific instructions about the suitable fuel grade, after all.

For the KLX250, you should be using octane fuel rated 87 or higher. Other possible but less common causes might include a weak or dead battery (for the electric start), and compression or jetting problems.

2. Clutch Problems

You need the clutch to shift gears. You also need it when you want to stop your dirt bike without stalling when it’s not in gear. This is a very important mechanism and you can’t do without it. However, sometimes the clutch can become defective and this can also affect the functionality of the engine.

The clutch uses friction plates. The clutch springs create compression, which makes the plates grip. When the pressure is released, the friction plates slip. Both of these movements are essential for the well-functioning of the clutch mechanism. But as you may already know, whenever there are moving parts, you’re going to eventually run into some issues.

The most common problems on the KLX250 are either a dragging clutch or a slipping clutch (when it’s not supposed to). Both of these issues can be easily solved by adjusting the clutch cable. Make sure everything is properly in place.

Sometimes, a slipping clutch can also be caused by worn-out clutch plates, in which case you’ll have to look into replacing them. Additional causes of a dragging clutch include warped plates and sticking or gunked-up plates due to old fuel build-up.

3. Bike Won’t Idle

Sometimes, you want to bring your bike to a standstill without killing the engine. But when you have an idling problem, you might find that your motor suddenly stops. There are a few possible causes for this:

  • Your idle screw might need some readjustment. Remember, the idle screw’s job is to control how much fuel reaches the engine when you aren’t touching the throttle.

If the idle screw is set too low, the engine might not receive enough fuel to keep running when idle. This is also one of the main problems when cold-starting a bike. But this is an easy fix. All you have to do is locate the screw and rotate it to bring up the idle RPM.

  • A dirty air filter can also affect the engine. The bike engine uses both fuel and air for combustion. But a dirty air filter makes it harder for the air to get where it’s supposed to. In this case, you might get a rich air to fuel mixture.

Your bike might start smoking up and you’ll end up with lower idle power. Regularly cleaning or replacing the air filter will get rid of this issue.

  • Similarly, the fuel screw can also cause fuel issues. The screw can be the cause of a too rich or too lean mixture. When the air to fuel mixture is too rich (too much fuel and too little air), the idle drops.

When the mixture is too lean (more air than needed mixing with the fuel), the idle will rise, but the engine might start knocking.

Simply locate the fuel screw and adjust it little by little until you find the perfect middle ground where you get a high idle with a good throttle response.

4. Fouled Spark Plugs

Spark plugs are a very important part of the ignition system. As the name suggests, spark plugs create a spark, which you need to ignite the air-fuel mixture in the engine. Without them, the engine won’t start. This is a less common issue on 4-stroke models like the KLX250, but it isn’t unheard of.

In most cases, the cause of fouled spark plugs is rich jetting. When the engine receives more fuel than it can burn, the rest of the fluid might seep through and onto the spark plugs. When the plugs get wet or dirty, they stop doing their job properly. A clear indication of rich jetting is excessive smoking. If you notice black smoke coming out of the exhaust pipe, that’s your sign.

A dirty air filter can also foul up the spark plugs. When not enough air reaches the engine, the excess unburned fuel creates a residue that can foul the spark plugs, limiting their ability to deliver the spark to fire up the engine.

5. Gas Leaks

Gas leaks are a problem for multiple reasons. They lead to fuel waste and the leaking fuel can gunk up the engine and other components. But most importantly, it’s dangerous to have a highly flammable liquid dribbling out of the tank and somewhere where it shouldn’t be.

The most common problem areas for gas leaks are usually the fuel bowl, the fuel switch, the carb drain screw, or the carb overflow. The most probable cause for this is a cracked o-ring or gasket.

Wherever you have a seal, you might experience such issues. If the seal isn’t properly in place, or if there’s a crack, fuel can seep through. A high float level can also lead to gas spilling out of the overflow tube.


These are some of the most common problems you might run into with your Kawasaki KLX250. Note that these aren’t guaranteed. How you maintain your dirt bike will play a major role in preventing some of these issues.

Overall, this model is very capable, versatile, and most of all, reliable. This dirt bike is durable and perfect for all skill levels. If you’re looking for good performance and a lightweight vehicle for both on- and off-road riding, the KLX250 makes a great choice. These are just some potential issues you should keep in mind.

Josh Berry - MotoShark Editor
Josh Berry
I'm a off-road enthusiast, extreme sport fan and the editor of MotoShark. If you have any questions or suggestions regarding this article, please leave a comment or contact me.

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