How to Clean a Motorcycle Carburetor, the RIGHT way.

I get asked about Carburetor Cleaning regularly both from readers and from friends offline. So I’ve decided to write a definitive guide for cleaning carbs the RIGHT way. So put your tools down for a minute, grab a beer, and give this a read. You might just save yourself a lot of headache and sweat.

Carbs come in many shapes and sizes. Single carbs, dual carbs, racks of 3, 4 or 6, V racks, carbs with ticklers, carbs with accelerators, carbs with asynchronous designs, and carbs that operate vertically. While working on some carburetors is more difficult (due to design) than others, they all share the same basic components, and the process of cleaning those components is generally indentical.


Make sure that dirty carbs are actually your problem. Lots of things can make a bike run poorly or not start. Weak battery, corroded electrics, old spark plugs, bad timing, low compression, mis-adjusted valves, dirty air filter, and plugged exhausts can all cause poor running. I’ll write an article on how to diagnose poor running conditions shortly, but for now – lets just deal with the carbs.


Once it has been determined that the carbs are the problem it’s time to get to it. Some racks of carbs are easier to remove than others. If you’re working on a newer model bike the rubber boots from the airbox to the carbs and the manifold boots from the carbs to the motor should be relatively soft and pliable. On older bikes however this is rarely the case.

First remove the fuel tank, seat, and side covers. Depending on your model of bike other parts may need to be removed too.  For many single cylinder bikes the carb can often be removed without removing any body work at all.

The bike below is a 1983 Yamaha XJ750 Seca with 4 inline Hitachi carburetors

1983 Yamaha XJ750 Seca Carburetors

Yamaha XJ750 Motor and Carbs

You’ll want to loosen the circle clamps on all of the rubber boots. Sometimes I’ll even take them all right off (carefully, without bending them too badly) so that they aren’t in the way.

Inspect the airbox. On many bikes it is bolted in place to tabs on the frame. Remove those bolts and try to create as much space as possible for the airbox to pull backwards.

Next, put the bike on it’s centerstand and straddle it facing forward. Put your right hand on the right-most carburetor and your left hand on the left-most carburetor and get ready to sweat. Sometimes you’ll be able to pull the carbs straight backwards nice and easy, but that is pretty rare. I usually end up rotating them up then rotating them down as best I can while pulling backwards furiously. This can really take some work and time, especially if you’ve never done it before. In real extreme cases where you simple can’t get the carbs to pull backwards out of the manifold boots I have a couple tips. These tips should only be used in extremely difficult cases when you have been struggling for an hour and simple can’t get the carbs to pull backwards out of the manifold boots.

Tip 1: Ratchet Straps – This is sort of a last resort, but it has worked without fail for me when I’m pooling sweat on the garage floor and the carbs aren’t budging. Wrap a ratchet strap around one of the outer carbs and put the hooks somewhere on the rear of the frame. Then slowly ratchet the carbs right out of the boots. Be careful not to pull them too cockeye’d or you could damage the boots. Attach a second ratchet strap to the other side if necessary. (Note: you can do this in the opposite direction to force carbs back into the boots once they are clean.)

Tip 2: Full Pull! – You should do this before you do the ratchet strap method above. Sit down on your butt along one side of the bike. Wedge one of your feet up between the forks and the front fender, then put both hands on the same outermost carb and PULL PULL PULL! This might not work so well if you’re short! Ha.

Ok, So The Carbs are pulled back

Chances are the airbox boots are all crammed up now. Do your best to rotate the carbs up and out from the boots and pull them out one side of the bike. Sometimes it’s easier to pull the carbs out one side than the other, so have a look to see if there are frame elements, motor elements, or hoses that may block the carbs from coming out on one side.

Also keep note of the throttle cable(s) and choke cable (if there is one). Now may be a good time to loosen the nuts that hold them in place and disconnect them.

Struggle just a couple more minutes wriggling the carbs out the side.

Ok, You have the carbs off the bike

Yamaha Hitachi Carbs

Make sure you brush off any loose dirt or grime, then flip the carbs over and remove the screws from the corners of the carburetor. Some carbs won’t have bolts in the corner and instead have a wire latch over top which can just be forced over.

Yamaha XJ750 Carburetor Bowls - Hitachi

Remove the bowls.

