Your carburetor keeps your motorcycle or ATV running at its peak efficiency. If it gets significantly dirty, it will seriously affect your machine’s performance – to the point where it may stop working properly altogether. What do you do when you find yourself in this predicament? Clean it.

Picture of a Rider Cornering on a Suzuki Dirt Bike

A carburetor is a complicated component of your machine, so you might feel intimidated removing it and giving it a proper cleaning. Don’t be! As long as you go through the process step by step, there’s no reason why you can’t clean your carburetor yourself.

Take a look at this video to see how it’s done. Or if you’d rather read it, written instructions are provided below. This tutorial was performed on a Kehin FCR carburetor from a 2007 WR250F, but it will be similar for other powersport carburetors (especially modern performance 4-strokes).

Before You Begin

Before you start taking the carburetor off and disassembling it, there are a few things you should gather together before you begin. Additionally, since many pieces of the carburetor are fairly delicate, there are a few precautions you should be aware of beforehand.

Necessary Equipment

Gather up the following items before you get started. You can do without some of them, but it’s best if you purchase whatever you’re missing.

Items Needed to Begin
Picture of Several Different Service Manuals Picture of a Clean Rag Picture of PJ1 Pro-Enviro Carb and Choke Cleaner
Service Manual Plenty of Rags Carburetor Cleaner
Picture of a Tusk Hex Key Wrench Set Picture of a Tusk 6 in 1 Screwdriver Picture of a Small Screwdriver
Hex Key / Allen Wrench Screwdriver Small Screwdriver
Picture of a Tusk Deep Socket T-Handle Wrench Picture of an Open-End Wrench Picture of a Compressed Air Hose
Socket Wrench Wrench Compressed Air
Picture of ThreeBond Low Strength Thread Locker Picture of some Latex Gloves
Low/Medium Strength Thread Locker Gloves

The most important of these items is the service manual. There are many types of bikes and quads, and that means that every carburetor is different. While this tutorial will be similar for your machine, it will not be exactly the same. Your service manual will guide you in the differences. Additionally, your service manual will describe the sizes of the tools that you need.

It’s also important to note that while compressed air is helpful, you may not have access to industrial compressed air as demonstrated in this tutorial. If you don’t, that is fine. You can often find pressurized air in cans at retail locations.

While gloves are not required, it’s not a bad idea to use them. It’s best to avoid getting carburetor cleaner on your skin.

Things You Should Know

The carburetor demonstrated in this tutorial is from a 2007 WR250F. Your carburetor will probably look slightly different.

A significant part of cleaning a carburetor is disassembly and reassembly. Many of the screws and bolts are delicate. Use the appropriate screwdriver so that you don’t strip them out. It’s also important not to overtighten them.

Most components need to be wiped with a rag after you spray them with carburetor cleaner (even if it is not explicitly mentioned in the instructions below). It’s also ideal to spray some components with pressurized air, even after you have wiped them with a rag.

Also, there are some components that you should not clean with carburetor cleaner:

  • The O-ring on the front slide plate
  • The diaphragm in the accelerator pump assembly
  • The diaphragm in the air cut-off valve (if your carburetor has one)

Spraying these items with carb cleaner can damage them. When you remove each of these, make sure that you place them in an area where you won’t inadvertently spray them.

The first thing you need to do is actually disassemble your carburetor so that you can clean each individual component. You can either clean each piece as you remove it, or you can set them all aside to clean after everything is disassembled. These instructions discuss cleaning in the next section rather than as part of the disassembly.

Remove the carburetor from your machine.

  1. Refer to your service manual if you are unsure how to do this.

Clean the outside of the carburetor.

  1. Before you open it up and remove anything, spray off your carburetor with carb cleaner. Why? If there is any dirt on the outside, it’s important to remove it at this point.
  2. Picture of Spraying the Carburetor with Cleaner

  3. Don’t forget to wipe it with a rag before proceeding.
  4. Picture of Wiping the Carburetor’s Outside

Remove the slide valve.

  1. Start from the top by removing the valve lever housing cover. You should be able to do this by unscrewing a couple of bolts.
  2. Remove the throttle shaft screw that is directly underneath the valve lever housing cover.
  3. Picture of Removing the Throttle Shaft Screw

  4. Rotate the control arm. This lifts the slide up.
  5. Picture of Rotating the Control Arm

  6. Now that it is in position, remove the slide assembly from the carburetor.
  7. Picture of Removing the Slide

  8. Watch for the front slider plate. Sometimes it stays in the carburetor. If it does, gently turn the carb upside-down, and the front slider plate should fall out. The O-ring on the front slider plate should not be cleaned with carburetor cleaner.

Remove the accelerator pump assembly components.

