Ethanol: the carb killer

Nick_Brox

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Note: I have a tendency to wall of text some of these. Please scroll to the end of the post if you would like a brief summary.

As most of you have probably noticed, over the last decade or so, nearly every gas station in the US now has stickers that say 10% ethanol has been added to unleaded fuel. For most people, they can simply ignore this. The reason for this addition was to “reduce cost of fuel”, but really it’s a whole government racket between farmers and it technically zeros out due to various reasons. I won’t get too into that, but there is a plan to eventually move to 15% ethanol content which could be very bad for even slightly older cars that were made before 2001.

A lot of people are unaware of what any of this means, and how it is impacting things like lawn mowers, generators, older vehicles, and our beloved Honda Twins. Luckily for all of you I have researched this fuel for a couple papers in school, and have found what has been a reliable solution to the problems ethanol can cause.

Getting into why ethanol is such a big bad thing for us requires some basic scientific knowledge. HOORAY SCIENCE!
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Ethanol is an alcohol, typically made from corn or other sustainable sugar sources, that increases detonation of fuel in your engine with the added benefit of burning colder than gasoline. Adding a small amount to fuel doesn’t really make that much of a difference overall, but due to its properties this alcohol can be detrimental to old rubber, steel tanks, and carburetors.

Rubber fuel line and o-rings are typically Nitrile when dealing with older vehicles. These work great for petroleum based oil and fuel, but are not resistant to ethanol. Synthetic Rubbers like Nitrile require oil. Dry rot is a result of the oils evaporating out of the rubber and will result in hard, brittle lines and seals that will leak and cause all types of vacuum issues. There are also some vehicles that use rubber or plastic float bodies that can fail due to ethanol. Since ethanol is an alcohol, it can permeate the Nitrile and then evaporate, taking the oils with it and speeding up the dry rot of Nitrile. It also dry rots seals that would typically not be an issue due to heat, light, or air exposure. This dry rot effect is why my ‘73 240z left me stranded on the side of the highway in El Paso on my birthday. It ate through the membrane in the mechanical fuel pump!

The fix for this is to replace any fuel line with neoprene, tygon, or nylon lines. Neoprene is the more common rubber line found on most fuel injected cars. Tygon is a clear tubing used on brake reservoirs, new small engine fuel systems and even aircraft hydraulics, and most large manufacturers are now using nylon fuel lines. All three of these have better chemical resistance than Nitrile, with Neoprene fuel line being the cheapest, easiest to work with, and easiest to find.

For gaskets and O-rings many newer offerings are butyl or neoprene and will stand up to ethanol okay. They are also cheap enough that replacing more often isn’t a problem. You can go crazy and get coated o-rings that cost a fortune. Or, if you’re willing to spend in the mid-range, get a kit with various sized Viton o-rings. These will stand up very well against ethanol, and are even recommended for E85 applications.

So that solves one problem that ethanol presents. What about the others?

Ethanol is an alcohol. Alcohols are made by the fermentation of sugars. Ethanol that isn’t perfectly pure can leave behind those sugars or other contaminants when it evaporates causing a gooey mess inside carbs, tanks, and filters.

Why does it evaporate or collect contaminants though? Since Ethanol is a chemical compound made by fermentation, it’s molecules are “dry” meaning that it will attach to any water or moisture. This causes it to then separate from the gasoline since oil and water don’t mix. Once it separates Ethanol will evaporate faster than the gasoline. Leaving behind any sugars or contaminants turning fuel in your carbs into a gummy mess. Yuck!

This is also a problem for old steel tanks. Ethanol has a slightly higher density than gasoline, especially when it soaks up water. So once it separates, the ethanol will sink to the bottom of your tank, taking the water with it. This will result in rust on the bottom of you tank. It can also mean that even by sitting overnight or a couple days the fuel in your float bowls will separate making it harder to get your bike started. If left over the winter, this can cause corrosion of aluminum parts leaving a white chalky crust on everything in your carbs.

It is practically unavoidable with a car, bike, or small engine, because any moisture in the air will be absorbed by the ethanol. There is also no real way to know that the fuel you are getting from any gas station doesn’t already have some water in it. This is compacted by heat and condensation. So what do you do about that?

