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How to Clean Goldwing Motorcycle Carburetors

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Cleaning the Carbs After Winter Storage

After a long winter's nap, I went to awaken the beast, my 1978 Honda Goldwing GL1000 with aftermarket Vetter fairing, sidebags, and boot.

I call it the beast because it is very heavy with a full tank of gas. Trying to maneuver it around the garage and in my inclined driveway is a herculean feat!

Last October, I meticulously prepared my bike for the long winter’s slumber by putting fresh gas in the tank, adding Stabil, and then running it with the fuel petcock off until the motorcycle died due to lack of fuel.

I was pretty certain that I had covered all bases to make sure the motorcycle’s carburetors would not get varnished up.

So after installing the battery and opening the fuel petcock, my Goldwing should fire up without an issue, right? Wrong, my Goldwing did eventually start but it was only running on three cylinders and it was dumping fuel into the intake manifold.

OK, so my next thoughts were to run it on several occasions until these problems worked themselves out. After the fifth session, I gave up on this premise and decided that the Carb Gods were not smiling down on me and I would need to rebuild the carburetors.

Don't Be Scared of Cleaning Your Carbs!

Cleaning Goldwing carbs is no harder than building a model airplane. If you have a good manual for your model, pay attention, and keep organized, the rebuild process will be a snap. I will walk you through the process.


Remove the Tool Kit Compartment

Open up the false gas tank; this is where you usually open to refuel. There is a little plastic tray containing a tool kit. It lifts straight up and out.


Remove the Air Cleaner Cover

You first need to remove the two fasteners that hold the false gas tank covers in place. These are the black knobby things to the left and the right. Then remove the wingnuts that hold the air cleaner top in place. See areas circled in the picture.


Remove the Air Filter

The air filter just sits in place; pull it straight up and out.


Remove Air Cleaner Housing Bolts

Remove the two bolts that hold the air cleaner housing in place. See areas circled in the picture. Don't try to pull it out just yet; there are two hoses attached to it.


Remove Hoses to Air Cleaner Housing

There are two hoses connected to the air cleaner housing; you need to remove these before it will come out. You will need to use needle nose pliers to release the hose clamps before the hoses will come off.

Once the hoses are disconnected, lift the air cleaner housing straight up and out. You may need to play with it a little before it comes out, as it is a very tight fit.


Protect the Intake Manifold

You can see the intake manifold now that the air cleaner housing has been removed. I place a clean rag in the intake manifold to make sure I didn't drop anything in there and to lessen the smell of gas from the carburetor fuel bowls. I did not drain the carburetor fuel bowls yet as it is difficult to get to the drain screws while still attached to the motorcycle.


Time to Remove the Bling!

I am not sure what these chrome pieces do other than hold the spark plug wires in place. At one time there was a plastic retainer in the center hole that kept the spark plug wires neat. You need to remove them on both sides. Four screws hold them in place.


Remove the Intake Runners

These chrome elbows have rubber pieces to dampen the vibration introduced to the carburetor assembly. You first need to remove the clamps at the top and then the bolts at the bottom. The runners come off rather easily if you rotate them 90 degrees and then pull them at an angle.


Remove the Fuel Line

Double-check to make sure the fuel petcock is set to off. Remove the fuel line from the fuel pump that feeds the carburetors. In this picture, it is the hose on the right. Immediately soak up any spilled fuel!


Remove the Carburetor Piston Set Covers

To slide the carburetor assembly out of the frame, you must remove all four piston set covers. One is installed on each carburetor. Two screws hold each cover in place.


Remove the Air Cutoff Valve

Also remove the air cutoff valve and the vacuum hose connected to it. Two screws hold it to the carburetor assembly. Make sure you don’t lose the o-rings that seal the air cutoff valve to the carburetor assembly!


Remove the Choke Cable

Remove the choke cable from the carburetor assembly. One screw holds the cable in place.


Remove the Throttle Cables

This is a little tricky; you almost have to be double-jointed to loosen the bolts and slide them from their mount. There are two throttle cables in a push-pull configuration. Both have to be removed.