Hitachi Carbs Bowls Removed

If the carbs are real gummed up the insides might look like this:

Hitachi carb insides gummed up

It’s obvious that these carbs are all clogged up. Some carbs might not look so bad, some might be a lot worse. It’s always a mystery what will be inside the bowls.

Now it’s time to remove the floats. It’s generally a good idea to drench everything in carb cleaner (available at any autoparts store). Sometimes the pins will practically fall right out, sometimes they’ll be so stubborn you won’t think they’ll ever come free. But they will! Carefully push on the pin from either side. Sometimes a nail and a gentle tap from a hammer is helpful. **BE CAREFUL**, using force to remove a stuck float pin can break off the pin tower. If they are really stuck and you can’t seem to work them free here are a couple tips.

Tip 1: Heat – Adding a little flame to the float pin towers can help. **Don’t Burn Down Your Garage!!**

Tip 2: Pliers – Using pliers to gently clamp the end of the pin and push it through has worked well for me in the past. **Don’t break the towers!!**

Once the float pin is out you can remove the floats, the float needle, and unscrew the float jet screen.

Yamaha XJ750 Float Jet

Set everything aside. Next remove the main jet, pilot jet, and idle jet (if there is one). They should come out easily with a flathead screw driver.

Removing Main Jet and Pilot Jet from the Carbs

Set them aside.

Next flip the carburetors back over and remove the caps. Underneath the caps is a rubber diaphram with a spring. Sometimes the caps have a tendency to shoot off the top, so be very methodical when removing the screws. Other times the cap tends to stick down until you start to pry at it, then it shoots off, again, just be cautious and don’t loose any parts.

Carb diaphram, slide, and spring.

Next you’ll want to gently pull the slides up out of the carburetor body. You can gently pull on the rubber diaphrams, but be very careful not to tear them. If they don’t come up easily stick your finger into the carb intake and push the slide up with your finger. You can also gently pry it with a screw driver (gently). If it doesn’t want to budge don’t force it. Instead finish reading this article and pay attention to the boiling tips further down.

Main needle and throttle slide.

Now your carbs should be pretty well emptied out. If the throttle on the bike moved fluidly and smooth there is little reason to do much to the carb bodies themselves. However, if the throttle was real sticky or frozen there are a few things you can do to free it up. Sometimes just drenching all the throttle components on the carbs and letting it soak is enough, other times it is not. I generally try not to break racks of carbs apart. It isn’t often necessary and can be confusing to put everything back together in the right places. Also, the little rubber connector hoses and o-rings have a tendency to crack or leak if you mess with them. If you can’t work the throttle back and forth until its smooth have a look at the boiling tips further down.

Keep it Neat

Organization pays off.

Carburetor internals organzied

Clean the Main, Idle and Pilot Jets

Hold each jet up to the light and see if you can look through it. The idle and/or pilot jets have extremely small holes so make sure you are looking through them straight. If you can see through the jet it isn’t clogged. There could be a little gunk built up around the edges so spray them down with carb cleaner and let them sit a bit.

If you can’t see through the jet it is clogged and needs to be cleaned. Always try the easiest things first. Here’s an ordered list of a few things you can do to clean the jet.

  • Blow through it. – Rarely works, but hey, who knows.
  • Compressed air. – Force 100 pounds into it. Works occassionally. Make sure to hold the jet tightly so it doesn’t go flying across the garage. You might put the jet back into the carb body to hold it in place for this.
  • Soak it in cleaner. – When I first started cleaning carbs I thought carb cleaner would be the magic answer. It isn’t. In fact, I hardly ever use carb cleaner any more, because it simply doesn’t do a very good job of anything but removing varnish from the bowl and slide. But try this.
  • Poking it through. – Collect a few different diameters of needle like objects. A wire from a steel bristle brush works well, a bristle from a broom works well, a baby pin, small sewing needle, etc. Very gently try to poke it through the jet. If you are using a metal needle use caution, brass jets can scratch and deform easily.
  • Boiling! – This works better than anything. Toss the jets into a pot of boiling water and let them bounce around for a couple minutes. When you pull them out blow some compressed air through them and you’ll most likely be good to go.

Some idle jets can be real tricky and never seem like they’ll be cleaned out . . . Just keep working at it, I’ve never met a jet that couldn’t be cleaned.

