How to Clean Motorcycle Carburetors


Introduction: How to Clean Motorcycle Carburetors

About: Hi! I'm Star Simpson! I'm a real me! See more at []. photo by [ Jeff Lieberman] ( stasterisk - my name is Star, and when I was 13 I ...

This free motorcycle was sitting in David Durlach's garage for 20 years.

David eventually tired of it, and gave it to Prank, who cleaned out the brake lines and added a new battery. Then winter happened, and it sat in Deepest Darkest Somerville for a year, until prank graduated and moved to California, and I was given care of the motorcycle. I wheeled it back to MITERS to see if I could get it to work. A new battery, some carb cleaner, and a little bit of hope, and it started up! Yum, throaty rumble!

With visions of a cross-Cambridge joyride followed by summers of long-distance road trips, we took it to the road and kicked it into gear.

But, every time the gas was added from the gas tank, the 'cycle coughed up and died. Oh well.

I emailed the MIT Motorcycle and they said "clean the carbs". With a monkey wrench and a vague idea of what I was looking for, I did all of the following. Now they sparkle!

Step 1: Get the Float Bowl

There are some haaard to reach screws in there, man.

Get them all out, until the float bowl is in your hands.

Step 2: Scrub

I noticed all this brown gunk in the bottom of the float bowl. How to get it out?

I grabbed a tuft of some really fine steel wool, and used a cheap pen to rub it into the areas to small for my fingers.

When it looked shiny, I sprayed in some carburetor cleaner I picked up at the gas station across the street.

Step 3: That's It!

Screw the float bowl back on, and you're done!

Vroom vroom, enjoy!



    • Water Contest

      Water Contest
    • Oil Contest

      Oil Contest
    • Creative Misuse Contest

      Creative Misuse Contest

    57 Discussions

    The easiest and most thorough way to clean a motorbike carburettor is by using an ultrasonic cleaner. More info:

    Ultrasonic cleaner with a bank of 4 motorbike carburettors.jpgmotorcycle carb cleaning.jpg

    Alot of southern and western states are a little looser on the title part. See if you can find out who the last registered owner was, then apply for "lost title" in their name. In some states you can get salvage, builders, or bonded titles. If you have friends or family in one of those states, it won't be too hard. Good luck. I've owned a GS bikes. Change the oil regularly, turn the fuel "off" when parked, and it should last forever.

    i have a 1978 gs750 and my fuel swithc say's " pri, on, res" which one should i set it to in storage...?

    I had the same question. The dealer I bought it from said leave it on prime and run it til it dies. That should leave the carbs pretty empty over winter.

    You should have two inlets on the petcock one goes to carbs for fuel flow other hooks to vacum source to open petcock set to on to store turn to pri to start and then set to run ands let i run down the road with no vacum at petcock fuel will not flow Yam, Kaw, and Suz all use thois set up on biogger bikes

    no fuel off... i guess with my model the air box was converted to pod filter (which is another mess in itself) but the air box had a vacuum to prevent the gas from leaking.... i have to figure out how to put the airbox back on now..... tried once this summer, but couldn't get it to fit with a 1/2 full tank on... hopefully i can drain it this weekend and then try this winter to put the airbox back on.

    the person before me (a friend) took the airbox off for more power, but never rejetted just played around with the carbs for a 'better' air flow... i beleive putting the airbox back on will fix a ton of stuff.... or a re-jet.

    thank you all

    Maybe you could install your very own on/off valve in the fuel line? Not sure how your line is routed, not familiar with the bike, OR you could just drain the tank and run the carb dry after that.... It just seems to be a surefire way to get it all out of the system and there will be no buildup since the fuel isn't there.

    You could also look at it from another point of view too though - since there is no fuel there the seals might dry out and make the fuel system start leaking.

    I guess maybe overall the best thing to do is to run the engine a half hour or so every month at LEAST to insure that everything stays varnish and leak free.

    thanks for the info.. this bike is more work than play, but i love it. i make sure i run her all the time even for a couple minutes just to make sure. i also swear by Fuel Stabilizer now. i had a guy that was gonna check my bike out and fix it all nice, but he got into a terrible car/motorcycle accident and is still in the hospital. i work on the bike everyother weekend, the more i do the more i'm learning. but maybe i will try just installing an off valve?

    Running the bike for a few minutes a week and using fuel stabilizer is a great idea!
    Make sure not to let it sit for over 4 or 5 months without running it. Gas these days isn't what it used to be - you may wind up having to drain the tank and putting fresh gas into it if the stabilizer doesn't do its job.
    I think running it a few minutes a week will do the trick and never put too much gas in the tank, at least not more than you will burn in a week or so. Good Luck!

    My book on my yamaha says on or reserve only lets gas pump thru carbs when motor is turning over or running.Prime lets gas flow constantly.So either on or reserve works.TO be safe I would drain gas from tank and carbs if storing for a long period.

    I fiddled with the fuel system,res allows the fuel to flow,pri doesnt .Anyway I have a problem with my carbs,I believe I cleaned all the jets ,the bike has been sitting for quiet sometime.Itll start when I put fuel in the barrells manually,although it wont hold.

    Hmmmm? I'd say there should be a fourth option. Disconnect the fuel line from the carb. Then try all the settings. If one of the settings doesn't let the fuel flow out, then go with that one. If you're just putting it in (warm, dry)storage for 4 or 5 months, it shouldn't be a problem anyway. Some folks would disagree with me, but if I were going to store it for a year or two, I'd run it completely out of gas. Or, you might just look into good fuel stabiliser, and keep the bike full.

    How true. We've got some non-numbers matching seventy-year-old-plus machines hanging out at our place. We're hoping we can get some Colorado titles for 'em once we fix 'em up. Last registered in Arizona 30 years ago and the paper trail is sketchy, so hopefully the law isn't too picky here. The '39 probably has a half a million miles by now, just needs a ring job, but my dad had to park it since he couldn't afford that.

    In Virginia, you can apply for a 'Title of Abandonment' or a 'Mechanic's Title'. These are used for instances where vehicles are abandoned at shops and garages. The owner disappears and the machinist is left holding the bill. I have gotten so many cars and bikes from garages that way. Usually takes about $30 and a couple of weeks while DMV researches the last owner through the VIN# and attempts to contact them.

    I looked it up, and same here. "Lost title" and "mechanic's title" are both ways to get a new title on the books, depending on whether you (or whoever gave you the bike) lost the title, or it was a case of abandonment.

    My bike has been sat in my grage for about 2 or 3 months and won't start. I've tested the spark plugs and they all wok and i've drained the tank and put fresh petrol in just to be safe as i've been told by a few people about petrol going bad. When i manually put fuel in the engine fires up but doesn't hold on to the power. Could this be my Carburetor? The fuel tap was on reserve, would this mean my petrol was constantly slowly dripping in which would cause the carb to get bunged up with sludge and gunk?