Remove the Carburetor Assembly From the Motorcycle

It is time to remove the carburetor assembly from the motorcycle. The shop towel in the intake manifold also serves to soak up any fuel that may make its way from the float bowls into the intake. First, move the throttle and choke cables out of the way. You should be able to simply slide each carburetor assembly sideways out of the frame now with little resistance. It may take a little manipulation to get them out. When removing the carburetor assemblies from the motorcycle keep them level and in the same orientation that they were installed. Remember, the float bowls may still contain fuel.


Clean the Exposed Engine (Optional)

Here is a picture of the engine with the carburetor assembly removed. I recommend cleaning up this exposed area as you will not be able to access this area to clean once the carburetor assembly is re-installed.


Drain Fuel From the Float Bowls

Finally the carburetor assembly is free and clear of the motorcycle. I recommend draining the float bowls of any residual gas at this time. On each float bowl there is a screw head. Loosening this screw opens up a valve that allows the fuel to flow out. Make sure you soak up any fuel spillage before proceeding.


Remove the Rubber Hoses

Remove the rubber hoses between the intake manifold and the carburetors; there are four of them.


Separate the Halves of the Intake Manifold

In order to rebuild each of the carburetors, you must first separate them from the intake manifold. There are several long screws that hold the intake manifold together. These screws are very mild steel and our easy to round off the head. I recommend first grabbing the head of each screw with a vise grip to loosen it, then backing the screw out with a Philips screwdriver.

Below is a photo of the separated intake manifold.

Separated intake manifold

Separated intake manifold


Remove the Flame Arresters

Remove the flame arrester mesh. Four screws hold it in place, the same screws that attach the carburetor to the intake manifold. Each half of the intake manifold has a flame arrester mesh.


Remove Each Carburetor From the Intake Manifold

You should now be able to pull each carburetor from the manifold. Be careful not to lose the spring or the cross-shaped part that is part of the linkage that connects the choke and throttle butterflies together.

Below are pics of the individual carburetors separated from the intake manifold. Notice I removed the float bowl drain screws.

Keep parts organized!

Keep parts organized!

Disassembling and Cleaning the Carburetors

Now that you have the four individual carburetors removed from the intake manifold, you need to disassemble and clean each one. It is important that you not mix up the parts of one carburetor with another. I labeled four plastic bins (in the background) one through four and then with a Sharpie numbered each carburetor the same so as to keep the parts segregated.

Each carburetor is almost identical!

So I am only going to show you the tear down of one carburetor.


Remove the Float Bowl

Four screws hold it in place.


Remove the Float Assembly

The float is removed by driving the pin out.


Don't Lose the Float Needle!

Shown in the above picture.


Remove the Needle Float Seat

First unscrew the retaining clip, then remove the seat. It may require a little "persuasion" to come out.


Remove the Retaining Clip and Jets

The retaining clip holds the two jets in place.


Remove the Needle Jet Holder

Remove the needle jet holder (circled in the above picture).


Don't Lose the Needle Set Jet!

At the very end of the needle jet holder is the needle set jet. Do not lose it!


Remove the Main Nozzle

Unscrew the main nozzle; take care not to strip the head out as it is only made of soft bronze or copper.


Remove the Main Nozzle (Continued)

Here is another picture of the main nozzle.


Remove the Rubber Stopper

Remove the rubber stopper to expose the jet underneath.


Removing the Jet

Unscrew the jet inside; take care not to strip the head out as it is only made of soft bronze or copper. This jet has a number imprinted on the side, make a note of the number and where it was installed for assembly purposes.


Removing the Jet (Continued)

Another picture of the jet being removed.


Remove Cover

Remove the screw holding the cover and gasket; you will find two more jets under the cover.


Remove Two More Jets

Carefully unscrew each jet taking care not to strip the head. Each jet has a number imprinted on the side; make a note of the number and where it was installed for assembly purposes.


