Your Carb on Ethanol

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It isn’t pretty.

I hadn’t done more than minor adjustments and external cleaning of my ’76 Kz900’s carburetors in probably ten years. The bike only sees about 500 miles of road time in a year – and it sits for months sometimes over the winter.

This gave the ethanol-laden “gas” we’re being force-fed time to do its thing.

Several things, actually.

First, the goop.clean jets, etc.

I have been working on cars and bikes for more than 30 years – since I was in high school, back in the ’80s. Only recently have I had to deal with a kind of alien plasma-ish grayish goo in the fuel bowls of my older (carbureted) vehicles. I suspect a chemical reaction is occurring between the ethanol (and god-knows-what-other-additives they put in it) “gas” and carburetor internals. It apparently dissolves rubber and plastic parts (such as gaskets, diaphragms, o-rings, float material, etc.) and the goop is the residue of that. Especially if the gas ages in situ. As it does in an antique or occasional-use-only bike like my vintage Kawasaki.

The fuel turns into … cue Dr. Jennings from Howard the Duck …something else.

I also found rust literally everywhere.

This I attribute to the water-attractive properties of alcohol. The 10 percent ethanol alcohol in the “gas” they’re force-feeding us. I’ve encountered rusty carbs before. In derelict cars and bikes left outside to rot. Never – until recently – in a garage-kept, pampered antique vehicle. Whether it is deliberate or inadvertent, the fact is that modern ethanol “gas” is very bad news for older, carbureted vehicles.

Bikes and cars.

Two of the four pilot jets were completely occluded (either by rust or goop) and even after soaking in parts cleaner for several days, they were beyond help. I ordered four new ones – still available from Mikuni. I was able to clean the floats (new ones are hard to find) and ditto the needles and seats (they are expensive to find).cleaned

Lucky for me I know how to take apart a carburetor – and put it back together. Therein lies the rub, though. If I did not know how to disassemble a carburetor and put it (them, in this case) back together, I’d have had to pay someone else to do it. And that would have meant a big repair bill, assuming I was able to find someone with the knowledge/skill necessary to tear down and rebuild 40-year-old carbs. Many people don’t have the skills – or the money.

Which is why this ethanol slow-drip death is exactly that. It is quietly killing off older, carbureted vehicles – whose owners can’t undo the damage caused by ethanol or can’t afford to pay someone else to undo it. If this is deliberate, it’s absolutely brilliant. A non-overt, non-legislative way to get rid of vehicles built before the electronic age, without computers (and black box data recorders) and which by dint of that are almost impossible to track/control and thus a pebble in the shoe of the powers-that-be. Almost all such vehicles came with carburetors. And it may be no accident – or at least, a convenient accident – that ethanol “gas” is deadly poison to carburetors, which unlike fuel injectors have lots of small parts made of materials that do not like alcohol.

At any rate, this appears to be the New Normal – if you own an older (carbureted) vehicle. Regular teardowns/cleaning of the carburetor(s). Using fresh gas helps. So does adding fuel stabilizer. And if you can, drain the bowls (and tank) prior to long-term storage. Even better, don’t use ethanol-laced “gas” at all if you can possibly help it. Unfortunately, many of us cannot help it. Real gas – gas that actually is gas,not 90 percent gas and 10 percent ethanol alcohol – can be hard to find, especially if you ride (or drive) outside the orbit of your local fill-up joint that has the good (the real) stuff.carbs off 2

Even still, you’ll probably end up doing the job I just finished doing – and doing it pretty often.

Rant off.

While I had the carbs apart, I decided to go a little richer on the main jets, from the number 122.5s I had in there before to 125s. Mind, my bike is modified. It has a big bore kit (with high compression pistons) a not-stock exhaust and it breathes through pods, not the stock air box. It needs more fuel. Yours may need less. But be careful not to go too lean. Go too rich and your bike may not run great, it might foul the plugs – but it won’t hurt anything.

Running too lean might.

Air-cooled old bikes especially may overheat dangerously as a result of a too-lean air-fuel mix.