  1. Remove the fuel screw. You may need a flat-blade screwdriver to remove it.
  2. Picture of Removing the Fuel Screw

  3. Remove the three screws that hold the accelerator pump cover on.
  4. Picture of Removing the Accelerator Pump Cover Screws

  5. Pull the accelerator pump cover off.
  6. Underneath the pump cover is a spring. Remove it.
  7. Gently pull the accelerator pump diaphragm out. Pay attention to its direction so that you’ll be able to reinstall it later. This diaphragm should not be cleaned with carburetor cleaner.
  8. Picture of Removing the Accelerator Pump Diaphragm

Remove the float assembly.

  1. Loose and remove the float bowl plug. You’ll probably need to use a wrench to get started, but after that you can use your fingers. Note that the pilot jet and the main jet are accessed in this opening.
  2. Picture of Removing the Float Bowl Plug

  3. Remove the four float bowl screws.
  4. Picture of Removing the Float Bowl Screws

  5. At this point, you can actually pull the float bowl off.
  6. Picture of Observing the Removed Float Bowl

  7. Push the float pin out.
  8. Picture of Pushing the Float Pin Out

  9. Remove the float assembly.
  10. Picture of Removing the Float Assembly

  11. Remove the float needle from the float.
  12. Picture of Removing the Float Needle

Remove the jets.

  1. Remove the main jet. You may need to use a socket wrench to do this. On the 2007 WR250F, it’s a 6 mm socket wrench.
  2. Picture of Removing the Main Jet

  3. When you pull the main jet out, the needle jet may be attached. These need to be separated, though you can do so later if you prefer.
  4. Picture of Observing the Needle Jet Attached to the Main Jet

  5. Pull out the plastic spacer.
  6. Picture of Removing the Plastic Spacer

  7. Remove the pilot jet.
  8. Picture of Removing the Pilot Jet

  9. Remove the starter jet.
  10. Picture of Removing the Starter Jet

Remove the air cut-off valve components.

  1. This step only applies if your carburetor has an air cut-off valve.
  2. Unscrew the screws on the valve cover.
  3. Picture of Unscrewing the Valve Cover Screws

  4. Remove the cover.
  5. Underneath the cover is a spring. Remove it.
  6. Remove the air cut valve diaphragm. This diaphragm should not be cleaned with carburetor cleaner.
  7. Picture of Removing the Air Cut-off Valve Diaphragm

Now it’s time to clean each component of the carburetor. The carb cleaner comes with a small red hose. Make sure that you use this so that you can be as precise as possible.

Spray in every nook and cranny to make sure that you get all the dirt and sand out. Ensure that whenever you spray into a hole, the cleaner comes out somewhere else. If it doesn’t, it could mean that something is blocking that circuit.

Clean the carburetor body.

Here are just a few things to remember to clean on the body of the carburetor.

Cleaning the Carburetor Body
Picture of Cleaning the Air Cut-off Valve Circuit Picture of Cleaning the Air Jets
Air Cut Valve Circuit Air Jets on the Back of the Carburetor
Picture of Cleaning the Fuel Inlet Picture of Cleaning the Three Jet Holes
Fuel Inlet All Three Jet Holes (Starter Jet, Main Jet, Pilot Jet)
Picture of Cleaning the Fuel Line Picture of Cleaning the Slide
Fuel Line Coming from the Accelerator Pump Slide
Picture of Cleaning the Hot Start Circuit Picture of Cleaning Every Hole on the Body of the Carburetor
Hot Start Circuit Every Hole

Clean the choke assembly.

  1. Remove the choke plunger assembly with a wrench.
  2. Picture of Removing the Choke Plug Assembly

  3. Clean the plunger off when it is removed.
  4. Spray the circuit out with carburetor cleaner.
  5. Picture of Spraying Out the Choke Circuit

  6. Reinstall the choke assembly.

Clean the slide assembly.

  1. Remove the wheels from the slide. (Your carburetor may be a little different.)
  2. Picture of Removing the Slide Wheels

  3. Spray the slide off and wipe it.
  4. Spray the individual wheels and wipe them as well.
  5. Reassemble the slide, putting the wheels back on.
  6. Picture of Replacing the Slide Wheels

Clean the float bowl.

  1. Spray the float bowl with carburetor cleaner.
  2. Picture of Spraying the Float Bowl

  3. Wipe the float bowl really well.
  4. Remove the leak jet. You will need a small screwdriver. (Be careful not to strip it.)
  5. Picture of Removing the Leak Jet

  6. Spray all the channels to or from the accelerator pump to make sure that they are free of dirt or sand.
  7. Picture of Spraying the Channels of the Float Bowl

Clean the covers.

If you haven’t already done so, there are several covers that need to be cleaned.

Cleaning the Covers
Picture of Cleaning the Valve Lever Housing Cover Picture of Cleaning the Accelerator Pump Cover Picture of Cleaning the Air Cut Valve Cover
Valve Lever Housing Cover Accelerator Pump Cover Air Cut Valve Cover

Spray off all parts with compressed air.

