Rethinking fuel.......

I believe all the air cooled XJs specify gasoline with a Research Octane of 91. That is roughly equivalent to 86 Pump Octane, which is the measure used in North America. So I've recommended a number of times that common unleaded at 87 Pump Octane is just fine for the XJs.

This winter I purchased a Stihl chain saw. While it's rated for 87 octane, they have warnings everywhere that if the fuel has ethanol (10% max) that 89 octane be used because the ethanol burns hotter. The higher octane fuel burns cooler. They repeatedly warn that 87 octane fuel with ethanol may reduce engine life because of the higher heat.

In the U.S. almost all gasoline is 10% ethanol unless it is purchased from an airport or possibly a marina.

While the air cooled XJs aren't 2 cycle they are air cooled. I'm wondering if a bit higher octane might be prudent in them.

Food for thought.

 

It's odd that Sthil would say that ethanol belnded fuel burns hotter. It dosen't. Ethanol increaes the octaine rating of whatever fuel it's blended with. Just chose your fuel based on the appropriate octaine rating and don't worry about it. Remember, our machines were built during the era of Gasahol, what we now call E-10.

Have a gander at a short FAQ about ethanol blended fuel:
http://www.carsonoil.com/proBioAboutEthFAQ.asp?pageid=prod&subid=prod63

Please note that I to take issue with their reply about using crops for fuel, but on the purely technical questions their answers are accurate.

 

K-moe that link you provided WILL destroy people's motorcycles. Ethanol is nothing but garbage plain and simple. Carson oil are bold face liars. There's a place in Dover, Pa that has a picture of a upside down lawnmower. A sign above it states this is your mower on ethanol. Dead. I compaire ethanol to what happened when you couldn't purchase leaded fuel anymore. You had to tear the top end of the motor apart to put hardened valve seats in. If I can figure how to do it I will scan a article in from February 2011 of Popular Mechanics about that garbage ethanol and what it does to your vehicle.

 

It's tougher on the seals in the carbs and results in lower MPH. Oh and it collects water so you get green crap on your emulation tubes if you let it sit in the system any length of time but other than that it's wonderful stuff. Corn is for cows not motors.

 

Sorry, but no. I've used E-10 for 30 years in all my vehicles, and power equipment, and had no troubles at all. The only issue with ethanol is not upgrading the rubber parts if your US market vehicle was made prior to 1981. The issues that people are attributing to ethanol blended fuels are the result of improper maintenance and storage.

 

Here's a fun fact......non-ethanol gasoline collects water too. So called "straight" gas (it isn't) can absorb less atmospheric moisture than an ethanol blended fuel can, and that's not a good thing. Once the fuel reaches it's saturation point the water drops out of solution, and THAT is when water begins to cause trouble. Much of the moisture trouble that I see isn't from the fuel absorbing atmospheric moisture; it's from condensation in a partially filled tank during long-term storage. Whether E-0 or E-10, gasoline cannot absorb liquid water very well, so the condensate drops to the bottom and corrodes the tank. The same process occurs in float bowls.

I'm not going to debate. If you want to believe the myths about the "evil" ethanol then you can. Heck, statistically 1/4 of you still believe that the sun revolves around the earth. http://blogs.discovermagazine.com/imageo/2014/02/17/1-in-4-americans-believe-sun-revolves-around-the-earth/#.UwkZoHm8cZY

 

Sorry K-Moe I disagree with you and I don't know where MiCarl got his info from.... I can get non ethanol fuel at a couple of places in my small town. This is the only thing I will use because I know for a fact that ethanol fuel will varnish up your carbs. Oh, and as for as the chainsaw goes.... I learned first hand that ethanol fuel ate right through the fuel line on my Stihl chain saw so I will only use non ethanol in my chainsaw and leaf blower etc. as well. Ethanol fuel is crap and anyone that says different doesn't know what they are talking about.

 

i'am about to find out what e10 does to my carbs they're on the bench now and haven't been opened for 3 maybe 4 years, so we'll see.

 

OldBikerDude,

Carbs were varnishing long before E-10 was widely available. Do a little experiment. Put some white grain alcohol in a glass and let it evaporate. Look to see how much varnish is left behind. Look reeeeealy closely; you won't find any. The varnishing you see in a carb is the remains of the petrochemicals that have evaporated away.

As for the fuel line on your chainsaw; that was a CHOICE that Sthil made. They chose to ues a fuel line that isn't ethanol compatible, because it's a less expensive part.
Pennies saved x high production volume= millions in profits.

 

Sorry K-Moe still don't agree with you on this one. When I used ethanol fuel I had to clean my carbs every year. For the last 3 years I have used the better Non ethanol fuel and I haven't had to clean my carbs at all. Same bike nothing changed but the fuel. It just stands to reason that it was the ethanol. Oh and I ride my bike year round so it isn't from sitting any length of time. Hey, if you want to put that junk in your bike be my guest. I am not going to.

 

been at least three years since these were opened. whatever mid grade gas was handy

 

E10 will hold water in solution better than pure gasoline. That allows the water to get into places it did not get to before. Before the addition of ethanol the water would collect in the sumps and low points of the fuel system now it just rides along with the fuel. That's what dry gas additive was for back in the day. And did you ever go to a race were the engines were being run on pure ethanol? Ever notice that they always run them post competition on pure gasoline to get the ethanol out of the fuel system cause its corrosive? If you have stainless steel components as they do now it will not matter, we have brass jets and tubes which don't stand up to it very well. It's your engine k-moe run it on whatever you want.

 

Wow! I kicked off a firestorm.

The reason for my claim that most gasoline contains ethanol is because mandates are forcing fuel blenders to use a quota of ethanol. To meet the requirements they have to put it in almost everything.

