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Discussion Starter #1
It looks like the 2009 Vulcan 900 Custom says it takes 87 octane gas.

Does anyone notice a difference or any benefit from 91-93?
 

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When I'd roll on the throttle it'd seem to spit and stutter some in the lower rpm range. Then it would back fire alot more for some reason. ( but my bike belches flames since it needs custom mapping ). Just seemed to do it more. I'd like to try 110 or 114 octane.... But I'm a little worried I'd melt something at that octane.
 

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I've never run anything but premium in my tank... no reason especially, but figured that the cost from 87 to 91-93 is minimal in this application, so why not give it the best? That being said, never have I had any pinging or stuttering from the good juice in the tank.

Just my opinion.
 

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Uh, you guys do realize that the Octane Rating just means that the gas doesn't combust until higher pressures, right? It has nothing to do with quality of gas, but everything to do with the compression ratio of your engine. Based on the cylinder size of our bikes, the fuel isn't exposed to enough heat for enough duration of time to necessitate anything beyond 87 octane. Running higher octane levels may actually be damaging to your engine because it burns the fuel faster and can cause heating issues. There is absolutely zero performance gain to be had from switching octanes, unless you mapped for it and were riding something a little more, shall I say, horsepower heavy.

EDIT: A smoother ride from higher octane is just a placebo effect of it costing more. Your gas mileage will be reduced and it will smell funny, but it will not make the bike run better. In higher altitudes you could even run the 900 on 85 octane.
 

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I agree Caj,,,,,,doesn't make any difference. The book says run 87,,,so I run 87
 

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I usually run 87. For winter storage though, I filled it with 91 only because having read a few posts from people in the fuel industry who said that there actually is some difference in the more "premium" grades in terms of refinement and extra cleaning additives... the higher octane rating really doesn't help us though since the 900 mill is not considered a particularly high-compression engine. The one time I tried a tank of 93 octane non-oxygenated it ran about the same but my gas mileage took a nosedive.

Over all, I think the best strategy is to go for the lowest recommended octane (87) to be sure you get the fullest combustion, and whenever possible stay with the so-called "top-tier" fuels and stay away from convenience store brands. The base gas may be the same, the difference is in the cleaning agents and other additives.

Disclaimer: I'm certainly no expert on this subject either, but this is just what I do and I'm always curious what others' experiences are. Take it FWIW...
 

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When I'd roll on the throttle it'd seem to spit and stutter some in the lower rpm range. Then it would back fire alot more for some reason. ( but my bike belches flames since it needs custom mapping ). Just seemed to do it more. I'd like to try 110 or 114 octane.... But I'm a little worried I'd melt something at that octane.
whatever you do, do not put that racing fuel in your bike, the pistons are not meant for that type of octane and will probably mess up your rings
 

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I'd like to hear more about this... What did you notice?
it tells you underneath the seat its self, what kind of octane to run. it should be 89 or higher. i aways run 93 in mine, one time came to a gas station and they only had 89 for the highest so had to put it in, didn't really notice a difference but i still put the higher of the three
 

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Discussion Starter #12
it tells you underneath the seat its self, what kind of octane to run. it should be 89 or higher. i aways run 93 in mine, one time came to a gas station and they only had 89 for the highest so had to put it in, didn't really notice a difference but i still put the higher of the three
That's odd.

The manual says 87.
 

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I can say that putting 93 in every 4th tank you can't go wrong just to clean the line but doing it every tank is a waste of money. Also remember to do your oil and coolant at leat once a year if you don't put the miles on.
 

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it tells you underneath the seat its self, what kind of octane to run. it should be 89 or higher. i aways run 93 in mine, one time came to a gas station and they only had 89 for the highest so had to put it in, didn't really notice a difference but i still put the higher of the three
Let me clear something up for you guys.

Under the seat (I just checked) the fuel subsection says: Fuel (RON) 91

Do not get this confused with the American octane rating system. The American system utilizes (RON+MON)/2 to achieve PON, which is the number you will see at pumps. Without delving into the math, the cheat-chart afforded on numerous octane rating sites says specifically:

Type of Fuel
"regular" gasoline in Canada and the US

RON
91–92

MON
82–83

PON
87

Therefore, the 91, achieved via RON, is the equivalent of 87 octane AMERICAN STANDARD fuel.
 

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Uh, you guys do realize that the Octane Rating just means that the gas doesn't combust until higher pressures, right? It has nothing to do with quality of gas, but everything to do with the compression ratio of your engine. Based on the cylinder size of our bikes, the fuel isn't exposed to enough heat for enough duration of time to necessitate anything beyond 87 octane. Running higher octane levels may actually be damaging to your engine because it burns the fuel faster and can cause heating issues. There is absolutely zero performance gain to be had from switching octanes, unless you mapped for it and were riding something a little more, shall I say, horsepower heavy.

EDIT: A smoother ride from higher octane is just a placebo effect of it costing more. Your gas mileage will be reduced and it will smell funny, but it will not make the bike run better. In higher altitudes you could even run the 900 on 85 octane.
I agree with most of what you said, but part in bold is incorrect, afaik. Should not cause engine damage, and higher octane fuels actually burn more slowly. That is why they are better able to resist the uncontrolled burn that causes detonation/knock.

Again though, I do agree that it could cause less fuel economy, etc.
 

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I can say that putting 93 in every 4th tank you can't go wrong just to clean the line but doing it every tank is a waste of money. Also remember to do your oil and coolant at leat once a year if you don't put the miles on.
Dunno about NY but here in MN most gas contains 10% ethanol. It keeps the fuel system plenty clean and free of moisture, etc.
 

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I agree with most of what you said, but part in bold is incorrect, afaik. Should not cause engine damage, and higher octane fuels actually burn more slowly. That is why they are better able to resist the uncontrolled burn that causes detonation/knock.

Again though, I do agree that it could cause less fuel economy, etc.
Hyundai and Ford have stated that running higher octane gas than what is supposed to be run in their vehicles can actually damage the catalytic converters from the increase in heat. Higher octane has a higher activation energy, and as we all know from biology, energy is lost in the form of heat.
 

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Interesting, never heard such a thing. So their vehicles that require high octane (if they make any) necessitate a special "high temp" cat?
 

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Discussion Starter #19
There is an amazing surplus of misinformation in this thread. I almost feel bad for starting it.


Engines are designed for a certain octane gas. Some need higher octane because they were designed to run on higher octane. I have heard a few people on this forum say that our bikes run better on higher octane gas so I wasn't sure if there was something I didn't know.


Thanks to those of you who have provided correct information in this thread based off of knowledge they have on the topic. To the others, it does us (and you) no good to spread internet hearsay.
 

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Underneath my seat the label states that I should a minimum of 91 RON, which equates to 87 Pump Octane Rating by the (R+M)/2 methods; (91+83)/2= 87. You should use the lowest octane grade at which the engine runs without knocking. If you are under a heavy load or something and it pings, then try a higher octane. Higher octane will increase power only if detonation is present. Unless you tune your bike to run on fuel higher than 87 it's pointless. It will not hurt your engine to run higher octane but it will not improve your performance. High octane does not outperform regular octane or clean your engine. Octane is fuel, not "engine cleaner".

Just my $0.02 though.
 
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