Well, you could get lucky and happen to live somewhere that ethanol free gasoline is available. I am in a more rural area, with a lot of farmers that prefer to use it. (Funny that the people that grow a ton of corn to make ethanol, prefer not to have it in their gasoline.) That means there are a couple stations that offer ethanol-free. However, it is usually more expensive, and I have to only fill up at those locations.

Instead I found this.

http://www.starbrite.com/item/star-tron-gasoline-additive

This fuel additive is specially formulated to combat the bad behavior of ethanol, and it is honestly the only one that has worked well for me. I am in no way affiliated with the company, I just discovered it ten years ago and now swear by it for any ethanol related issues. Sta-Bil does make a better product for storage, but doesn’t improve overall performance. The reason an enzyme treatment is important is because it will stabilize the ethanol in the mix. Preventing separation, and converting any impurities. I have used it in my ‘73 240z, ‘77 VW Bug, ‘69 VW Bug, 2005 CBR, lawn mowers, weed whackers, generators, and anything else with a carb. This spring I started my mower up after it had sat with a full tank of E10 unleaded since Nov. with zero issues.

It is likely that the E15 move will happen, and when it does it will create a lot of problems for everyone. Hope this info was helpful or interesting!


***I don’t feel like reading all of that section***

Ethanol is an Alcohol additive to fuel, usually corn based, that increases the octane rating. However, most older vehicles are not built to withstand the harshness of this chemical and it can accelerate dry rot of fuel lines and rubber gaskets/seals. It also separates from gasoline while sitting and is hygroscopic. Meaning it will absorb water and cause rust or corrosion to tanks and carbs. It can also gum up when it starts to evaporate because it has sugars in it.

I use a product called Star Tron to stabilize fuel that contains ethanol and have had great results over the past ten years.


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I use non-ethanol gas exclusively in my Honda. Luckily, there are 3 stations that sell it within about 5 miles of my house. I also use it in my lawn mower.

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I use non-ethanol gas exclusively in my Honda. Luckily, there are 3 stations that sell it within about 5 miles of my house. I also use it in my lawn mower.

Ditto.

All the cycles and small engines get ethanol-free Regular.

Like you, I'm lucky to have it ethanol-free in all grades less than a mile from work at Cenex.
 
Ditto.

All the cycles and small engines get ethanol-free Regular.

Like you, I'm lucky to have it ethanol-free in all grades less than a mile from work at Cenex.

That’s nice! There are only two spots near me. One is only a couple miles away, and the other is about ten. Near work there is nowhere to get it though.
 
I only have 2 places "near" me - rural life - and one is an old-school, curmudgeonly guy who is very proud of his 89 octane leaded fuel at $5.99 a gallon and his premium leaded 93 octane at $9.99 a gallon. The other place, a new Circle K store, only has non-ethanol unleaded regular at 87 octane for a fair price, but my 11.6:1 CR wants premium.
 
I only have 2 places "near" me - rural life - and one is an old-school, curmudgeonly guy who is very proud of his 89 octane leaded fuel at $5.99 a gallon and his premium leaded 93 octane at $9.99 a gallon. The other place, a new Circle K store, only has non-ethanol unleaded regular at 87 octane for a fair price, but my 11.6:1 CR wants premium.

Yeah, the only place that has non-ethanol high octane fuel near me is $4.50 a gallon. I would suggest using the Star Tron stabilizer for that bike. It would last quite a while if you’re just using it on a motorcycle. Circle K most likely has it available.
 
I've been using Stabil in the fuel I buy for all my bikes and power equipment and have had zero issues. I only have a couple of gas cans and as such, I buy 5 gallons of premium to keep on hand for my red 450 as the tank is only 1.8 gallons, meaning if it's on reserve when I get back from a ride - which happens often with only 1.4 before reserve - then I have to fill up at home before leaving since the closest station to me is over 7 miles away. So, my power equipment gets to enjoy premium fuel too, with a dash of Stabil in it.
 