Cleaning the Choke and Air Mixture Screw

Air mixture screws have a tendency to strip or break. If the carbs were real gummed up you might find that the air screws are stuck. Don’t force them, if they don’t want to come out, just leave them for now. It is fairly rare that these screws will need to be cleaned because they are above the float level. If you can get them out just wipe them down with carb cleaner and spray some through the jet.

Cleaning the Slide and Needle

These are easy to clean. Squirt them with a bit of carb cleaner, wd-40, or anything similar, then wipe them down with a rag. Once the varnish is gone they’re good to go. Sometimes they get heavy varnish on them which I will scratch off carefully with a piece of plastic. Scratching the slide and needle is a BAD thing, use caution.

Cleaning the Carb Bodies

Use the same squirt and wipe method noted above. Most of the time the other pressed jets and passages in the carburetors won’t be clogged. But if the bike has been sitting a real long time with squirrels in the airbox it is certainly possible. Us a compressor to blow some air into every passage you can see. Listen for the air coming out the other side. If no air compressor is available use a can of WD-40 with a straw attachment.

If some of the pressed jets are clogged it can be difficult to open them up. There are a few things you can do.

  • Carb Dip – Most autoparts stores sell carb dip. It comes in a can similar to a paint can and is a VERY harsh cleaning agent. Soak the entire carbs in this dip. This dip can eat at rubber and plastics if they are submerged for too long, so try and remove everything you can from the carb bodies before soaking them. Once you pull them out swish the carbs around in a bucket of water to clean off the excess dip, then hose them down with WD-40 to get rid of the water.
  • Boiling in Water – Not many people do this but it is by far the best way of cleaning carburetors. Dropping the carbs into a pot of boiling water will instantly free up stuck slides, throttle plates, and other frozen parts. It will also loosen the dirt and grime clogging up pressed jets and other passages. Just make sure to dry the carbs thoroughly with compressed air or the sun afterwards.
  • Boiling in Lemon Juice – There is NOTHING BETTER at cleaning carbs than a giant pot of boiling lemon juice. The acidity from the lemons eats through everything; gas varnish, oil build up, dirt, grime, etc. Sometimes I won’t even bother doing anything but this – I’ll just remove the bowls, remove the caps, then drop everything into the pot and let it sit for 20 minutes (rotate them a few times). The one caveat to doing this is that you’ll want to wash the lemon juice off the carbs as soon as you pull them out. So have a bucket of water ready, or a can of WD-40 to hose them down. Also note that the acidity has a tendency to put a dull finish on the aluminum bodies of the carbs. This isn’t a problem in most cases, but if you must have everything shiny be prepared to do a little scrubbing and polishing afterwards. It may sound weird, but trust me, I just saved you LOTS of time. (Most dollar stores sell 1/2 gallon jugs of lemon juice, so buying a few gallons will only cost you $6. Plus you can put it back into the bottles afterwards and save it for next time.)

Cleaning the Bowls

This is pretty straight forward. Use any of the methods above to tranform your varnished bowls.

Dirty Carb Bowl

Clean Carb Bowl

Most carb bowls are simple, just clean them up and they are good to go. But I picked this Hitachi’s for photos because they have a jet built into the bowl. You can see the ‘fifth’ hole along the edge of the bowl, that is actually a thin passage that extends to the bottom of the bowl. This is for the idle jet and is extremely important. If these passages are clogged, the bike won’t stay running, period. Use the same poke, soak, and boiling methods outlined elsewhere in this article. Not all bowls have these passages, only some, if your’s don’t – good for you!

Once Everything is Clean

Now that everything is clean it’s time to put it all back together. Take your time and make sure you put everything back where it came from. WD-40 is your friend. When screwing in the jets don’t over do it, they only need to be seated and snug, do NOT use any force putting the carbs back together.

Hitachi Carbs from a Yamaha XJ750 Cleaned!

If the bowl gaskets got goobered up you can put a little RVT on them. So long as the float needles are still in good condition leaky gaskets shouldn’t be an issue. However, prudent carb tinkerers may want to order replacements if necessary.

Once the carbs are back together stuff them back into the bike!

Completely cleaned and reassembled carbs.

