Why? The owner's manual calls for regular unleaded. That's reason enough for me. I, also, run pure gas when I can get it and get better fuel mileage with it. You can check here to see if pure gas without ethanol is available in your area.

http://pure-gas.org/

Another reason....................your motorcycle has a low compression engine.....9.5:1 if I remember correctly.

 

http://www.ftc.gov/bcp/edu/pubs/consumer/autos/aut12.shtm

As a rule, high octane gasoline does not outperform regular octane in preventing engine deposits from forming, in removing them, or in cleaning your car's engine. In fact, the U.S. Environmental Protection Agency requires that all octane grades of all brands of gasoline contain engine cleaning detergent additives to protect against the build-up of harmful levels of engine deposits during the expected life of your car.

 

Octane is a hydrocarbon. Like... methane, ethane, propane, hexane.... octane.

The octane rating (which is a terrible name because it's confusing) is the fuel's resistance to detonation. The higher the number the higher the resistance and the less likely the fuel is to ignite under pressure before the spark plug fires.

The VN900 has an average compression ratio and it doesn't run very hot (relatively, of course) so higher octane gas is, quite literally, a waste of money in this application.


———————
From my DROID.

 

Saw Dog, Higher Octane just means higher price. Buy the cheap stuff. As long as your bike isn't knocking, it'll run just fine on it.

 

Here is all you ever wanted to know about gasoline

Here's the short of it as it pertains to octane (taken from here):

Octane Facts

• Knock occurs when cylinder pressures are high. It is normal for an engine to ping a little at full throttle because cylinder pressures are very high at full throttle. Engine knock, however, should not be ignored since it can result in serious damage to the engine.

• High octane gasoline burns slower than low octane gasoline. The slow burn prevents engine knock when cylinder pressures are high.

• If your engine runs well and does not knock or ping on low octane gasoline, there is no advantage in switching to higher octane gasoline.

• If your engine knocks or pings, it does not necessarily mean something is wrong with the gasoline. It could be a problem with the engine’s electronic control systems, ignition timing or exhaust gas recirculation. On a high mileage engine, a carbon build-up in the cylinders can increase cylinder pressures and cause knock.

 

87 works great for me....never a problem.

 

I run 85 octane with no problem, but then again, I'm at 5200 ft. I switched from 91 to 88 and went from 52 mpg to 48 mpg last summer. When the bike came out of storage, I took a chance on running 85; 6 tanks later, still getting 48 mpg with no ping or knock.

 

The owners manual actually calls for a minimum of 90 octane. If you look on page 34 (at least for the vn900 b) it states" use clean,fresh unleaded gasoline with a minimum antiknock index of 90. The antiknock index is posted on service station pumps"

 

Antiknock index is different then octane rating used in America. We use the (RON+MON)/2 method. Which gives a minimum octane of 87.

 

well hell,guess I was just as confused on that as a virgin in a whorehouse

 

Don't use high octane as it will make the bike harder to start when cold. I found that out myself. I read why elsewhere - something to do with low compression engine and high octane requiring hotter flash point (or something like that). It doesn't seem to hurt once you are up and about but there is no advantage when running and having to crank the starter 3 or 4 times is annoying.

 

Its been said befor!! Vulcan owners buy the cheap stuff!! True dat!!

 

higher octane 93 fuel does not = more power, whoever told you that is mistaken, that's not why they make higher octane gas, and your owners manual is wrong if it tells you to put in high octane, only use 87 regular in your 900 or you risk damaging the engine

 

I think he would be referring to a non-USA manual where ratings are different hence the manual is not wrong. Regular in Aust is minimum RON 91, premium is 95 and ultra is 98. A lot of very knowledgable people recommend using premium fuel in their cars despite a higher price as it improves efficiency and burns cleaner. These benefits are not there in a VT engine like the Vulcan. I found that 98 octane causes hard starting for me whereas in my wife's V-star it works fine.

 

Well, there is nothing worse than a motor that is hard to start...Based on the feedback here, I will defiantly go back to the non ethanol cheap stuff.

Thanks for the comments everyone!

 

gas?

I bought my bike 2 1/2 years ago used with 9k on the engine. I now have 24k on her. I have used the high octane in her since i got her. Here in texas its hard to get REAL gas. Question is do I swap back to a lower grade of gas or keep using the higher grade . I never have had any probs with her starting usally on the first try she fires up . I average 47mpg riding two up.

thanks
Sketter

 

I bought my bike 2 1/2 years ago used with 9k on the engine. I now have 24k on her. I have used the high octane in her since i got her. Here in texas its hard to get REAL gas. Question is do I swap back to a lower grade of gas or keep using the higher grade . I never have had any probs with her starting usally on the first try she fires up . I average 47mpg riding two up.

thanks
Sketter

You can use whatever you want, but premium isn't necessary. It took me a while to figure out which grade to use since the manual is confusing to say the least, but I noticed no difference in performance whether I used 92, 89, or 87 octane when I first got it, and I've been using 87 ever since.