I've been using Stabil in the fuel I buy for all my bikes and power equipment and have had zero issues. I only have a couple of gas cans and as such, I buy 5 gallons of premium to keep on hand for my red 450 as the tank is only 1.8 gallons, meaning if it's on reserve when I get back from a ride - which happens often with only 1.4 before reserve - then I have to fill up at home before leaving since the closest station to me is over 7 miles away. So, my power equipment gets to enjoy premium fuel too, with a dash of Stabil in it.

Stabil is better for long term storage, and has been proven to be by labs and independent studies. If it works, I wouldn’t switch. Much better than nothing.
 
My bike - the only one running at the moment - and all of my power equipment sits for longer than most people's stuff. I have yet to mow this season, though it's finally time since we started getting rain, and the last time I mowed with the garden tractor was late last year. It does not have a fuel shut-off, though I'm probably going to put an inline petcock in it this season. I run it every month or so in the off-season to keep the battery up and flow some fresh fuel through the carb and it's been fine, and the Honda walk-behind mower has a petcock so it gets run dry and as always, starts the next year on literally the first pull. My generator gets run every 2 to 3 months but also has a petcock and gets run dry, but the fuel sits in them longer because of limited use (hey, I hope we don't have another hurricane come through anytime soon, but it handled everything but the a/c for 4 days the last time). The 450 sits sometimes for 3 to 4 weeks without being run, but I turn on the petcock in between for a few minutes to refill the bowls to avoid any stale fuel. Can't run it out fully when shutting it off in between rides because the fuel line arrangement has one line significantly longer than the other so it woulds run on one cylinder for a long time to run that one out.
 
Any time I fill a gas can I always add the appropriate Stabil.

Non-ethanol gas and Stabil mean I never have to disassemble any of my small engines to clean clogged jets or gummed-up floatbowls.
 
That's been my experience so far, since a buddy of mine told me about Stabil about 8 years ago.
 
Never had a problem with ethanol in my motorcycles but I don't let them sit for more than a few weeks without running them. Also use seafoam a few times a year. I have had problems with water in the fuel for my 25hp outboard now and again.
 
Our problems with ethanol are far worse than what's been brought up so far.
The stuff is death to our valves and valve seats, they get decayed like bad teeth after a while.
Now seats can be reground of course, but on one beloved model (CB/CL450 DOHC) this often times leads to worse issues of valve extrusion.
At least 50% of the 450's I've seen have (probably) ethanol related damage in this way.
 
I didn’t know that. I wonder if any of the additives out there would prevent this. Are the valve seats on the 450 replaceable?
 
...... Are the valve seats on the 450 replaceable?

Yes, but will cost about $135 per valve - the new part is cheap, the labor (machine shop) is not.
The old seat is drilled out completely, then the new seat is frozen in dry ice and force fit into the hole.
Then the new seat is reground to spec, taking great notice of the valve excursion.
 
Yeah that’s expected. No such thing as good and cheap when it comes to machining. I was mostly curious if it was difficult to find parts.

Not hard to find at all - Kibblewhite has them, of modern materials almost impervious to ethanol.
 
Great information, Thanks.

In Canada, Ethanol must represent a minimum of 5% of the content of all gasoline sold by volume. The way stations have been handling this is to put 10% ethanol in their regular gasoline, "up to 5%" in their mid-grade, and "May contain Ethanol" in their premium. This allows them to vary their ethanol compositions to meet the law, and reduce (but not necessarily eliminate) ethanol at higher grades... which would be fine, if they hadn't all gone to the one hose, three grades pump models.

I predict that the first liter (approximately a quart) of gas that I get in each fill up is 10% ethanol, but the rest is "probably" ethanol free (I use premium). I often take note of sports cars filling up and get in line behind them to reduce my ethanol consumption, but this is not easy and sometimes is awkward if there are three pumps available and I am waiting for the corvette to finish filling up!

Great post Nick, I'll have to try that additive!
 
Great information, Thanks.