Extra Notes

  • Rebuild Kits – This guide did not mention rebuild kits until now. Rebuild kits (consisting of new gaskets, jets, needles, etc) can be purchased for nearly any bike, both old and new. 95% of the time these are NOT needed. I have rebuilt enough carbs to block off main street, and only once have I used new parts. ONCE!
  • Carburetor Adjustment – Carburetor adjustment, setup, jetting, and synchronizing is a whole encyclopedia waiting to happen. Those topics are not covered in this article, but I will address them in future articles.
  • Carburetor Polishing – External carb asthetics will be important to some, and not to others. Cleaning is all I am covering here, this will be addressed in the future.
  • Work Space – Make sure you have lots of space to keep organized. I also like to work on a wooden surface because it absorbs the spilled gas and cleaners rather than pooling.

That’s it! You’re Done!

I’ll continue to write a couple more related articles about diagnosing carburetion issues as well as the proper way to adjust, jet, and tune your carbs.


By ef

Hey, I'm Evan and this is one of my motorcycle sites. You can find more about me on my homepage, or visit me on Google Plus: +Evan Fell


  1. Hello, I have a Yamaha silverdao 1700cc, 2007.
    The bike has been sitting in the garage for the last nine months without starting, do you think the carb. Should be cleaned? Any thing else should be done before that?
    I appreciate sharing your experience.
    By the way the bike doesn’t start right now.


  2. Hello Evan
    Fantastic article,struggled for a long time to get info like this.
    I live in south Africa and not many guys here helps like you did.
    FYI-I have a 1985 750 pre-sling.


  3. Your article gave me the confidence to do this. I had been putting this carb clean off for 8 months just hoping my bike would start and run properly. About 3 or 4 hours later and the job is done and my bike runs. Thanks so much for the time you put into this article. You’ve turned my useless, space-wasting, rusty old bike back into the machine I fell in love with.



  4. I just bought a 82 suzuki gs650g that needs the carbs cleaned but i have not done it yet but i will be doing it very soon but without your help i would not have known where to start so Thank-You so much & i will be doing the carbs soon.
    P.S. What kind of lemon juice do you use??


  5. I have an 1988 yamaha radian 600 with almost the same set of carbs as that. Im going to try boiling them in lemon juice to clean it, but I cant seem to find a rebuild kit for them. Would you know any good sites to find one?


  6. Man super cool write up, I have a 1992 Vmax that runs like you no what, popping through the crabs and some back firing. To have the carbs clean cost almost $450.00 to $550.00 at a local shop.
    I going to try this my self. But 1 carb at a time. Thanks for right this. I did try sea foam 3 time it did not work for me.


  7. Thank you so much for the great tips. I read your blog because as a young girl of 12 years old in 1972, I was call the carburator queen. The locals in my neighborhood would have me clean their carbs. I used the boiling method and wd 40. I really like the lemon juice idea `thanks~
    Since people cut grease in french fries with the vinegar, do you think I could use it in place of lemon juice. I was thinking maybe 1/2 cup to a gallon of water for a boil. I look forward to reading more of your tips. Thanks


  8. Thanks for this article. I am about to tackle the carbs on a 96 Magna that has been sitting poorly prepped for several years.

    The lemon idea is eco-inspiring.

    Now, if you have any thoughts on cleaning a rusty tank, my day will be perfect!




  9. Hi just purchased a 1982 xj750 maxim and love the bike but only one issue at WOT bike runs like a beast at lights the bike just shuts off and I have to open the idle to get it to start back up I dont know if its carb issue or I need to adjust something im new to the bike world and I want to tackle the carb job I would have a shop do it here in Houston texas local shops charge me about $500 to do it and I dont have the money for it im not a mechanic not even a shade tree mechanic but I know my way around the tool shed im 24 yrs old and im worried about throwing my investment to the trash I would like some words of wisdom please


  10. Hey Jonathan,
    Sounds like your primary jets are plugged. This is easy to fix. I would clean the carbs paying close attention to the jets. Don’t touch any of the settings just flip them over and pull out the jets and clean them. Inspect the carb for any loose debris in the bowl.


    Jonathan Reply:

    Hey vic thanks for your reply I really appreciate your time yo answer my question and I have looked into cleaning the carbs I took the bowls the other day just out of impulse to my surprise they look clean to me no crud what so ever just small amounts in the corners which im guessing is the hardest to come out? I was hoping for dirty carbs I didn’t want to touch anything else so I put it back together so if I understood correctly just take the bottom of and clean them? Like the jets etc…?