You will also want to check synchronization (on multi-carb bikes) which is easy to do … if you have the right tool (a manometer, which measures vacuum/pressure; if you have a four-carb bike, you will need one with four “channels”; this is the unit I use). You’ll also need to check the throttle cable adjustment and (if you have an old Kaw like mine) the idle air bleed screws.

All buttoned up, the bike runs a lot better. The amazing thing, though, is how well it ran before. Even with two completely clogged pilot jets, and crud-encrusted internals.

Old Kaws are hard to kill.

Even though they’re trying hard to do exactly that.

Throw it in the Woods? 


  1. I see a lot of gripes about ethanol destroyed (insert whatever part here), but I personally have never seen one ethanol (please do not confuse with Methanol – big difference) related failure. I have run between 10 and 40 percent ethanol in dozens of vehicles for decades; various factory EFI systems plus Q-jet, Holley, and Edelbrock carbs. I also know a few racers that run 85-99 percent ethanol without issue.
    I have seen more than a few old cars with metallic/rust colored crap in the fuel lines and bowls, one of which had a brand new fuel tank and the owner swore he never put ethanol in the tank….may want to take care where you purchase your fuel.
    I’ve also seen unique problems with ethanol dispensers and underground storage tanks, which I suspect are related to electrical conductivity.
    But given my personal experience driving, racing, turning wrenches, and replacing underground storage tanks/piping/dispensers, I read articles like the above with a bit of skepticism…(I also have a class A CDL and am a licensed well driller :P)
    FWIW, my interest in ethanol is as an inexpensive race fuel (105 octane equivalent), I don’t think it is the greatest idea to mandate it as a fuel for everyone for a variety of reasons.

    • Hi DirtyB,

      My experience has been exactly the opposite. I’ve owned/been working on older cars and bikes for 30 years and never had the fuel system issues I currently deal with prior the introduction of ethanol. There is no question the alcohol is often corrosive to parts not designed to withstand it (which would be pretty much everything made before the mid-late 1980s). Hence the “ethanol compatible” rebuild kits – which help.

      “Gum” (varnish) is one thing. I’ve dealt with that – from stale/contaminated fuel – many times also.

      But this is different. Gaskets and o-rings dissolving. Gelatinous goo in the fuel wells.

      And it’s not just been my experience, either. (FYI: I have two friends who are master mechanics; they have seen/been dealing with the same things as I have.)

      And even if the stuff did not harm to older fuel systems, the fact that it’s a rent-seeking boondoggle ought to be sufficient cause to throw the whole thing in the Woods!

      • eric, my wife’s car manual says to never used alcohol content above 5%. So why would GM put that in the manual without reason? I once got (and the pump stated at least 10% ethanol)a tank of some clear, rank stuff from an HEB store. It sat in the tank overnight. The next morning going across town I lost every bit of the fuel. I had to stop and open a gate with the car idling on concrete. When I turned to get in(and this took only a few seconds since I knew I was losing fuel), the entire area around and under the car was saturated with fuel, oh what a feeling. When I got it on the lift, the plastic part of the fuel filter that was fairly new, was leaking so bad it wouldn’t even hold fuel in the line. I removed it and drained what I could into a plastic container. It was clear as water and smelled like hell. This fuel dealer gets a new tank of fuel every couple days so I don’t think it was significantly different from when it was unloaded. After a few minutes I notice my plastic bottle was melting, definitely not something you see with gasoline. Everyone in the place was asking the same question “What’s that smell?”. Supposedly…..fuel.

        • Yup!

          Here’s another:

          My Trans-Am developed a bad stumble/miss. Idled ok, but touch the gas pedal and – stumble/miss.

          I ended up tearing the carb down (after checking the obvious/external stuff) and what did I find? A chunk of plastic lodged in the left main primary jet. It was a piece of the (disintegrating) fuel filter, which was removed and replaced.

          • also could have been MTBE, it’s clear like ethanol and will eat many ploymers/plastics in a hurry plus has a horrid, eye watering, stench. Ethanol smells more like skunky beer.