In Canada, Ethanol must represent a minimum of 5% of the content of all gasoline sold by volume. The way stations have been handling this is to put 10% ethanol in their regular gasoline, "up to 5%" in their mid-grade, and "May contain Ethanol" in their premium. This allows them to vary their ethanol compositions to meet the law, and reduce (but not necessarily eliminate) ethanol at higher grades... which would be fine, if they hadn't all gone to the one hose, three grades pump models.

I predict that the first liter (approximately a quart) of gas that I get in each fill up is 10% ethanol, but the rest is "probably" ethanol free (I use premium). I often take note of sports cars filling up and get in line behind them to reduce my ethanol consumption, but this is not easy and sometimes is awkward if there are three pumps available and I am waiting for the corvette to finish filling up!

Great post Nick, I'll have to try that additive!

I used to have two stations with non-ethanol regular gas close to me but now there is only a Mobil. All of its grades are non-ethanol. It is great for all of the small engines as well as my 450 Nighthawk.
 
We have a weekly bike paper over here, Motorcycle News ( aka More C*** than News ), which often has 'helpful' articles, bike shop mechanics describing problems they've solved.

Last week, it was problems caused by water in the fuel. Solved by draining the tank, then dehydrating it by swilling out with methylated spirit (denatured alcohol).

Fine so far, until the final paragraph, where he stated that recurrence of problem could be avoided, by adding a small amount of meths to each fresh tank of fuel. I nearly emailed them, decided to wait and see if anyone else wrote in.
 
Thanks for that info. This past off-season I used Sta-bil (red) in the tank while the bike sat for a few months. Started right up when I decided to take my first ride of the season back in March. I also have been using a little Sta-bil 360 https://www.goldeagle.com/product/sta-bil-360-protection/ as an additive whenever I fill up. It was a flip-of-a-coin that i went with the Sta-bil 360 instead of Startron because i had read good things about both. Time to replenish my supply so I think I'll give the Startron a try.
 
Going for my first gas run on my bike (73 CL 350), couple clarifying questions (and I do not have any place reasonable to buy non-ethanol gas):

1) Stabil vs Star Tran differences? is Sta bil better for storage and Star Tron maybe better to use in regular use or no differences?

2) The previous owner was using VP non ethanol gas ($79 per 5 gal) - is it bad to switch back to gas and use one of the above additives?

3) What is the preferred octane using regular gas, 92 maybe ?

Thanks
 
On a stock 350 engine, 87 to 89 octane is fine and changing back from a high-end fuel (on which he way overspent for a stock engine - believe me I know, I don't even run anything like that in my 450 with 11.6:1 pistons) to a conventional fuel is no big deal either. There are varied opinions of Stabil vs Star Tron. I use Stabil, both in my power equipment fuel and my bike to help with the ethanol involved as I don't have non-ethanol fuel very near me either and it's a lot pricier as well as not high enough octane (just 89 mid grade) for my bike. I can't imagine you'd have any issues with either used in your regular to mid grade fuel, whichever you decide to run
 
I put an ounce of MMO in 5 gallons of 93 premium in my CB350, pretty sure the gas is an ethanol version. Comes out to about a 600:1 oil/gas mix ratio. I don't know if it helps, but I don't think it hurts.
 
Screen Shot 2020-08-14 at 9.25.47 PM.jpglooking in the CL 350 Manual for the size of the reserve tank, came across this specification on fuels. Like ancientdad basically said, it's a stock 350 engine from the 70's, why would Honda be recommending high octanes (95 or higher) in the original manual ?
 
View attachment 3654looking in the CL 350 Manual for the size of the reserve tank, came across this specification on fuels. Like ancientdad basically said, it's a stock 350 engine from the 70's, why would Honda be recommending high octanes (95 or higher) in the original manual ?

I saw the same thing and it made me scratch my head for a 9.5:1 compression ratio
 
There are 2 common methods of octane rating Research Octane Number, RON, and Motor Octane Number, MON. The pump fuel you buy is (RON+MON)/2. Canada uses the AKI, Anti Knock Index, and RdON, Road Octane Number, version like most of Europe.
RON is typically 8-12 points higher than MON.
All of the early Honda fuel requirements are using the RON version, some manuals leave off the RON when printed for some reason, probably because it was assumed the reader would automatically know since it was the only standard being used at the time.
 
