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Discussion Starter #1
I don't do well with gray areas.

The spark plug gap according to the manual is .032 - .036.

In my mind that's a lot.
Is there a guideline for going narrower or wider?

The manual for fuel says 87 and 91.

My engine is running a little rough.
I bought the bike after it had sit in a garage for 3 years.

So I want to do new plugs and want to know which is the best fuel to run.
I'm currently using sea foam, which I think has made it worse!

Thanks in advance,
Scott
 

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I use 91 octane in my 2005 Vulcan 1500.

I set my front tire pressure to 39 PSI rear to 41 PSI it rises smoother and prevents tire cupping.

Here is a link with lots of tried and tested information on Vulcans.

https://gadgetsfixitpage.com


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Discussion Starter #3
I use 91 octane in my 2005 Vulcan 1500.

I set my front tire pressure to 39 PSI rear to 41 PSI it rises smoother and prevents tire cupping.

Here is a link with lots of tried and tested information on Vulcans.


Sent from my iPhone using Tapatalk
Thanks for the quick reply.

What does your manual say for fuel?
Mine is a 96.
 

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Drain the tank. Fill it with the highest octane unleaded fuel available in your area. Put in properly gapped plugs. .004 is not that much difference in the grand scheme of things.

Start and ride the bike. If it is still running rough. Leave the bike running. Go to the right side of the bike. Spray the area near the carb with carb cleaner. If the rpm rises you have an air leak that you need to find.


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Discussion Starter #6
My minimum RON is 91 with the formula ending up at 87.

I felt when I put in 93 it was exploding and not combusting.
 

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for fuel use only 87 regular, for plug gap use .034
 

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octane

the higher the octane the harder it is for fuel to ignite. That's why higher octane is used in higher compression engines to prevent pre ignition or spark knock. 0.032 - 0.036 is only four thousandths of an inch .Copy paper is 0.004 thick so its the difference between minimum and maximum gap on the spark plugs :nerd:
 

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This has been coverd a lot here on this forum, but basically, read what your manual says. I have a 2004 carbed 1500 Classic. Mine says 91 minimum RON/+MON /2, which just means Research Octane Number they use in Europe and Asia plus the Motor Octane Number and average them. In America, that number averages out to 87 octane, which is regular gas.

But not all Kaws are the same. Some manuals call for 93 RON+MON/2. That would be premium in America. Some manuals just say 91 RON. That is also premium in America.

For those who may not know ( I didn't whan I first started riding), octane is the point at which fuel detonates under compression, which causes heat. The higher the octane, the less quickly it will detonate under pressure, eliminating a catastrophic failure from a high compression pre-detonation. It isn't better fuel; it's the same fuel with added octane. However, it's worth noting some states require different additives, and some brands have additives for engines, so you may want to use it. If your bike runs fine on 87, but you feel more comfortable running premium, go ahead, it won't hurt anything but your wallet, and at 3 gallons a fill up it won't even do that very much.
 

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Discussion Starter #10
This has been coverd a lot here on this forum, but basically, read what your manual says. I have a 2004 carbed 1500 Classic. Mine says 91 minimum RON/+MON /2, which just means Research Octane Number they use in Europe and Asia plus the Motor Octane Number and average them. In America, that number averages out to 87 octane, which is regular gas.

But not all Kaws are the same. Some manuals call for 93 RON+MON/2. That would be premium in America. Some manuals just say 91 RON. That is also premium in America.

For those who may not know ( I didn't whan I first started riding), octane is the point at which fuel detonates under compression, which causes heat. The higher the octane, the less quickly it will detonate under pressure, eliminating a catastrophic failure from a high compression pre-detonation. It isn't better fuel; it's the same fuel with added octane. However, it's worth noting some states require different additives, and some brands have additives for engines, so you may want to use it. If your bike runs fine on 87, but you feel more comfortable running premium, go ahead, it won't hurt anything but your wallet, and at 3 gallons a fill up it won't even do that very much.

Thanks for the detailed answer.

BUT, the manual says "use a gasoline with an octane rating equal or higher than that shown in the table".

The table says Anti-knock(RON + MON)/2 of 87 and RON of 91.

So which one is it?
 

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Work the formula (87+91)/2

178/2= a minimum of 89.

However my book also states use a minimum of 90 combined. I use 91 at the minimum.


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Discussion Starter #12
The answer has finally pierced my dense skull.

I didn't understand that octane rating methods vary around the world.

It seems like US gas stations are rated using the AKI, and i just need 87 as was kindly mentioned in this thread.

Thank you all for your insight and patience.

Warmest regards,
Scott
 

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Short answer Both
 

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Sorry my bad , the page did not load up right away
 

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Best, most concise correct answer.

Many thanks
Concise correct answers are not always best in a forum like this. While the answer may be correct for the OP, it may not be correct for random people scanning through the thread. People don't always read everything. Sometimes explanations for an answer are more important for random readers than a concise answer. Just sayin' :)

My '01 1500 Classic FI has 9:1 compression and requires minimum 90 octane in the US per the manual. I had 87 in it at the first fill-up and it was doggy and got about 30 mpg. Once I discovered the 90 minimum, I switched to 93 and it has much better power and I'm getting about 40 mpg.

US uses the (ron + mon) / 2 so the person that said to that each model/year is different and to use only what your bike's manual says to use, in my opinion, is THE mostest correct answer!

Cheers.
 
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