 

I use 87 octane in my 9er, and it runs just fine. I tried one tankful of 89 octane and noticed no difference. Went back to 87. Now on my Nomad, it liked premium gas and ran noticeably better with it. It ran on 87, but preferred the higher octane stuff. Different bike, though. No point in wasting money on the expensive stuff when there's no benefit to it.

 

Since this 900 custom is my first bike, I've been told "you can't put anything but 93 octane." Ive had my bike for about 2 years and been using 93... Would it make a difference if I were to start using 87 now?


Sent from my Motorcycle iPhone app

 

The engine won't know what you're using. 87 is fine.

 

The compression ratio for the 900 is 9.5:1
What would the compression ratio need to be to require 93 octane fuel?

 

Compression ratio is only one factor to decide if premium is needed or not.
Cam timing, cylinder head design, etc, etc, etc,...the list goes on and on.
The new Mazda's have 12:1 compression ratio and yet take regular fuel!
In the olden days, a rule of thumb was about 9:1 was the top cut off point for regular fuel.

 

You get 47mpg? I'd say that's very good, I get around 33mpg, I would love to get 47, I'd say that if you're using high octane and getting 47mpg and have no problems, don't mess with a good thing.

 

When I first got my bike I put in 87 "regular" and the bike ran rough, sputtered and actually stalled once. This was with less than 1000 miles on it. I now run almost any kind of mid grade 89-91 with good results. I notice no performance increase with the use of hi octane fuels. My last tank was 89 octane and I got 52.6 mpg's. Occasionally I'll put in regular thinking that perhaps I got a bad fill on that occasion but my performance always decreases when I use it. My advise to anyone who asks my opinion is to use the LOWEST OCTANE that produces the best results with your particular bike at the elevation you live in. Their are too many variables to list so do your research and track your mpg's.

 

Try using 87 regular octane, the bike might run a bit hotter with it but test it out and if it starts pinging, go back to 93 octane, if it runs fine then you can stay with 87 regular.

 

Ok so now that it's pretty obvious I can use 87, do I have to completely drain the tank before adding the next/different fuel grade to the tank?


Sent from my Motorcycle iPhone app

 

As others have said, in the 900, it's a waste. Higher octane prevents detonation so it enables more compression and more power. It is not the source of power, it's simply an enabler (like a heavy duty rear end in a hot-rod. The heavy duty rear end doesn't increase power, in fact, it's weight and friction decreases it, but it enables 1,000 horsepower+ engine output because it can withstand that type of force against it.)

Higher octane allows an engine to produce more power without damage. However, our 900 engines are not doing any of the things that we would need higher octane for (higher compression, forced induction, etc.)

Also, a quick comment: The manual recommends 91 RON, which some people get confused on. 91 RON is basically equivalent to 87 R+M/2, which is the standard of measurement we use here in the United States. So if you're in the US, use 87. Higher octane provides no benefit, you'd just be wasting money.

If you want your engine to stay clean, run a can of seafoam in it every once in a while. It'll clean your fuel system and eliminate deposits better than any fuel will.

I have a hard time believing people on VN900's who claim to be getting better performance aren't just tricking themselves into believing it, or there is some other variable (like different batches, different gas stations). I mean, I wasn't there, I don't know... but it doesn't fit with the science and it doesn't fit with my experiences anyway (Octane doesn't modify performance, in fact, because higher octane fuels are harder to burn, which is the precise reason they don't ping in high compression engines, they should actually reduce power).

I dunno, maybe those folks have better butt-dynamometers than I do , but it doesn't make any sense that higher octane would increase performance or cause a VN900 to run smoother. Maybe if it's been well modified, but definitely not stock.

 

I dunno, maybe those folks have better butt-dynamometers than I do , but it doesn't make any sense that higher octane would increase performance or cause a VN900 to run smoother. Maybe if it's been well modified, but definitely not stock.

elevation, temperature, how much air is hitting your fuel all effect this. We can all give advice but you will have to feel it out for yourself and your situation

 

atineo, no draining needed. Just add the 87 to whatever you have in the tank. I did that with no issue from premium to midrange and midrange to regular.

 

Wait, if you add 87 octane gas to your tank with some 93 octane already in there, your gas tank will explode. It will go Boom