Since I bought this bike last September I've been filling it with premium gas. I'm sure it's not hurting it, but I think the next fill-up I'm going to go with regular just to see if i notice a difference. After all, that's what the manual states. I'll still add my 1/2 ounce or whatever of Star Tron Enzyme Fuel Treatment Concentrate.

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All of the SOHC 400/450 models use regular 86 octane. Zero benefit from higher octane, I've tried. I can say the ethanol free did make the engine feel smoother under all operating conditions. Finding 86/87 octane ethanol free anywhere other than the Mid West is almost impossible.
 
Just as an aside, I put gas in my bike at a gas station for the first time today. Price of 2 gallons of gas really kind of put a smile on my face.
 
I've been using Stabil in the fuel I buy for all my bikes and power equipment and have had zero issues. I only have a couple of gas cans and as such, I buy 5 gallons of premium to keep on hand for my red 450 as the tank is only 1.8 gallons, meaning if it's on reserve when I get back from a ride - which happens often with only 1.4 before reserve - then I have to fill up at home before leaving since the closest station to me is over 7 miles away. So, my power equipment gets to enjoy premium fuel too, with a dash of Stabil in it.


Same here; I keep 5 gallons of Star-Brite treated premium gas In the garage for the CL350. I use the “as seen on tv” Turbo-Pump to effortlessly transfer the fuel- love that thing.
 
I've been using Tesco ( supermarket own brand ) Momentum 99 octane in my bikes, solely because I think ( EDIT: thought ) it has less ethanol than the regular 95 octane. I could be wrong, as I've recently had an issue with a rotted fuel hose on my CL175.

Also, Tesco is 'Pay at Pump', so no need to remove helmet, leave bike and go to cashier. In the UK, you have to take off your helmet if you pay at cashier, so that they can identify you on the CCTV. However, these days, you'd have to remove your helmet, then put a face mask on. Illogical.

I recently ran low on fuel on my CB 600, and ended up making a distress purchase of 95 octane fuel. If anything, it runs better on this, despite having a stock 12:1 compression ratio.
 
Just been on Google and found this:

"Tesco's 99RON Momentum is made by Greenergy.

It's not a bad fuel ie. it meets statutory minimum standards.

But, the octane rating is achieved by dosing it with up to 5% by volume bioethanol. Other than this amount of spirit alcohol it is the same stuff as Tesco's basic 95 RON unleaded. Alcohol is very astringent and drying and if you want to run your car on the stuff then best to buy one that's designed to run on it. "

Guess I won't be using that again.
 
Interesting. My cousin worked for 3 big oil companies over a 40 year career of driving tanker trucks delivering fuel to stations around the central Florida area, and when the ethanol thing started here he told me the same thing about it. It actually helps them make more money, since it raises the octane rating so they actually sell less gallons of premium while still meeting the octane rating of premium and keeping the per gallon price the same. Clearly an idea cooked up to sound good for the environment but actually increasing profits for big oil. I just read that it takes 26 lbs of corn to produce 1 gallon of ethanol (Cornell University study). And, one study says burning ethanol in fuel increases the CO2 output which adds to the greenhouse gas levels, but there seem to be many conflicting studies shown about that.
 
If you are near an airport (even a small one) you can typically get Avgas which is non-ethanol and has high octane also (100+)
Avgas also has high lead content which is beneficial to our engines.

https://www.airnav.com/fuel/local.html


You'll want 100LL and not Jet A.
My son runs it in his SuperMoto CRFs with higher compression pistons.

Works well.
 
I guess I'm just a cranky old man, "hey, get off my...," but I don't know why people include gifs in their posts. Am I supposed to read the post, or watch at the gif? Like music on youtube videos, while someone is talking about how to overhaul a Keihin 723 carb. Anyway, if you're using firefox and want to turn off gifs-


  • Type "about:config" in the address bar.
  • Click "I accept the risk!" when it comes up.
  • Find "image.animation" using the search box (just type "anim")
  • Double-click "image. animation_mode."
  • In the next box, type either "once," so the animated GIFs only get one chance to play, or "none" so they never can.