Remove Yet Another Jet

Carefully unscrew the jet taking care not to strip the head. This jet has a number imprinted on the side; make a note of the number and where it was installed for assembly purposes.


Remove the Fuel Mixture Screw Cap

Remove the plastic cap over the fuel mixture screw.


Remove the Fuel Mixture Screw

Finally, all four carburetors should be disassembled. Now it is time to clean all of the parts.

First I purchase four 16-ounce cans of automotive carburetor cleaner from my local auto parts store. I then set up a table outside to perform the cleaning process. The carburetor cleaner fumes can be noxious so it is important to work in a well-ventilated area.

I then bring the carburetors out, each in their respective container, and start up the old air compressor. I use the air compressor to thoroughly dry each part after it has been sprayed with carburetor cleaner.

Finally I use aerosol can tops as small soaking tanks for the discrete parts removed from the carburetors.

Cleaning the Disassembled Carburetors

Before removing the fuel mixture screw, document the orientation of the screw head, then tighten it clockwise, while counting the number of turns, until the screw reaches bottom. Document the number of turns. During reassembly this screw needs to be the same number of turns from the bottom and the screw head orientation needs to be set the same way. This ensures that the fuel mixture is set correctly. Loosen the fuel mixture screw for removal by turning it counter-clockwise.

Safety First!

First things first, wear eye protection so that you do not accidentally get carburetor cleaner splashed in your eyes and keep your mouth closed as it is probably not a good idea to swallow it. I also wear heavy-duty chemical-resistant gloves as the carburetor cleaner does a wonderful job of drying out your skin and nail cuticles.

Let the Cleaning Begin!

I connect the small tube that comes with the carburetor cleaner to the nozzle, then systematically spray into each orifice where the jets and idle mixture screw were removed. Each of these passages needs to be clean of debris, varnish, and carbon.

You will know when a passage is clear because you will see carburetor cleaner come out of the other end. If you look down the throat of the carburetor, you will see small pin-size holes next to the throttle butterfly valves. These holes need to be clear and free from debris if you want your motorcycle to perform properly!

Clean, Then Repeat

I give each carburetor body several thorough cleanings with spray carburetor cleaner, then dry them off with the air compressor shooting air into each orifice, inspect, then repeat the process.

Don't waste the carburetor cleaner by spraying down the whole carburetor body or the intake manifold; focus on the internal passages that actually are involved in the fuel/air mixture process.

Cleaning the Small Discrete Parts

Remember; keep the discrete parts, all of the little parts that you took off of the carburetor body, from each carburetor segregated. For best performance, you want to install the parts on the same carburetor body you removed them from.

For cleaning the discrete parts, I turn aerosol can tops upside down, place all of the parts in the tops, then spray carburetor cleaner in the tops and use them as mini soaking tanks. I let the parts soak for about fifteen minutes, then use needle nose pliers to extract each part from my mini soak tank. I let them air dry on a clear shop rag.

The floats are too big to fit in the aerosol can top, so I just spray them down with carburetor cleaner.

Inspect the Discrete Parts

Each jet has a tiny precision hole drilled down the center to properly meter the right amount of fuel. It is important that these holes be clear and free of debris, carbon, or varnish. If the hole is blocked, try to open it up by spraying some carburetor cleaner through the hole. Do not try to remove the blockage by mechanical means, like using a wire; this can alter the performance of the jet. Some jets are tiny cylinders with a number of holes drilled on the side; make sure these are clean as well.

Re-Assembling Your Carburetors

The assembly process is the opposite of the disassembly process. Just read from the bottom of this article to the top and you will have those carburetors attached to the intake manifold and back in the bike in no time. Remember that you need to re-install the discrete parts in the same carburetor you removed them from. Also remember that each jet has a number imprinted on its side, and you need to install the jet in the same place on the carburetor you removed it from.

Rebuilding Goldwing carbs is no harder than building a model airplane. It you have a good manual for your model, pay attention, and keep organized, the rebuild process will be a snap.

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.

© 2013 jbdkz