My understanding is that the FAA will not allow ethanol in aviation fuel. So, if you buy aviation gasoline it should be ethanol free. Because ethanol is such an issue in a marine environment I understand that often times marinas also have "pure" gasoline.

In my experience running the 10% ethanol is not an issue for most carburetor systems, provided it doesn't sit there for long. Untreated ethanol blended fuel seems to lead to snot-like deposits and corrosion of the brass in pretty short order.

Occasionally I'll get a carburetor that has been in a barn for 30 years. It'll have varnish on everything but not the corrosion I see with modern fuel.

************

But back to the original point - Stihl's claim that ethanol blended fuel burns hotter. That surprised me too, because I've been under the impression that ethanol did burn cooler.

Yes, ethanol is higher octane than gasoline and is a cheap way to boost octane. That's why I've always been skeptical of claims that high octane gasoline is less likely to contain ethanol.

As I write this I'm wondering if adding the ethanol lets them get away with using poorer grade gasoline for a given octane rating. In other words, 87 octane fuel is something else (suppose 80 octane) that is boosted by the addition of ethanol. That underlying low octane gasoline may be the cause of the extra heat.......

 

So, I guess I'll jump in here, too...........

all my bikes use 87 octane gas from the pump. The pumps around here sell 93 octane w/o ethanol. I don't use that. I occasionally will throw some seafoam in, but not regularly.

I do the same thing with my sleds.

I do the same with my chainsaw..........it is a mcculloch and STILL has the same carb kit in it that was in it when I bought it 21 years ago. I may use it several times a year, I may not start it for two years.....But, it always starts up and runs fine.

My PERSONAL opinion is that it is not the gas that is the issue.....it is the NEGLECT that is the issue. The sleds that I see with green carbs, the bikes that I see with green carbs, the equipment that I see with green carbs-------the ONE thing they have all had in common so far, is that they have all been left out in the lawn where rain can runin through the vents, key holes, etc....... and allow water to pool. THAT has been the problem with carbs I've had to do for people.

The sleds sit out in the lawn all year long, BUT I put a cover over the gas cap. I have YET to find a varnishy set of carbs on any of the bikes, sleds, etc........ I probably will, now that I have typed this all out, but I can be pretty sure it will be because of something I missed.

Last, a motorsports shop down the road did something neat--they keep a jar of nasty needles, jets, and seats on their counter. Now up on the shelf they have a series of jars with a needle jet in each one. One jar has just plain gas in it each of the others have gas with various additives in it.....one has sta-bil, one has marine sta-bil, one has-- etc... etc... etc.....

After two years, they took them down and I asked to see the differences between them and the plain gas one. They said they took them down because nothing had changed. Hmmm....................

FWIW.............. fire on-----

dave

 

You may want to call around to your gas stations and ask if they sell non ethanol fuel. There are 2 places in my town that sell it. It is sold as a Premium gas at both places. It is much higher octaine than the regular. It does cost about .40 cents more per gallon but it is worth it to me.

 

They were missing outside temp swings, moisture condensation, and evaporation of the lighter elements in the fuel. Sealed jars !!

The formation of Glycerin - the additional Oxygen causes the "green goo"

You can store a rifle 100 years coated in "cosmoline". It's the Oxygen. And Gasohol is an Oxygenated fuel.

 

I told them that, too, but they said "it doesn't matter....it picks it up from the air". Just relating the incident, that's all.

Now here's another thing-- two years ago I picked up a sled that had a problem, so I got it cheap. Here's what the PO told me----

"It runs fine as long as we stay on the flat part of the lawn, but any time the kids run down over the bank, it stalls and I can't get it to start. I'm tired of taking the tractor down to pull it up. After it sits a day or two, I can get it to start........and hope they don't run down over the bank with it"

SOOOOO.......I bought it, brought it home, drained the gas tank into clear gallon jugs. 3 1/2 jugs full of the cloudiest gas I have ever seen.....Water in the gas. I set the jugs on the shop floor to just sit for awhile. I pulled the carbs, they were clean but one emulsion tube top shroud was buggered up so I replaced that with an ebay find (unique to that carb, of course). Carbs were ok, but I cleaned them anyway.

I pulled, cleaned, and dried the tank. Put fresh gas in it and have ridden it since, without any incident. Oh, he had a short pick=up line in the tank--it was not long enough to reach the bottom, nor did it have a weight on it. It was also to short to 'float'....it was just a few-inches-long stub. Problem was, on the lawn, the stub stuck into the gas but when they'd go over the bank the water level would surge forward and get sucked into the line. Doh.

Anyway.......back to the gas. After a couple weeks of sitting in the jugs on the floor, the gas was clear on top, and the water was at the bottoms. Gas smelled perfectly fine. So, I decanted that off the top, used it in the sleds, and what didn't get used up, got used in the tractor when summer came.

The amount of water? Slightly over a gallon and a half. My bigger question has always been----how the heck did he ever end up with a gallon and a half of water in his gas tank!?!?!?!

Anyway........thought you'd appreciate that.......................

dave

Dave

 

temperature cycling. simply stated, when the sun comes up and the day warms. the air inside the tank expands and vents out of the tank. when the sun goes down and the temperature drops, the tank draws in the humid air, whereupon the moisture in said air condenses. lather, rinse, repeat on a daily basis.

CN

 

A friend's Subaru didn't run, and I helped him. We found 5 gallons of water in the tank !! Sabotage !

 

There's a reason why airplanes have multiple fuel drains, and why conscientious pilots check them before every flight. If the consequences of contaminated fuel in ground vehicles were more serious there would be an easy way to check for contamination in them too.