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Discussion Starter #1
I'm getting conflicting information as to what kind of gas to put in my new Street 750.

The dealer told me to always put in premium, however the manual states "87 (91 RON)" which would be standard gasoline. The HD website however says "Recommended 91 octane or higher fuel (R+M)/2." (See Street 750 | Liquid-Cooled | Harley-Davidson USA )

So what is the appropriate fuel for my new Street 750?
 

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Either or. Recommended just meand optimal performance but you wont get the pings. You'll be fine with 87 don't worry. Now many do run 91 just because its a smaller tank, better MPG's. Its up to you...
 

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I'm getting conflicting information as to what kind of gas to put in my new Street 750.

The dealer told me to always put in premium, however the manual states "87 (91 RON)" which would be standard gasoline. The HD website however says "Recommended 91 octane or higher fuel (R+M)/2." (See Street 750 | Liquid-Cooled | Harley-Davidson USA )

So what is the appropriate fuel for my new Street 750?
That's a good question, when I was at the dealer I told them I only burn premium gas in all my motorcycles. In fact I only burn premium gas in my lawnmower, weed whips and leaf blowers too. Most premiums here (Chicago land) have additives in them to help clean fuel injectors which the streets are fuel injected. So therefore, I'll stick with the premium gas and pay the few extra cents more.:D
 

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The 750 is 10:1 compression, and the 500 is 11:1 compression.
I suggest the highest octane available.
 
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The octane debate.

Premium does not really mean anything better.

Octane is representative of the level at which the gasoline will ignite under pressure with no spark. Commonly called pre-ignition. No octane level is better than any other from a gasoline quality standard. So octane has to do with the engine compression and the altitude you live and drive at. I run 87 in all 4 of my bikes. Vrod to the buell.

I live at 5000 asl so no chance of pre-ignition with that octane here.

The 750 at sea level will not pre-ignite with 87.

Won't hurt anything but your wallet to run 91 but in many cases it is not necessary.

Just don't use 91 because it is said to be premium. It is actually worse than lower octane since they add alcohol to change the ignition pressure.
 
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The octane debate.

Premium does not really mean anything better.

Octane is representative of the level at which the gasoline will ignite under pressure with no spark. Commonly called pre-ignition. No octane level is better than any other from a gasoline quality standard. So octane has to do with the engine compression and the altitude you live and drive at. I run 87 in all 4 of my bikes. Vrod to the buell.

I live at 5000 asl so no chance of pre-ignition with that octane here.

The 750 at sea level will not pre-ignite with 87.

"Won't hurt anything"but your wallet to run 91 but in many cases it is not necessary.

Just don't use 91 because it is said to be premium. It is actually worse than lower octane since they add alcohol to change the ignition pressure.
A very good point that you bring up, but companies like Mercedes-Benz recommends that you only burn premium in their automobiles if you do not, you void the warranty on the engine. In fact, right in the instruction manual it will say if you have to put anything except premium in the car only put as much gas in the car to get you to the next gas station to fill up with premium only.

With that said, there must be something premium does that the other two octanes don't do, that Mercedes-Benz feels that you will destroyed their engines if you don't use it, It voids out the warranty! Food for thought.:rolleyes:
 

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A very good point that you bring up, but companies like Mercedes-Benz recommends that you only burn premium in their automobiles if you do not, you void the warranty on the engine. In fact, right in the instruction manual it will say if you have to put anything except premium in the car only put as much gas in the car to get you to the next gas station to fill up with premium only.



With that said, there must be something premium does that the other two octanes don't do, that Mercedes-Benz feels that you will destroyed their engines if you don't use it, It voids out the warranty! Food for thought.:rolleyes:

Pre-ignition pressure is important. And high performance high compression require it.

But the label premium is just to get people to think it is better or more powerful. Neither of which it true.
 

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Both my Sporty and my Street Rod supposedly require minimum 91 octane according to the manual. There is about $.35+ difference here between 87 and 91. However, the other benefit of running 91 is that where I buy gas, 91 is non-ethanol, whereas the 87 and 89 are 10% ethanol. Now I don't know if there would be any negative effects of running ethanol gas in my bikes, but it does wreak havoc in small engine equipment such as mowers, chain saws, etc.. Cars made these days do not seem to be affected if driven daily, but my old classics are another story since they are stored over the winter. Ethanol gas and long term storage do not complement one another for sure.

Enough rambling... if it were me, I would use 91, preferrably non-ethanol if available.
 

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As per the HD Owner's Manual....for years....it has stated to use a minimum Octane Rating of at least 91. This is due to HD using a med/hi compression ratio and that the engine is air cooled, the higher Octane Rating will decrease pinging, also, especially critical on the newer fuel injected bikes like the Street 500 & 750, Premium Gasoline contains additives that lower grade gasoline doesn't have that help keep the injectors and fuel filter clean.

