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Gnarly Jokester
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1,796 Posts
Discussion Starter #1
Have been trying to find out the best fuel octane to use, but
there is no real consenses. Have heard from some that say
87 is OK, the Vulcan godess says to use 89, and the decal
on the bike says not less than 91..

Am wondering what the Haynes, Kawasaki Shop, and Clymer
Service Manual say about Octane rating?
 

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HAWK
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2,576 Posts
I have used 87 to 110 and have not noticed any difference in teh way the bike runs. Stay with the cheep stuff.
 

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Gnarly Jokester
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1,796 Posts
Discussion Starter #3
Still confused..

My dealer in Coeur D' Alene, Idaho said that the bike had only been
on the showroom floor for 2 days, but when I started driving it I
noticed that it ran rough at low speeds, so I drained out whatever
the dealer put in the tank and put in 92 Octane and it smoothed
out significantly.

I'm sure 87 octane would be great for Freeway speeds, but around
town I'm not so sure.
 

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and the Adventure Cycle
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6,141 Posts
I thought I saw in the owners manual that 87 is what's recommeded.

I usually run the higher grade, just cause they say it's supposed to be better. (But I still haven't figured out who They are ?!)
I have run 87 more than a few times, and can also say I couldn't notice much difference.

Run a few tank fulls of each, and see how you feel about it.

Here's one way to see if there's a difference ............

Try to pay attention while going up a particular hill you travel, with the bike in 5th gear, and keep it steady at whatever RPM's you feel comfortable with.(but not really flyin'... just a bit above "chuggin'" it) Then try the other grade the same way, same RPM's, driving conditions, (and preferably same temperature)
Try doing it when each tankfull is down to about ½.

I would think if one works better for your bike than the other, this way might tell.

Just a though, as I'm not a trained fuel systems analyst, and I have no written documentaion to back up this hypothesis.
Which means, if it comes down to it, I will deny everything !!

LOL​
 

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Ccspinner said:
I have used 87 to 110 and have not noticed any difference in teh way the bike runs. Stay with the cheep stuff.

yea stay with the sheap stuff...5 years ago it didn't matter what stuff you got but now it is like $3 a gallon...i use 87 octain...
 

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I started with the 92% octane to have the best gas, and sometimes it would run terrible. My son said that these bikes were actually intended to use 87% , but the 89% would be the equivalent of the 87% from 7-9 years ago. He was right! Better gas mileage and runs like a scalded dog. Just my humble 2 cents!
 

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Howdy folks just a little info for you on the octane thing . I use 93 in my 750 In reality all fuel (gas) it all burns at the same rate. The difference is the higher the octane the more anti knock compounds that are put in . Soif your bike or car is knocking you would a higher octane rated gas yes. And being that my bike has 10.3 to 1 compression . I will go with higher octane KRAWDAD7.
 

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i use 89 octane and get between 66 to 58 miles per gallon & the bike runs good. the previous owner used 93 octane and said he had no popping. i get the popping, but because the group said 87 is all you need, i compromised. but the next tankful , i am going to give 93 a try and see for myself.
 

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Howdy all Iuse 93 octane in my 750 the reason is that since the bike has a compression rating of 10.3 to 1 it is better to use a higher rated fuel. All fuel (gas) burns at the same rate the only difference is they put more anti knock compounds in the higher octane fuel. KRAWDAD7.
 

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Premium Member
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1,647 Posts
Owners manual states minimum of 87 octane. Mine runs fine on 87. With around a 30-50 cent per gallon price difference and climbing, if it runs good, use the cheaper fuel. The anti knock compounds cause the fuel to ignite slower which is why it won't knock as easily as a lower octane fuel. Running a higher octane fuel than necessary just wastes money no matter what the compression ratio. If it don't knock, run with it.
 

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Uber Member
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i find that 91 (mid grade) runs great. i get just a tad more mileage (an extra 3 mpg) and that way i shouldnt get gunk in my carbs either. my ownly worry now is everything in my area is 10% ethonol and that degrades rubber
 

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Krawdad7 said:
Howdy all Iuse 93 octane in my 750 the reason is that since the bike has a compression rating of 10.3 to 1 it is better to use a higher rated fuel. All fuel (gas) burns at the same rate the only difference is they put more anti knock compounds in the higher octane fuel. KRAWDAD7.
It's true that higher compression mandates higher octane, but there are several factors that will reduce the requirement also. Our engines are aluminum, which has better heat dissipation, so that's one point. Additionally, the head is DOHC 4 valve which has significantly better quench than any pushrod head, so that's another point. Hence why the bike runs pretty good on 87. I would still run 89 in it just to ensure that it's not knocking at all. Over time, the minor amount of detonation that's pretty much inaudible can cause damage to the engine. Better safe than rebuilding.
 

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If it doesnt ping with 87 octane, then use 87. High octane gas burns more slowly and leaves more buildup on the valves. At least thats what ive been told. Here in NY 87 octane is running around 3.25 to 3.35 a gallon, so Ill stick with 87.
 

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Once Banned
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I started using 87 octane a couple of weeks ago, and I can't tell the difference. Gas mileage is the same for me. 87 is a tad cheaper, too, costing a little over 2 bucks. I guess if I got it at someplace other than Shell or Phillips 66, it would run about $1.89. Man, I miss the late 90's when I could fill up for $3 or less.
 

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Rubline said:
If it doesnt ping with 87 octane, then use 87. High octane gas burns more slowly and leaves more buildup on the valves. At least thats what ive been told. Here in NY 87 octane is running around 3.25 to 3.35 a gallon, so Ill stick with 87.
High octane fuel doesn't burn any slower. It ignites at a higher temperature than lower octane fuel, hence why it's more resistant to detonation. You guys in NY are lucky! I remember when I used to live there, I could fill my Mustang up with Sunoco 104 octane!
 

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Once Banned
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Yeah, Rubline... Don't you remember in Thermodynamics? When pressure goes up (as in high-compression engines), heat increases. So you don't want your gas exploding like a diesel engine. Sheesh! Actually, I 'm surprised that my engine doesn't knock at 87. My compression on my EXP was as high, and I had to run 91+.

So, um, Shaker, what do they put in petrol to increase it's octane? Oil? Water? Hummingbird guts? Obviously it's not Seafoam - did you see the ingredients on that stuff?
 

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and the Adventure Cycle
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Shaker666 said:
You guys in NY are lucky! I remember when I used to live there, I could fill my Mustang up with Sunoco 104 octane!
We have Turbo Blue here in PA.
It's 109 proof. Can't pump it (legally) into a street vehicle though.


$1.89 Cegodsey ?! that's dirt cheap !!! Lowest around here is $2.77 for regular, and some places as much as $3.07 !!!

For my "Burnt Hand" ride I only ran 87.
For 321 miles, the bike ran great, no knocks of any kind.
I should've paid attention to the mileage I got, but when I'm ridin', there's other things on my mind.
I did fill up 3 times, but right now I'm not sure what's left in the tank.
I believe the furthest we went before filling was 151 miles, and I hadn't hit reserve yet.

I'm happy with the cheap stuff.
 

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Octane booster? Why, of course! Hummingbird guts! :motorcycl

Don't they just add some lead (or something related to its properties) to increase the octane rating? Some materials or chem-E needs to chime in here, I don't really know.
 
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