Carburetor cleaning / rebuild

[Frank Angerano]

 

I’ve decided to post  a thread on the process of cleaning a carburetor and what’s needed in order to do it properly. 

 

There are some members that are new to this and are not very versed in doing so. I want to help and feel this might explain things better. I would hope this helps you along.  

 

We all have our own little tricks of the trade so I’m sharing my process on how i break a carburetor down, clean, reassemble and adjust it to peak performance. I welcome any other members input on this topic.  

 

List of things I use:

 

Safety glasses !!!

 

Rags.

 

I like to use old white Tee shirts or I buy and always have a few white pillow cases from the dollar store on hand. The cheap ones.  

 

I like to use a frisbee turned      upside down like a bowl to keep the liquids to a minimum on spillage to the work bench. 

 

A set of cleaning picks and brushes or a piece of bicycle break cable, I separate the strands and use them to clean out the tiny holes in the jets.

(Pic attached)

 

 

A can of gum out  carburetor cleaner with the small red tube that attaches to the spray tip. 

(Pic attached)

 

A can of compressed air, the kind used to clean out keyboards on computers. It also has the small red tube that attaches to the spray tip.  Or a compressor if you have one with a blow out tip. 

(Pic attached)

 

A piece of clean hose that I can connect to the fuel line port on the carburetor to test the float operation. About 10 inches long. 

 

A few Q tips.

 

The process:

I like to put the pillow case down on the work bench and spread it out flat.   This really helps in being able to keep track of parts. Especially because it’s white. 

 

 I use the frisbee because it’s small enough to keep parts contained and durable enough to deal with the chemicals and any gas that will come out of the carburetor while opening it up.  

 

It’s important to make sure you keep track of where everything came off and where the screws and parts all go back.  

 

I like to start at the bottom and pull the bowl off. I immediately spray the inside of the bowl down with carb cleaner until its about half way full and set it aside.  

Then I take the float out and check it for any fluid inside. If it’s a white color float you can hold a flashlight under it and see through it for any fluid inside.  If it black just shake it up and listen for fluid inside. No fluid inside is a good thing ! 

 

When the float comes out the fill valve needle will come with it. I take that needle and put it in the carburetor bowl that I filled with carburetor cleaner. This way it soaks for a bit. I do the same thing with the jets also once they are unscrewed and out toss them into the bowl to soak.   

Take the air/fuel mixture screw out and soak that as well. 

Side note: the air/fuel screw should have a screw, spring, washer and o ring. 

 

After all the jets and parts are out and soaking I like to take the carburetor cleaner, use the small red tube and stick it in all the little holes/ports on the carburetor and spray.   I do this while it’s in the frisbee. This way there is no mess. I look to see where the spray pressure comes out on the other side of that port.  

Once this is all done I start running my brushes and cleaning tips gently through all of the holes/ports and spraying it again with the carb cleaner. 

After I feel I’ve seen a clear flow of fluid through all the openings I spray them with the can of air the exact way I did with the carburetor cleaner. This will blow out any left over junk that’s still in the carburetor.  

Check the choke operation is working properly and spray it clean. Most choke devices are easily cleaned up so hit it and move on since they are mechanical and it’s just a matter of freeing them up, spraying with cleaner and lube.   There are multiple types of chokes but many of them for the most part are mechanically operated. 

 

Once this is completed I wipe the entire carburetor down good and blow it clean and set aside.  

 

I then start working on the jets one by one. Start by running the cleaning tips and brushes through all the tiny holes making sure they are all clean. Hit it with the carburetor cleaner and then air. I hold a flashlight to it when it’s done so I can make sure all of the holes are clear. I set all the jets aside on the work area.  Do the same thing for the float needle and air/fuel screw. 

 

Now once this is all complete you can set the frisbee aside and start to reassemble the carburetor on the clean white surface.  

I start by running a Q tip in where the fill needle sits into the carburetor. Some carbs have a small o ring that needs to be clean for proper seating of the fill needle.  

 

Carefully reinstall the jets where they came from and do not strip or over tighten the jets and use the proper size screwdrivers when removing and reinstalling the jets. 

 

Reinstall the air/fuel mixture screw and set it to what’s called out in the manual for that bike. 

 

Install the float and fill needle assembly. 

 

Now in order to test that float I like to take that piece of hose I mentioned and connect it to where the fuel line gets connected to the carburetor. I then turn the carburetor over to the upright position and blow into the hose. You should hear air coming out of the bottom of the carburetor. While blowing, lift the float up and the air should stop.  Let it go and the float should fall down opening the fill valve and you should hear air again. 

The air should stop about 3/4 way up when raising that float while your blowing air into it.   If so then your good to go. If not make an adjustment 

 

Set the carburetor down, take the bowl and empty it.   Clean it out and scrape/wipe any old junk inside and blow it out good.   There is a screw on the outside of the bottom of the bowl. Remove it and clean it out and reinstall.  

 

Turn the carburetor over and reinstall the bowl. Tighten the screws in a crisscross pattern so the bowl seats evenly.  

 

I like to put the hose on one more time and do a float test to make sure it’s opening and closing properly. All you have to do is blow into the hose and run the carburetor  upside down to see if the air stops.  

 

Reinstall the carb and you should be good to go! 

 

All pics of the items I use are attached below.  