  1. Spray off the covers you’ve cleaned with compressed air.
  2. Picture of Spraying the Accelerator Pump Cover with Compressed Air

  3. Spray compressed air through each jet. If you haven’t already done so, you’ll need to separate the needle jet from the main jet before you blow them out.
  4. Picture of Spraying the Pilot Jet with Compressed Air

Now that everything is cleaned, it’s time to put it all back together.

Reinstall the jets.

  1. The first thing to do is reinstall all of the jets. Tighten each one as far as it will go. There isn’t a particular setting for how many turns are required, but be careful not to overtighten them.
  2. Reinstall the leak jet.
  3. Picture of Reinstalling the Leak Jet

  4. Reinstall the starter jet.
  5. Picture of Reinstalling the Starter Jet

  6. Reinstall the pilot jet.
  7. Picture of Reinstalling the Pilot Jet

  8. Reinstall the plastic spacer.
  9. Picture of Reinstalling the Plastic Spacer

  10. Reinstall the needle jet.
  11. Picture of Reinstalling the Needle Jet

  12. Reinstall the main jet. It threads right into the needle jet. You’ll need to use a socket to tighten it, but be careful not to overtighten as it can break off.
  13. Picture of Reinstalling the Main Jet

Reassemble the float bowl.

  1. Reinstall the float needle.
  2. Picture of Reinstalling the Float Needle

  3. Sit the float down into the carburetor. Make sure that the float needle sits in the supply hole.
  4. Picture of Replacing the Float

  5. Slide the float pin into place.
  6. Picture of Replacing the Float Pin

  7. Attach the float bowl back to the carburetor. Make sure that everything lines up and goes together smoothly.
  8. Picture of Attaching the Float Bowl to the Carburetor

  9. Replace and tighten the float bowl screws. Be careful not to overtighten them. If you crank too hard, you’ll almost certainly strip them out either now or when you next take them out.

Reinstall the accelerator pump assembly components.

  1. Reinstall the accelerator pump diaphragm. Make sure the small button is facing up or out.
  2. Picture of Reinstalling the Accelerator Pump Diaphragm

  3. Hold the spring in place while you set the accelerator pump cover on top.
  4. Picture of Holding the Spring While Retrieving the Accelerator Pump Cover

  5. Install all three screws onto the accelerator pump cover and tighten each one.
  6. Replace the float bowl plug and tighten it.
  7. Picture of Tightening the Float Bowl Plug

Reinstall the air cut-off valve components.

  1. Remember that not all carburetors have an air cut-off valve, so you might need to skip this step.
  2. Replace the O-ring.
  3. Picture of Replacing the Air Cut-off Valve O-ring

  4. Position the diaphragm into place.
  5. Picture of Positioning the Air Cut-off Valve Diaphragm

  6. Replace the air cut-off valve spring and cover.
  7. Picture of Replacing the Air Cut-off Valve Spring and Cover

  8. Install the bracket to hold the breather hose in place (if applicable).
  9. Reinstall and tighten the screws on the air cut-off valve cover.

Reinstall the slider assembly.

  1. Make sure that the O-ring is installed on the front slider plate.
  2. Replace the front slider plate on the slider.
  3. Picture of Replacing the Front Slider Plate

  4. Place the slide assembly back in the carburetor. The rollers will fit in the slits as you slide it down into the carburetor.
  5. Picture of Placing the Slide Assembly Back in the Carburetor

  6. Apply medium strength thread locker to the threads of the throttle shaft screw.
  7. Picture of Applying Thread Locker to the Throttle Shaft Screw

  8. Install the screw in the throttle shaft assembly and tighten it.
  9. Picture of Installing the Throttle Shaft Assembly Screw

Reinstall the remaining carburetor components.

  1. Replace the valve lever housing cover, making sure the O-ring is in place.
  2. Picture of Replacing the Valve Lever Housing Cover

  3. Reinstall the bolts and tighten them down.
  4. Replace the fuel screw.
  5. Picture of Replacing the Fuel Screw

  6. Once you have installed it, thread it back out to its original setting. (If you use the Tusk fuel mixture screw, this is easy because you can more accurately count the number of turns.)

Reinstall the carburetor back into your motorcycle or ATV.

  1. Refer to your service manual if you do not know how to do this.

Congratulations

At this point, you’ve successfully cleaned your carburetor and put it back together. You’re ready to go!

If you discovered that your carburetor needs replacement parts, take a look at our fuel and air intake or carburetor jet sections at the primary Rocky Mountain ATV/MC site. We also carry an extensive amount of OEM carburetor parts from major motorcycle and ATV manufacturers.

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Did you notice a significant difference in your machine’s performance after cleaning your carburetor? Share your success story with us in the comments.

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