(Thanks, google)

And by the way, thank you Nick_Brox for an very informative post. I'll be using non-ethanol fuel in the bike when I get it on the road. Fortunately, there's some about two miles away.


Cheers
 
Our problems with ethanol are far worse than what's been brought up so far.
The stuff is death to our valves and valve seats, they get decayed like bad teeth after a while.
Now seats can be reground of course, but on one beloved model (CB/CL450 DOHC) this often times leads to worse issues of valve extrusion.
At least 50% of the 450's I've seen have (probably) ethanol related damage in this way.

Most problems with Ethanol are due to not riding the bike regularly and avoiding costs to adept the bike to new fuels. If you want to ride these bikes, change the rubbers and gaskets in your carbs with ethanol resistant rubber and replace the valve seats for Ethanol resistant ones.

Problems solved.

I added over 20.000 km's on my bomber after rebuild including replacing the seats and valves, no issue's with Ethanol (10-15 %). We are not allowed to ride the bike in winter, so I add a stabilizer before parking the bike with a full gas tank to avoid rust.

It's almost impossible to get ethanol free patrol in the Netherlands, and I think that now the US signed the Paris Climate Agreement, it won't be long that the US faces the same situation under the flag of environment and sustainability (and this is not a political statement, just an observation).
 
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Problem is that replacing valve seats will cost around $135-$150 per valve - if you can find a machinist willing to do it......
 
Replacing mine costed me 100 euro per valve, not that expensive taking into account that you upgrade your bike and make it withstand modern gas. It also depends what your intention was for buying a bike this age. If people thought it was a cheap ride, they're wrong. Riding a classic bike as being a modern bike will cost you. Buying them cheap doesn't mean you don't have to spend money.

For some reason people think that parts and work on a classic bike should be cheap because the bike is old (nice if possible !), but the reality is different. Look at the prices of parts of modern bikes, if someone thinks that 800 euro is expensive for a set of NOS mufflers of a 450, take a look at a modern muffler system of any given Japanese bike today.
 
I am far, far from even a novice on this subject. Carburetors and I generally speaking, do not have good relationships. It is a subject I've gone back on forth on though, mostly due to the doom and gloom predictions that seems to follow it. Always with boo coos of "personal experiences" attached to each story. I'm not doubting ANY of that. I'm not suggesting that anyone else should, but... here's another view. Offered simply to show there IS another view. You'll have to be the judge. Me? I STILL haven't decided if it's the worst things that ever happened to gas, or something else. What I do know is that usually, it's the only thing available today. :eek:

https://motorcycleproject.com/

Scroll to near the bottom under the "Tech Articles" heading, then scroll to "Ethanol good or bad?"
 
Hey, is ok to go back-n-forth from VP Vintage Fuel then to 100LL Jet fuel then back or mixing when going from one to the other? Thanks
 
100LL is aviation gasoline, not jet fuel (that would not work). Not aware of problems with high octane causing damage but it provides no benefit either if your engine doesn't require it. The lead content could be beneficial in bikes older than mid 70s, someone may have experience with lead in newer bikes.
 
Not sure why you would run 100+ octane fuel in an engine designed for 86. But there shouldn't be a problem other than a light wallet.

Not doing it for the 100 octane, but rather the no ethanol. I know folks on this string earlier said to just use regular gas plus Stabil. I was certainly going that way. Then I worked out all of my carb issues that drove me crazy for the past year. I finally replaced the carbs and now the bike runs great. The mechanic I worked with and some others swear by the VP Vintage fuel stuff. But Geez that stuff is crazy high (~$93 / 5 gal drum). @76Twin said on page 1 of this string that 100LL AV is a good option. I live really close to a small airport and the gas is only a $1/gal more than car gas. Others have suggested this plane fuel too in other groups and local friends. I think I am moving that direction. It's hobby gas, not commuting gas, so I guess I am okay with the cost for now.

I have to re-read all the other responses and maybe it's already been commented on but is ok both 100LL and VP vintage get sloshed together in the tank at the same time? Or do I need to burn one all the way down before mixing in the other? Thanks
 
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