Or~

Octane: A unit of measurement describing a fuel's burn speed.

 

Ethanol is bad and Ethanol above 10% is very bad.

I have been running 87 octane in my Harleys for years without the slightest hint of a knock or any detrimental symptoms. I do sometimes use 91 if I am at an event (Daytona Bike Week/Biktoberfest for example) where there's traffic and it can get hot. Modern ECM controlled engines adjust timing to avoid pre-ignition/detonation.

All other things being equal, lower octane will provide more power per pound of fuel. That's right, lower octane provides more power per pound of fuel despite the common misconception to the contrary. Octane is a fuel's resistance to combustion; the higher the octane rating - the more resistant to combustion it is.

"Why then do racing engines use high octane racing fuel?" is a question often asks in the course of this discussion. The answer is because those specialized application engines are running high compression and sometimes induction pressurization (boost from a turbocharger and/or supercharger); these factors increase the likelihood of pre-ignition/detonation. The higher octane, which allows for more compression and induction pressurization provides more power than more normal compression ratios that we use and natural aspiration. IOW, racing engines get more power out of higher octane because of other (mechanical) factors.

One of my cages recommends 91 octane, been running 87 in it for years. My Harleys, for decades, barely know anything else other than 87.

All that being said, the manufacturer's recommendations should be followed if that gives you peace of mind. Then again, that very same Owner's Manual has recommendations for breaking in a new engine which, to anyone who knows anything about internal combustion engines knows, doesn't help seat the rings properly and actually can promote cylinder glazing. The Owner's manual also "recommends" Harley Davidson branded things like tires and oil ... neither of which Harley makes. Just sayin' ...

I have run 87 octane, used lubricants other than Syn-3 and rolled Avon tires for years; my bikes seem very happy and none of my manly goins-ons have fallen off! One of these days I'm going to get the courage to rip the Federal Warning tag off my pillow.

 

EPA can say anything they want - they will not pay for warranty.

Ehtanol is a sorry attempt at improving emmissions, which it does not do. It results in the fuel being more hydroscopic. Although it may slightly increase octane, it has less energy - a gallon of ethanol contains only 75% of the energy of a gallon of gasoline) - this is the same drop in fuel economy that you will experiance. In addition, alcohol dries out most rubbers and is corrosive. Fuel fittings not rust out, fuel lines crack more readily, etc. Sure they improved the fuel systems to tolerate ethanol, but it is still not a good thing.

Thanks EPA! Now they are working hard to F'up diesels so they are leaving gasoline engines alone!

 

You beat me to it.

One final point, if it is so great, why do all marina's sell (with the Gubmint blessing) ethanol free fuel? In gas stations on the coast or by the great lakes, you can get ethanol free fuel cheap. Move inland and ethanol free fuel is twice as expensive - it is treated like racing fuel.

 

FWIW, the manual says nothing about ethanol so I stay away from it. I try to get as close to the recommended octane as possible.

Rarely ever get stuck having to use ethanol.

 

The ethanol took out my fuel lines on my scoot last week. 11 Limited.
The quick connect on the gas tank was gushing when I pulled over. Limped it to a Harley shop (I was traveling at the time) the shop had one of the two lines at the time so I had to hitch a ride 60 miles to another dealer to get the hose that goes in the tank.
Cost me a day on the road and a few hundred bucks all because of ethanol. Ethanol sucks

 

Look harder. I suspect it does.

I try to avoid it, but little choice unless I want to use gas cans. My small motors I use gas cans, mower, atv, snowmobile, saws. Though when I traveled farther distances on sled, I had no choice. 4 stroke sled makes it easier.


I think the key to ehanoel is not letting it sit for months. I make sure when I park bikes for winter corn free. But I think some years it has happened. You keep turning the gas over, you should not have a problem with 10%. Granted when I can, I avoid it.

 

A limited amount of Chevrons, at least in Arizona, have it in 5 gallon cans, not at the pump. For you guys that bed down your bike for the winter it would probably be wise to run out your ethanol by buying a can and refilling at home for your last weekend ride.

I don't concern myself with ethanol too much, I ride all year, but I do take notice of ethanol free pumps and use them when I can, for all my vehicles. It's easy to remove if you have a need.

 

Huh? You buy gas already in a gas can? I just bring a red can to the station and fill it up at the pump. Not for my bike. I ride to much to to fill my bike up with a gas can. Not a fan of corn but I have ran lots of it. As long as you turn it over you are fine. Storage is the issue.

I never run corn free in my trucks. Used to be premium was only .20 cents or so but not I think it is 50-75. I drive a lot, so it doesn't sit

 

Well I'm going to be odd man out here. I buy fuel, be it 85, 87, 89, ,91, 93, non ethanol, 10%ethanol. I don't buy e85, I don't buy if it's more than 10% ethanol.

In some spots I've been in you pump what they sell and be happy you have fuel.

A lot of people will say, it's bad for the bike. Yup I agree it is if you hammer the **** out of it with 85 octane in the tank.

If you are stuck and have to pump 85, then ease up, adjust your riding style till you can get 91 or better fuel. The bike will run on 85 and better but you cannot race your friend and call it good.

I've been in some very rural places at 2am pumping fuel and you take what you can get. By the way, this with a 120R, warmed over with 11 to 1 and .650 high lift cams.

Don't get stuck looking for fuel in unknown places, yeah I agree with that as well. But sometimes it happens. Make your own choices.