          • Back in the 1990s when RFG (ReFormulated (oxygenated) Gasoline) came about there was a battle over the government choosing the oxygenate and the oil companies doing so. Pretty much ended up with government offering the choices of MTBE and ethanol. MTBE was already a by-product of the refining process or otherwise cheap and easily used. But in other areas ethanol was easier. I also recall state governments getting involved. Eventually it was found that MTBE was getting into the water supply. One of those unintended consequences of government action. MTBE was eventually removed leaving only ethanol.

      • Eric, several years ago in Oz people buying petrol at small servo operators had problems with rubber and neoprene gaskets in their engines dissolving, necessitating expensive engine rebuilds. Turns out toluene was being added to the fuel to stretch it further and to avoid paying some taxes. At about that time, customs here intercepted a tanker trying to unload 20 MILLION litres of this material in one shipment. That was about 20 times the yearly consumption of toluene in Australia at that time. This tanker was not allowed to unload its contents of toluene into Australia.

        Also turned out that these chemicals had smaller taxes than the additives that were used in petrol. So the operators added the illegal compounds to increase their profits.

        Your fuel may be altered by station operators to increase their profits. [ortho, meta, and para] Xylenes also have the same effects as toluene on certain motor parts.

        As a result of this, I only buy my motor fuel from name brands, except BP. BP are environmental bandits beyond any other oil companies on this planet.

        • say what?
          Standard “trademark” compounds in gasoline: Benzene, Toluene, Ethylbenzene, and Xylene.
          Toluene and Xylene are commonly used as octane boosters.

          • I am in the process of ministering to the Kz’s tank. I use the Bill Hirsch stuff (see here:,3276.html )

            It’s a three-step process:

            * First step, clean the tank using de-ruster.
            * Second step, etch the tank in preparation for sealer.
            * Third step, seal tank and let air dry for at least 24-48 hours.

            I’ve cleaned and etched the tank. Today it gets the sealer.

            If anyone out there hasn’t done this job before: Make sure the tank is dry before the sealer is applied. Or else it will not adhere properly.

            You can use a hair dryer after etching (which I do) to hasten the drying process. But I am paranoid/careful when it comes to stuff like this – and prefer to leave it to sit (and air dry) overnight before doing the sealer because there are just too many nooks and crannies in a bike’s gas tank to trust that a hair dryer got all the moisture out.

            Be sure.

            And, be patient!

    • DBB, I have serious doubts that pure “ethanol” is being produced from corn(Everclear). I think it’s something more like ether oxide that will destroy fairly much anything. I once had fumes from it vent out the shop door. A pickup 12-14 feet away had the rear light lenses milked in just a little while.

  2. It’s long been known that ethanol corrodes metal, rubber and plastic. This is why it is being used. Part of agenda 21 to make all our toys so expensive that they hope we get rid of them. So a21 are trying to speed up this process. Not just cars but also motorbikes, leaf blowers, boats, lawnmowers. The environmentalists help in this process as they are the “activators” of a21. All these greenie groups all state this: The middle class lifestyle is not sustainable. Note no mention of rich or poor lifestyles. Just the middle class.

    Any chemist knows of the destructive power of ethanol. Most of them work for a21 supporting companies. a21 want the older cars off the road, and this is one way of doing this.

    The greenies exhibit a hatred of all forms of life. By making the planet uninhabitable for us, it will take all cellular life down with it. I’ve always wondered why if greenies think humans are so bad, they don’t set an example by voluntarily removing their life from this world. Lead by example, you know.

    • All true, To5 –

      I’ve been searching for ways to counteract this – the effects of ethanol, that is. I’ve come up with stopgaps (locating/using “real” gas, being careful to keep the fuel fresh, use stabilizers, etc.) but none of this addresses the underlying problem.

  3. Ethanol must rank as one of the dumbest government “programs” and regulation ever (that is saying a lot, as just about everything they do lately is dumb).

    Over all federal vehicle regulation is insane. There are various “goals” set by these jokers. The biggest problem is, many of these goals are totally opposite of each other and are incompatible.

    For example, the “safety” nazis want better vehicle safety. Those devices mandated (like air bags and crumple zones) add weight to a car. In some cases, a lot of weight.