The information listed above is from one of Harley Davison’s mechanical engineers that I talked to. So, for the extra $1.40 more for a tank of gas in the Street: Is it really worth to cheap out? Stay with what is recommended by the manufacturer and you’ll be safe.
 

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Discussion Starter #10 (Edited)
I wouldn't say I'm trying to cheap out, I just want to make sure I'm buying the correct octane for the bike. In theory, using higher octane that recommended is actually causing your engine to produce less power and use more gas.

My car requires 91 octane by the manufacture. The problem is the conflicting information given by Harley. The manual given with my bike states 87 octane, the website 91 octane, and the dealer 91 octane. If it really is 91 octane they should update the US manual.

For now I've just been using 91. The bike has been running fine and just hit 175 miles (Not bad for a week of ownership.) I'm glad to hear that a HD mechanical engineer recommends 91, it puts my mind at ease.
 

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As per the HD Owner's Manual....for years....it has stated to use a minimum Octane Rating of at least 91. This is due to HD using a med/hi compression ratio and that the engine is air cooled, the higher Octane Rating will decrease pinging, also, especially critical on the newer fuel injected bikes like the Street 500 & 750, Premium Gasoline contains additives that lower grade gasoline doesn't have that help keep the injectors and fuel filter clean.

The information listed above is from one of Harley Davison’s mechanical engineers that I talked to. So, for the extra $1.40 more for a tank of gas in the Street: Is it really worth to cheap out? Stay with what is recommended by the manufacturer and you’ll be safe.
I never look to the owners manual to tell me about gasolines. I look to the owners manual to tell me about what is recommended at SEALEVEL for octane.

I do care about what Gasolines I am running in my bikes. And since HD does not make gasoline I look to the Gasoline companies for guidance....

CONOCO:

Being a good car owner just got a lot easier, as our gas now has 3 times more detergent additive than the minimum required by the EPA. Not only that, it also has 30% more than the minimum level specified in the TOP TIER® Detergent Gasoline standard recommended by major car manufacturers.* Every drop has been carefully designed with just the right amount of engine-cleaning power to avoid the side effects that can be caused by overtreating. It's everything a trusty companion like your car deserves.


I am not posting to convert, I just want the information out there that "PREMIUM" is a marketing ploy, the gasoline's octane level has not one thing to do with quality... Premium is used to make people believe they are getting something better... they are not... because of the prevalence of injectors now all quality gasolines are detergent and all from a single manufacturer contain the same amount of detergent.

As for the $1.40 per tank... again do what you want... but I ride 35,000 miles per year. That is 921 gallons of fuel... that .32 cents is $294 dollars... that is the second set of tires I need during the year..... I understand if you ride 2K to 5K you may forgo the $42 it will yield.

But if you understand Octane and its requirements and use and how altitude affects the systems, you can save some bucks.

Free warranty hint...... something does go wrong... fill the **** thing up with 91 before you take it in and practice the "I know nothing" speech.....

Do what the book says... but for those that can understand the science... educate yourself and save...

Should point out if the engine is turbocharged or super charged you must stay with the higher octane and the air pressure devices make up for the 2 PSI in atmospheric reduction at 5000 ASL.
 
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I wouldn't say I'm trying to cheap out, I just want to make sure I'm buying the correct octane for the bike. In theory, using higher octane that recommended is actually causing your engine to produce less power and use more gas.

My car requires 91 octane by the manufacture. The problem is the conflicting information given by Harley. The manual given with my bike states 97 octane, the website 91 octane, and the dealer 91 octane. If it really is 91 octane they should update the US manual.

For now I've just been using 91. The bike has been running fine and just hit 175 miles (Not bad for a week of ownership.) I'm glad to hear that a HD mechanical engineer recommends 91, it puts my mind at ease.
Saw this thread and found it interesting. So, I called H-D Tech Service and discussed the conflicting information with them. Received email this morning: "87 or higher for fuel rating."
 

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For those interested this is a link to the pressure changes I am speaking of......

Air - Altitude, Density and Specific Volume

For my altitude this calculates to a 15 percent reduction (derating) in Horsepower. Make it hot at this altitude (been in the 100 F range) and it gets way worse.
 

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I don't see much of a reason to worry about getting premium fuel for your Street. It's not like this is a racing engine or anything. I say, save your money.
 

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Well theres no reason to worry NOW. But before when it was unclear there was every reason to be leery, early detonation can cause a whole host of problems for the engine internals...
 

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Okay, I’m a synthetic microbiologist that depends on scientific facts not placebo science like Lysenko did. Anecdotal information is not science, but only what one thinks and/or accounts as science as truth without scientific facts to back up theories and no accountability for their actions.