If you understand this great. If not ask away! Don’t be shy and don’t cut corners.  

You will only wind up pulling the carburetor off of the bike for the third and forth time before you get it right. 

 

The last thing to be discussed is dialing in the air/fuel screw when your finally put back together and running.  This is a relatively easy task.  

Again I hope this helps! 

 

Frank.   

 

[06kfx440]

Great write up frank!


Sent from my iPhone using Tapatalk

[mikeexplorer]

X2 great write up!

 

[Romain Catinaud]

Thank you for that!

[Russell Senior]

Great write up.  I'd like to add that this tool is my friend.  Get's all the passages you can't get to. 

https://www.harborfreight.com/25-liter-ultrasonic-cleaner-63256.html?_br_psugg_q=ultrasonic+cleaner

 

[Frank Angerano]

I may just pull the trigger and buy one of these one day.  But I’ve always been successful doing it the way I have been for years.  

I would not mind having one though for carburetors and a lot of other parts.

I could definitely see breaking a carburetor down and putting all the parts and the carburetor in the cleaner for a while making my job a little easier  

I rebuilt the carburetor for my Mojave today and it came out great just need to dial it in I’m  sure after the bike is finished.  But cleaning all the little spots on the carburetors is a pain in the as*.  I’m not talking  about the little spots that matter or make it run but when I do a carburetor I like to make it look like new inside and out! 

So we will see, I will give it a shot.  

 

[MarkinAR]

I'd add that based on personal experience, the O'Reilly brand carb cleaner seems to be about the strongest on the market i've seen.  Not sure who makes their store brand but it's wicked strong.  It'll peel paint.  It's real close to carb cleaner from 20 years ago.

BTW, anyone know of a true chem dip anymore?  even the Berryman "professional" chem dip is about as strong as dish soap.

[Frank Angerano]

This is one I’ve used and like. It comes with the soak basket etc.   

[MarkinAR]

I'll check that one out, thanks.  I like that it says "Vapor harmful, skin and eye irritant.  Combustible".  I think the Berryman Chem dip says "safe for use on birthday cakes"

[Frank Angerano]

Lol your a nut! 

[Tahj]

Good writeup. I'd add that guitar strings are smaller than the torch tip cleaners. There is a video on ultrasonic cleaners that shows me some new tricks.

 

[Frank Angerano]

Thanks @Tahj i have heard about the guitar strings but seriously anyone who reads this that does not have a guitar string or torch tips should try to use the bicycle brake cable strand.   It’s perfect and has waves in it to help clear all walls of the ports.  

Ultrasonic cleaner is in my future for sure but I’m old school for now. 

[dee004]

Great write up Frank. X2 on the ultrasonic cleaner. It's amazing how well they work. 

[XWrench3]

i would warn to be careful with any rubber objects like diaphragms, o rings, needle tips, etc. some brands of carb cleaner will destroy them (i learned the hard way). so i don't soak any of them. i just wash them in the fluid they are supposed to be in contact with. i would add, that if the carb is extremely green and slimy, and needs to be soaked, the Yamaha carb cleaner (comes in a quart bottle) works great. 

[James Roscoe]

Great article. I like to use the Gunk cleaner with the basket also. I would love an ultrasonic cleaner and they remove dang near everything. I hate seeing what the ethanol in gas is doing to carbs now.

[Juan Gutierrez]

nice tips, thanks

[Jim Denton]

Nice bit of carbology! Helps take the what to many is mystery out of the process. 

[shar]

Great post, thank you!

[Frank Angerano]

Appreciate it thanks! 

[pablo Blake]

Thanks Frank i was actually just looking for something like this for my quadrunner i just grabbed except i dont seem to have any air/fuel mixture screws at all so it seems to all be internally controlled not sure where to tune it at

[Frank Angerano]

Take a look on the bottom of the carburetor you will probably see a small cap that sits flush. Under that cap is the air/fuel screw.   In some states the manufacturers are required to cap that screw for emissions reasons. Anyway that cap is easily and commonly drilled out to access the screw.  
Post a picture of the bottom of the carb and we will point it out.   

[pablo Blake]

When i get it out of the bike today i will take a pic of the bottom its pretty well packed in there, I can only really get some pics of the sides and what not with it in

Edited December 29, 2019 by pablo Blake

[Frank Angerano]

Ok no worries get it out and we will help you along.  

[Jim Denton]

Parts pic I had on the phone.  Might the red arrow be pointing to the area?

[Frank Angerano]

That is the area. Should be a flat cap there ? Take a pic of the bottom of the carb stand it up but upside down. 

[Jim Denton]

[Frank Angerano]

Yes. Stick a pice of small wire in there. It should be hollow. If so the you should be able to pop that brass cap out.  

[pablo Blake]

I'll get my borescope out and take a picture in a second before i even get it out, Ended up cleaning the whole garage instead of working on the bike. Also arranged all my tools just anything to not work on it at that moment.... 🙄

[pablo Blake]

Yeah i found it just in the most impossible to reach area. so only way to adjust is well its off the bike?  it looks like its screwed in quite far, like almost bottoming out i think can see a bunch of threads above it

Edited December 30, 2019 by pablo Blake

[pablo Blake]

Thought well i had the borescope out should get a pic of the piston. Looks pretty friggin caked and its all like wet got the borescope in with its pick and scraped a bit off and it was like liquid sludge