KTM Motorcycle Carburetor Problems (9 Must-Know Facts!)

The humble carburetor is still one of the most crucial components on a motorcycle. It is responsible for managing the proper airflow and mixing of air and fuel that the engine depends on to provide throttle and power.

It is therefore a component that the motorcycle still can’t do without.

This article explains 9 must-know facts about “KTM motorcycle carburetor problems!”…

How Does A Carburetor Work?

A carburetor works using the Venturi Effect. Air passes through tubes in the carburetor, which narrows in key points to create the drop in air pressure that the Venturi Effect predicts. The drop in pressure draws fuel into the mixture, which is then passed to the engine.

That air/fuel mix is what drives the combustion that powers any non-electric motorcycle.

The Symptoms Of A KTM Failing Carburetor:

A carburetor on a KTM motorcycle, as with other brands, can fail for a number of reasons.

Below are some of the most common:

  • Lost power during acceleration
  • Difficulty cold starting
  • Sputtering
  • Hissing sounds from the carburetor

The KTM bikes are popular as both on- and off-road bikes, and are designed by engineers who live and work in the high altitude of the Austrian Alps.

The bikes have been known to have some issues when used more as regular bikes rather than the hardier applications the creators imagine.

They are certainly good road bikes, but if you experience a loss in acceleration or power, or your exhaust starts sputtering, for example, what it likely means is that the jets have become clogged.

The buildup within the KTM carburetor can sometimes lead to difficulty starting, especially cold starting because the carburetor isn’t bringing in enough airflow to draw out the fuel needed for a successful ignition.

One more symptom to listen for is a hissing noise, which can indicate gas leaks coming from the carburetor.

These leaks are caused by worn gaskets, and this has been known to happen on KTM bikes.

Are KTM Carburetors More Prone To Fail Than Other Motorcycles?

KTM bikes are known for suffering from more easily clogged pilot jets, but that’s not to say that they are objectively easily clogged, just somewhat more easily than brands like Suzuki and Honda.

Overall, KTM carburetors are reliable and well-constructed with very durable parts and materials.

They do still fall somewhat short of their Japanese competition, in particular Suzuki and Honda, both of whom enjoy somewhat lower overall failure rates than KTM.

How Long Should A KTM Carburetor Last?

If you properly clean and manage the buildup that comes into the pilot jets and other areas of the carburetor, then there’s nothing to stop your KTM carburetor from lasting the entire lifespan of your motorcycle.

KTM bikes can easily last 75,000 miles, and if properly maintained will stretch well over into the zone of 100,000+ miles.

The carburetor is central to that overall health since it regulates the critical mixture of air and fuel that keeps the engine ticking over properly.

The key to making a KTM carburetor last is to keep track of the pilot jets, using compressed air and WD40 to keep them as clean and clear as possible.

One more thing to monitor is the gaskets, which can be the center of gas leaks when they become too worn.

What KTM Models Are Likely To Have Carburetor Problems?

Among the many bikes in the KTM range, two models stand out as somewhat more susceptible to carburetor problems, namely the KTM 50 and KTM 520.

KTM 50 owners have reported issues with idling, specifically that the KTM 50 will start up ok, but then won’t idle, instead of stalling or sputtering out.

It’s a frustrating issue and one that requires the carburetor to be removed and closely inspected.

The problem typically lies with the idle screw.

A more frustrating thing on the KTM 50 can be that when the idling problem is solved, there is a problem with surging when you open the throttle.

This is an issue of blocked jets. It can cause a build-up of pressure that can suddenly find release as the buildup shifts.

This makes it easy to flood the engine and stall out, especially after a cold start.

The KTM 520 has some issues with the fuel screw. The metal surrounding the screw is quite soft, and some owners have caused damage by cranking it in too tightly.

Any kind of physical damage to the main housing and surrounding of the carburetor is a problem because while individual components and moving parts can be purchased and replaced, the structure is much harder, sometimes impossible, or pointless to repair.

This kind of damage can leave you with no choice but to replace the carburetor, which is more expensive.

What Are The Possible Causes Of A KTM Failing Carburetor?

The most common cause of an apparently failing carburetor on a KTM motorcycle is a blocked pilot jet.

Probably about 6-7 times out of 10, problems in the KTM carburetors are linked to this jet.

Another common issue is found in damage caused to the carburetor housing by owners cranking the fuel screw in too tightly.

Worn gaskets on top of the KTM carburetor bowl are another source of issues, specifically gas leaks.

If gas is escaping – you’ll hear a hissing sound if it is – then it’s directly affecting the air/fuel mixture being generated within the carburetor and will therefore negatively impact engine performance and acceleration.

With engine sputtering being common among that segment of the KTM owners who are experiencing problems, the cause of that is down to the air/fuel mixture running lean.

This can be traced once again back to blockages and buildups within the carburetor.

What Are The Possible Solutions Of A KTM Failing Carburetor?

The first and primary solution that any owner should take is a proper cleaning and possible replacement of the pilot jet.

Some owners say that cleaning the pilot jet with compressed air and/or WD40 is enough because it removes the buildup and allows proper airflow to return.

Others point out that the more fundamental problem is the stock OEM pilot jet is not big enough to match the power of many KTM models.

Replacing it will reduce the possibility of future buildups and thus reduce the burden on the owner having to constantly clean it.

Other solutions include replacing the gaskets on top of the carburetor bowl.

This is a fairly simple and cheap process but can be a little time-consuming because it’s fiddly and precise.

The solution to the fuel screw problem is simple for owners to crank it more gently and/or with a more appropriately sized tool or the delicacy of the screw and surrounding material.

The “sledgehammer” approach is not a good idea.

Can A KTM Motorcycle Run With A Failing Carburetor?

Technically, your KTM bike will run on a failing carburetor, but it’s impossible to say for how long.

A failing carburetor presumably is still bringing in some airflow and fuel, and so is performing its task, just to a lower degree of success.

A failing (but still technically operating) carburetor will come with reduced engine power and quite possibly massively reduced gas mileage.

You might actually run out of fuel as the last of it is spewed out in the black smoke coming from your exhaust.

When you see the symptoms of a failing carburetor on your KTM bike, your first port of call should be the dealership where you bought the KTM bike.

The carburetor likely can be repaired without the need for it to be replaced.

If it fails completely, however, your KTM bike will just stop working altogether and then you’ll have to push it to the auto shop or get it collected.

Does Cleaning The KTM Carburetor Prevent Failing?

Like just about every motorcycle brand on the market, cleaning the KTM carburetor can absolutely extend its life and keep it working normally throughout your entire ownership period of that motorcycle.

It’s not the only thing you’ll have to do, but it’s a great start.

Can I Clean It Myself?

Yes, cleaning the KTM carburetor yourself is perfectly possible, and easier than you think so long as you can remove it before cleaning and reinstall it after finishing the job.

Using simple tools and a little know-how, you can do a lot to restore the carburetor back to near-new condition through cleaning alone.

Can I Use WD40 To Clean It?

Yes, WD40 is a very effective cleaning tool for your KTM carburetor because of its precision nozzle that can reach various jets and shafts.

It’s even better when used in conjunction with compressed air and a proper cleaning kit that you can purchase from your local auto supplies store.

Can I Clean It Without Removing It?

Yes, you can, but it is generally seen as trickier overall to clean it while it is still attached to your bike.

The main issue isn’t getting it cleaner, but rather the precision and depth of the clean are hard to emulate compared to removing it first.

If you have space and the ability to position the bike conveniently to access the carburetor housing, remove the covering parts and clean it while it’s still attached to the bike, then that’s fine.

It’ll be harder, though.