Quote: Do what the book says... but for those that can understand the science... educate yourself and save...

Please inform all of us of the scientific facts you’re talking about and the test that were conducted to prove what you say is factual and not some anecdotal account? After all you brought up about the science so please enlighten us and give us your references please. So we all can be educated ourselves as well as you are. Only scientific facts and testing please.

Quote: Free warranty hint...... something does go wrong... fill the **** thing up with 91 before you take it in and practice the "I know nothing" speech.....

So now you’re admitting your own doubtfulness on this subject with this quote and you what all of us to… lie? Did you know there are some younger forum members that could be reading this and now you just told them to lie and cheat their way into life! I’m I understanding this correctly?

If there is any scientific fact, and if Harley-Davidsons’ engineers don’t have an inkling what they are talking about, have you then tried to educate them on this subject? Are you a metallurgist or a quantum mechanical physics professor on the combustible engine? Did you ever think that HD is covering all bases with all people no matter were their geographical location is are the topography of their landscape above or below sea level when they say use premium gas…well they are and Victory Motorcycles does the same thing. For the few pennies you’re saving it’s not worth the trouble to not do what the owner manual says. So maybe you’ll have to forgo that Café Latte at Starbucks and just get the cream and sugar instead.

Quote: I am not posting to convert, I just want the information out there that "PREMIUM" is a marketing ploy; the gasoline's octane level has not one thing to do with quality... Premium is used to make people believe they are getting something better... they are not... because of the prevalence of injectors now all quality gasolines are detergent and all from a single manufacturer contain the same amount of detergent.

Okay, so now premium gas is “Dr.Oz’s” newest placebo that’s being sold under false pretenses for all these years? We’ve been bamboozled into believing that we’ve done something good, when all along we have done nothing for the betterment of our combustible engines? The petroleum companies are not only polluting our oceans but our minds too! The inhumanity of it all! So when BP cleans their premium gas to a micron filter clear state instead of that Carmel color that’s all just a ploy?

By the way: Is anything that is said above in this quote, has to do with that “science” you were talking about? Do you really think people on this forum have the education of a June bug?


Quote: I never look to the owners manual to tell me about gasolines. I look to the owners manual to tell me about what is recommended at SEALEVEL for octane.

I do care about what Gasolines I am running in my bikes. And since HD does not make gasoline I look to the Gasoline companies for guidance....


Really! You never look at the owners’ manual for petro suggestions? Then I suggest you stay away from BMW’s, Mercedes-Benz, Jaguars, Porsche’s, or any other high-end automobile because all their owner manuals say what kind of gas to use and if you don’t …then your warrantees is void! Also, not one of these companies make gas for their own automobiles, but they do have the MIT engineers that designed those engines in those cars tell them what to use in their cars for best performance. But I’m sure those MIT grads know that premium gas is only a placebo so why recommend it in the first place…right!

Do you really think the HD engineers are standing around with a piece of straw hanging out of their mouths and barefoot and saying Heehaw and they don’t have a clue what they’re talking about? Give me a break!
 

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Harleys are old & antiquated Push-Rod bikes with low compression ratio. They don't require high octane numbers to run. Fill the Tank with Kerosene and still they would run fine.
 

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Discussion Starter #18
Saw this thread and found it interesting. So, I called H-D Tech Service and discussed the conflicting information with them. Received email this morning: "87 or higher for fuel rating."
Well at least that matches the owners manual. I figured it was more likely the manual to be correct than the website. Most of the dealers around here haven't even seen a street yet.
 

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Harleys are old & antiquated Push-Rod bikes with low compression ratio. They don't require high octane numbers to run. Fill the Tank with Kerosene and still they would run fine.
The Streets are different... We've been through this... wheres DT!!!???

No more potatoes...
 

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Okay, I’m a synthetic microbiologist that depends on scientific facts not placebo science like Lysenko did. Anecdotal information is not science, but only what one thinks and/or accounts as science as truth without scientific facts to back up theories and no accountability for their actions.

Quote: Do what the book says... but for those that can understand the science... educate yourself and save...

Please inform all of us of the scientific facts you’re talking about and the test that were conducted to prove what you say is factual and not some anecdotal account? After all you brought up about the science so please enlighten us and give us your references please. So we all can be educated ourselves as well as you are. Only scientific facts and testing please.

Quote: Free warranty hint...... something does go wrong... fill the **** thing up with 91 before you take it in and practice the "I know nothing" speech.....

So now you’re admitting your own doubtfulness on this subject with this quote and you what all of us to… lie? Did you know there are some younger forum members that could be reading this and now you just told them to lie and cheat their way into life! I’m I understanding this correctly?