  11. Hey Jonathan.
    You will have to pull the carbs . Flip them over and pull the bowls off. Even a little dirt can plug jets. Take off the float and take out the needle seat. You will find a variety of jets and things . UnScrew them and put them neatly on your work surface. I usually have a blue shop towel to lay them on as they won’t roll away. Take a look through them. they should be clean inside. If they look dirty follow Evans advice and carefully slide a wire through them. Put every thing back together. It is easy. You can’t mix them up as they only go in one way. If you are worried take pics before you strip things down.
    Don’t take anything off except from inside the bowl.



    Jonathan Reply:

    Ok vic that sounds easy enough I really would like to get back on my bike it was just a bit scary when on the freeway it feels like it will do 65 all day but once you hit traffic it will sputter and shut off at about 30mph I have to choke it and kick it in neutral it will come on after a couple of tries but it will just sputter and it gets up to speed but sputtering not with the power I started off with


  12. Awesome I had the same problem with the idle after I replaced the carb joint conn yesterday. Now I feel a lot more confident about my cleaning project. Thankyou!
    81 xjseca 750 and I


  13. great article … I’m preparing to clean the carbs on a 1994 zx7. I can wait to try the lemon juice !!


  14. Great article! Makes me anxious to get my fuel tank off and start working on it. I have a 1997 gsxf 750 katana and for some reason the idle just varies a lot. i mean it will go between 1200 to 2000 . Do you believe its clogged carbs or just a vacuum leak? Thanks a bunch !


  15. Awesome how to! Much appreciated. The only thing I can’t get off is the needle seats, which I thought would be the easiest. Any tips? I’ve sprayed them with WD40 and am using a 10mm socket (b/c that seems to grip better than a 10mm wrench). But no joy on any of them.


  16. Evan, what a great article. Wish I had seen you blog before I did my carbs on a Kawasaki Zephyr 1100.

    If anyone is interested in the carbs for the above mentioned model, I have posted a lot on this site.


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  18. I own a 1982 Yamaha XJ650 with that worthless YICS system. I probably purchased 7 cans of carb cleaner and still the piece of junk won’t start. I purchased 4 float needles and seats and took 5 hours to clean and install the float needles and seats. End result number 2 carb has gas pouring out the back of the carb where the main needle is. I have NEVER seen such a piece of junk in my life as the XJ650 is. I had other Yamaha’s like the Exciter and 650 special. I had to bang the starter on Exciter to get it going. That’s it.


  19. I tore mine open and got all the Pilot jets out except for one, I dont know if you run into this a lot or not, but I dont want to reef on it and damage it more than i already have. I was just looking for tips. or maybe ways to clean it as much as possible without actually removing it.


  20. I really appreciated this article I know I have one carb that sticks, but the whole bike has been sitting for years. I really want to get it going again. It ran fine except for the one carb sticking but sat for years. Now I’m excited to get into it. Thanks


  21. ive got an ’82 xj750 and the air filter is under the seat, take off the seat and theres a screw or two to remove the cover and then your air filter is ready to pull out


  22. Hey Evan,
    Your breakdown really helped. Just a quick question though. Will boiling the carb hurt any gaskets? I have mine broke down fairly far, but it has been clean so far on the inside. I don’t want to


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  24. about to jump into a 99 Shadow Spirit 1100 w clogged carbs and rusty chrome, been sitting. Googled cleaning carbs & your site popped up. very, very helpful. Going to boil in lemon juice, then wipe down and blow down. thx


  25. A great read and a big help to most however on my carb off of a Suzuki gs 1200 bandit it has seized up on the throttle control mechanism. where the throttle cable attaches to the carb? any advise to un seizing that will be a great help thanks.


  26. I’m not sure lemon juice removes varnish or grease from carbs but it did clear the jets on my 94 Honda F2. I’ve had clogged jetting problems for 12 years with my Honda F2. Thanks! you saved me hundreds of dollars. The bike was almost unrideable before the carb clean but it’s fine now.


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  28. Thank you Dawn for posting your cleaning on this whole situation. At first I did not want to take resisnopbility for the events that have taken place with Joe and Mark. After reading your post I started to cry and I knew that I had to take responsibility for my part in it. Peace Love and Light to you on your pathGlen


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