    Then you have the “efficiency” nazis who want better gas mileage. You have to REDUCE weight to gain mileage. But wait, cars have been getting HEAVIER lately to comply with “safety” mandates. So how are we going to comply with efficiency standards? Most likely in the future we will have majorly underpowered cars again.

    We would have that already if the auto makers haven’t managed to squeeze some amazing amount of horsepower out of really small engines. Imagine telling a car guy back in the early 1970’s that there would be 4 cylinder Mustang in 2015 with 305 horsepower. He would have thought you were crazy.

    Neither of these two (unwanted) groups has even considered what car buyers want.

    I was in a parking lot the other day with my dad, we were surrounded by mostly SUV’s, minivans and pickups. He commented, you would never think gas was this expensive during a really bad recession by looking at the cars parked in this lot (it was a casual sit down restaurant lot). We laughed, but its true. Americans are still buying what they want and need instead of what our overlords want us to. Just the fact that so many people drive SUV is the result of the stupid regulations of the late 1970’s. The government took away most of our large cars. Consumers and auto makers coped by buying light trucks instead of downsized cars. I have friends that I believe will never drive or own a car again, they love their trucks now. The government will have to ban light trucks to get them out of them now.

    I think most still put more stock in more metal between themselves and the outside, then any “safety” device like an air bag. So most seem to prefer “safety” over mileage and will pay for it.

    Ethanol doesn’t add safety nor efficiency. It lowers efficiency at a time when the government is demanding better mileage! And they are the ones mandating the less efficient fuel. There has been ZERO demand by the public for ethanol, in fact its the opposite as their engines are damaged. Our brain damaged government is doing one thing that goes against their other regulation.

    And consumers NEVER wanted any of it. AT ALL.

    Actually, if you think about it, Ethanol decreases “safety”. Ethanol can’t go through an oil companies pipeline, because it does the same thing it does to our engines. It gums it up. So all ethanol goes by tank car, via trains and heavy trucks. Pipelines are more safe when it comes to transporting fuel then heavy trucks and trains.

    Not to join the tin foil hat club, but the “elite” want the general public out of private cars for sure. There will be a day when cars are out of the reach of the general public due to mandates. Its no accident cars are getting way more expensive at the same time our income and salaries are in a free fall.

    Things are going to get way worse before things get better if we don’t turn the tide.

    • richb, you hit the nail on the head. In the SW, esp. Tx. cars are few and far between. Everybody drives a pickup(sorry, they ain’t trucks although some pull and haul loads almost like trucks these days, amazing it is)or SUV’s. Jeeps are also big here but I can’t figure that out….must be cheap to buy. Their quality sucks as does reliability and are expensive to operate with mostly very limited power….go figure. I won’t be buying a Fiat of any flavor, Ram or no.

  4. What I have been doing for several years now, to get around the gasahol problem, is I use 100LL aviation gas in my rototiller, lawn mower and motorbike. Aircraft gas is good for three years before there is any noticable deterioration. Just don’t use it in anything with an oxygen sensor. The lead poisions them after about 40 hours of run time.

    No more draining float bowls in the fall or de-gunking carbs in the spring.

    • Couldn’t agree more. Great stuff. I keep some around for my emergency generator and It lasts about a year in a regular sealed gasoline container without any problem. But it is more then $7.00 a gallon in CA., and you have to ^%#* about what it going to be used for if the FBO guy asks. “Oh, it is for my boat. No, never in a road vehicle, that would be illegal.”

      The best fuel treatment on the market is made by PRI, and it really works for storing regular crap ethanol pump gas long term and in my old bikes.

      • Garysco, I simply don’t store fuel long term now, except for some two-stroke that’s been mixed with Stihl oil and somehow stabilizes whatever that is that replaces gasoline. Do you know anyone who has used the diesel product? I normally use 100-170 gallons of diesel every day so long term storage isn’t a problem but truckers are always looking for something to increase efficiency or power or both. Anything that acts as a cetane booster, whether that’s its purpose or not is soitenly welcomed. Yours truly, Curly

  5. Love the KZ!!

    Some 4 carb bikes you can get away with a “2 channel” synch. The ZRX is one.