If there is any scientific fact, and if Harley-Davidsons’ engineers don’t have an inkling what they are talking about, have you then tried to educate them on this subject? Are you a metallurgist or a quantum mechanical physics professor on the combustible engine? Did you ever think that HD is covering all bases with all people no matter were their geographical location is are the topography of their landscape above or below sea level when they say use premium gas…well they are and Victory Motorcycles does the same thing. For the few pennies you’re saving it’s not worth the trouble to not do what the owner manual says. So maybe you’ll have to forgo that Café Latte at Starbucks and just get the cream and sugar instead.

Quote: I am not posting to convert, I just want the information out there that "PREMIUM" is a marketing ploy; the gasoline's octane level has not one thing to do with quality... Premium is used to make people believe they are getting something better... they are not... because of the prevalence of injectors now all quality gasolines are detergent and all from a single manufacturer contain the same amount of detergent.

Okay, so now premium gas is “Dr.Oz’s” newest placebo that’s being sold under false pretenses for all these years? We’ve been bamboozled into believing that we’ve done something good, when all along we have done nothing for the betterment of our combustible engines? The petroleum companies are not only polluting our oceans but our minds too! The inhumanity of it all! So when BP cleans their premium gas to a micron filter clear state instead of that Carmel color that’s all just a ploy?

By the way: Is anything that is said above in this quote, has to do with that “science” you were talking about? Do you really think people on this forum have the education of a June bug?


Quote: I never look to the owners manual to tell me about gasolines. I look to the owners manual to tell me about what is recommended at SEALEVEL for octane.

I do care about what Gasolines I am running in my bikes. And since HD does not make gasoline I look to the Gasoline companies for guidance....


Really! You never look at the owners’ manual for petro suggestions? Then I suggest you stay away from BMW’s, Mercedes-Benz, Jaguars, Porsche’s, or any other high-end automobile because all their owner manuals say what kind of gas to use and if you don’t …then your warrantees is void! Also, not one of these companies make gas for their own automobiles, but they do have the MIT engineers that designed those engines in those cars tell them what to use in their cars for best performance. But I’m sure those MIT grads know that premium gas is only a placebo so why recommend it in the first place…right!

Do you really think the HD engineers are standing around with a piece of straw hanging out of their mouths and barefoot and saying Heehaw and they don’t have a clue what they’re talking about? Give me a break!
We appreciate the articulated elucidation but the persiflage is a bit much ;)

To start off I want to say Science is only the proof, there can be no science without a theory that needs to be proven. I'm sure that itchs many the wrong way but its cold hard fact, Science proves a feeling not the other way around.

Back to our regular scheduled programming, you've made quite a few assumptions about the nature of bally's rant and gone straight for the guns. Now I wont even attempt to answer for the man because its really not my place, but I do find it funny that you went to all this trouble ranting and raving and STILL completely missed the point.

HD themselves has said 87 or above. The argument was that you don't need 91, So what's YOUR point? That you have a problem with how the other point was made, or is this simply your opinion of an opinion?

So now you’re admitting your own doubtfulness on this subject with this quote and you what all of us to… lie? Did you know there are some younger forum members that could be reading this and now you just told them to lie and cheat their way into life! I’m I understanding this correctly?
There are 2 Rules in this life, 1: Never reveal everything you know, 2:.....

Take the weaker position and control from below.

Premium is a marketing ploy, hand over fist. Ever notice how Premium is branded as the cleaner friendlier petrolium? Kind of funny considering we're head first into the war on hydrocarbons. Ever notice how everything "Green" is extortionately expensive for the value provided? The narrative transfers to fuel as well, especially for those who "want" to be greener/environmentally friendly because of course its in all the magazines and all the cool kids are doing it, its unthinkinable to stand out from the crowd right? Around these parts the premium fuel is all branded as ~15% friendlier for the environment, "an environmentally responsible choice"

Higher octanes don't burn efficiently if the engine is not absolutely designed to absolutely NEED 91+, because the hydrocarbons don't burn off proper you actually get the ADVERSE effect of what its pitched to do. More waste out the tail and even dirtier valves...

"I’m a yogi eco person," she told Marketplace. "I don’t know if it’s true or not, but in my mind, I believe it’s true that if I buy the higher-grade gas, it burns cleaner."

She was shocked when she learned the results of the testing.

"I'm speechless," she said. "Now I’m driving my car knowing it has premium gas in it, wondering if my emissions are higher than if I was driving my car with regular gas."
You know what, if I was big oil I'd take advantage of these people everyday just the same. Big Oil isn't polluting our minds, but they're certainly maximizing the fact that logic seems to of been shot.

Now, how bout them bikes ;):D
 
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