    You do the left pair and the right pair separately. Then you synch the two pairs.

    Just an FYI!!

  6. What about distilling real gas from the crap gas? Is that possible?

    Excellent article – I’m goign to have to start doign this, we have an 06 Kawasaki Vulcan that I’ll need to update and “rebuild” (Improve, new electrical, better lights, etc.)
    I’m turning into a curmudgeon and a … I dunno, Elitist, Survivalist, Old Timer? 😉
    I want REAL machines that WORK – not the cr@p we can get “for cheap” that’s mostly meant to be consumed and replaced.
    Hence dropping $1400 on the 98 Buick, new radiator and AC compressor. Next step: Better ergonomics (Been spoiled by the switches being RIGHT THERE – I need to see if I can jerry-rig a more modern steering wheel into the dash, to allow for new radio controls, turn signal smart switch, and cruise control. And since the airbag’s over 15 years old now, that might as well be replaced. And then we’ll look into a better engine and transmission ofer the next 5 years or so, and some useful spare parts…. And maybe some “null” V2V things, so it stays “road legal” and tells everyone it’s a an 18 wheeler, or maybe a tank… And it’s coming into your lane whether you like it or not!!! 🙂 )
    Add a diesel air horn, too…. Look into a 4X4 conversion with bigger tires… 🙂 Longer axles to keep the low profile…. But go to maybe a 24″ wheel or so!

    OK, that last part is probably impossible – the car is probably too BIG for 24″ wheels, too wide in the body. But like dreaming of the Pols getting sick and dying en masse, man’s got to dream… Even if it’s silly stuff! 😉

  7. There is one station in my area that sells ethanol free gas. I have been restoring my beloved 1968 Olds Cutlass S all summer (I don’t even want to begin considering the amount of money that I have dropped on her, it has been worth it though). I was ready to finally fire her up on Labor Day, and the LAST thing that I was going to do was fuel her up with that subsidized, crap ethanol laden gas.

    Anyhow, I drove to the station (15 miles from my shop), and had to wait in line for the most expensive gas in the tri-state area. There were two boats (ethanol eats expensive outboards for lunch), and one gentleman carrying two fuel jugs like me. He was also filling up his vintage car that he had lovingly restored all summer.

    The crowd around the lone ethanol free pump all agreed that ethanol may be one of the biggest rackets ever (says a lot considering). It is bad for the environment, bad for your car, TERRIBLE for your chainsaw / trimmer / leaf blower, results in lower gas mileage, AND (this is what really gores my ox) is heavily subsidized by taxpayers in the Corn Belt.

    I am running for US CONgress on the Libertarian Party ticket. I got four votes on Monday standing in line waiting on ethanol free gas. One of the first things I would do if I were elected (HA!) is present legislation to stop subsidizing ethanol and ethanol production. Let people pay full price for this junk AND THEN everyone will demand the real stuff!

    • Ethanol is mandated in the gasoline through a renewable fuel requirement and in specific areas of the country by oxygenate requirement. Removing subsidy alone won’t get rid of the stuff.

      The idea of the oxygenate requirement, RFG, was to trick old carburetored cars into running leaner. Of course after a few weeks most people had adjusted the fuel mixture screw to compensate, now 20 years on, just about everything left has been adjusted, re-jetted, or whatever it takes. Probably something like 99% of the vehicle miles or more are done by cars with O2 sensors and thus adjust automatically. Even a 1982 olds with QJet had an O2 sensor to control mixture. So now all that remains are the downsides of RFG and none of the benefit.

      It’s just another corn farmer boondoggle and always was.

    • Not to mention that the watermelons love the idea of renewable fuel, but “gasohol” has been demonstrated – by a high school science fair project – to be energy negative, i.e., require more energy to make than you get out of it.

    • If you live in an area that has one or more marinas, those often have REAL gasoline, as ethanol is even more deadly to marine engines and their fueling setups than land vehicles.


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