Octane??

[blo]

Ok, I've just got to ask:
In northern Europe it's almost impossible to get fuel with octane lower than 95, premium is 98. Are we taking about different octane scales?

[Hoomgar]

In my stock engines I can run anything but definitely choose the better quality fuel as saaz mentioned for many self-delusional knuckle-headed reasons. I get better fuel economy, the engine runs cooler and there is a noticeable performance boost as well. I don't experience any pinging or knocking with any grade. Cars have been an exception to that.

My GS1000 is not stock and is setup to use 90+ octane fuel. Anything lower
than that and I can get predetination issues as well as build up.
My preference for the higher grade is cleaner fuel and better
performance. Here in my area the jump from 89 to 94 octane
is 6 cents a gallon. I usually fill up 3 to 3.5 gallons at a time so
I am not going to sweat it over 18 to 21 cents more a tank.

To each his own. High octane for me.

Side note, I run 87 or 89 in my new car Just to be a rebel! :twisted:

[Hoomgar]

Ok, I've just got to ask:
In northern Europe it's almost impossible to get fuel with octane lower than 95, premium is 98. Are we taking about different octane scales?

I am thinking different scales?

[bwringer]

Good point about stock vs. modified -- you have to be willing to experiment and adapt, especially with older bikes. To some degree they have all been modified, if only by age, wear, and carbon buildup.

If your motorcycle runs better (cooler, faster, whatever) on premium, then run premium.

Even though it's made up of components from at least three different bikes, my GS850G is reasonably stock (stock airbox, exhaust, and jetting) so I'm going to try a few tanks of cheap stuff and see what happens. It runs perfectly now, so any decline in power or running quality should be easy to detect.

[bwringer]

About Euro vs. North American octane, a little Googling turned up this:

Octane ratings are misleading....
in Europe they go by RON (Research Octane Number)

Here, it's AKI (Anti-Knock Index...[RON+MON]/2)

RON: Octane based on no load
MON: (Motor Octane Number)....Octane Rating based on a loaded engine.

but....in general....RON= AKI+4 (approximately)


Who knows if it's true, but it makes sense.

[Anonymous]

My machine doesn't like low-octane fuel. It pings on 87, I can get by with the 89 octane 'plus' gas. I HAVE checked the timing, it was actually a little retarded so I left it that way. Maybe I have carbon buildup, dunno .. it has 21k miles, shouldnt be too bad. :shrug: ..

[saaz]

Euro and US octanes are different in tersm of how they are presented, so don't try and compare them. In a civilised country like Australia we also use RON. There are a few websites that explain the differences.

Here, standard ULP is 91 RON. Premium is 95 RON. Higher density fuels are 98RON. In Japan I believe that over 100RON is common, as a few of their second hand performance cars make it over here that need the high octane stuff.

[Anonymous]

Gas

I use the highest octane that Union 76 has, I also use it in my 5.0 mustang, and in my car is where I do my experimenting, because with a helmet on and loud pipes it covers up any minor pinging or detoation that my be occuring, so I have used my car as a test bed, I have noted that the BP, Chevron and Shell gas stations all take delivery for the same supplyer, but that union 76 has its own trucks for delivery, Union 76 also Claims, (but who knows for sure that its true) that they don't have MTBE's in there gas, I know this for sure, my comp. ratio is 9 to 1, with 76 gas I can run a Total of 32 degrees of total advance, but with the others 27 is about max, my bike at 3.5 gals means I have to pay about 65 cents, more a fill up so there is no big deal there, I do on occasion use the others if Iam stuck, but I have at least proven to my self witch I prefer, I also use it in my full race 650 BSA with cam, pipes , big carbs and a whooping 12.5 to 1 comp. ratio that is what it likes, I dont scrimp on money for my bikes I do that on the wifes car!!!!

[bwringer]

This is an old thread, but FWIW, I switched to 87 octane last week on my un-modified '83 GS850G. Well, OK, it's a frankenbike, but everything engine-performance-wise is generally stock, including carburation and timing, except for Dyna coils.

Four tanks so far, and no pinging or problems at all. Even deliberately lugging it in 90 degree weather caused no strange noises or running problems. Plus I'm about $2.00 richer, so I can get that extra cheese on my burrito.

Looks like Nick was right again!

With a modified bike, I would definitely run premium. But stock, they are designed to run fine on regular unleaded.

[Anonymous]

1981 cylinder head, 1983 block, and 1980 bottom end. It's a long story...

Well, bwringer, it's time to tell that story. Start a thread in the GS Stories section.

Nick

[saaz]

Yes, these are the stories we like to learn from.....

[bwringer]

Well, Nick, I guess maybe someone could learn from my sad story. In fact, you played the role of the last-minute calvary. Remember selling me that GS850 cylinder head a few years back? It's still going strong more than 15,000 miles later!

I'll sit down and post the story soon. It's got suspense, crime, intrigue, a few cliffhangers, and a shocking twist near the end just when you think everything is all OK. No sex, though.

[Anonymous]

No sex, though.

Pfft! Until you said that I was all set for a good read..

(Bite me, I'll use as many as I want!)

[Hoomgar]

OK here is an update on octane usage. Mind you I am used to my modified GS so putting gas in this stock little Kaw 550 I was thinking old school and was just putting the same stuff in it.

Well here is the break down of an experiment I started last week and have done enough now to post on.

I have been running the 94 in my 550 like I am used to running in my 1000 and it runs fine on it as expected. So I thought about the stock factor having not run a stock bike in almost 20 years and I put a tank full of 87 in it to see what it would run like. I run the tank down well into the reserve first to make sure it was a good octane switch then filled it up with Sunoco 87.

I ran that tank through it and by the end of the tank I noticed a real loud knock and oil spraying out all over the place. Now it will start but if you rev it above 4k oil sprays out and it sounds like a jackhammer.
I have been forced to junk it as a result.























No no no no no I am full of crap but had to snap a girdle or two before I gave you the real scoop :twisted: After I run that tank out I noticed two things right off the first tank full.

1. It seemed to pull better in the midrange than before, I always had to tack it up really high to get it moving. I swear it pulls better from 4.5 to 7k now than it did on higher octane gas.

2. This is back-wards to what a lot of you have said but I never had an issue with this one either way so it didn't matter but my top end was always a little rattly noising in this bike once it gets good and hot. Right around 4 to 6k it will rattle until you get the revs up. Sounds like a chain more than valves though? But with 87 in it it does this a lot less and I mean a lot! It almost stopped it. SO now I can save 12 cents per tank full! WooHoo No it isn't about money obviously as it is only 12 cents a tank difference for me but it's about using the right fuel for the engine.

So to sum this up I have run two more tank fulls through it of Sunoco 87 since the first (I am on the third tank right now) and I can say for sure it is actually running better than it did on higher octane. This in my past experience is the opposite of what happens in my 1000 on it's previous build. It runs better on higher grades for sure without a doubt. We'll see when I get it done this time. I am going to test it.

So I am slowly being converted over to a low octane man after a life time of doing the high grade because I now have a stock bike that definitely runs better on it and a new car that does not need high octane.

My wifes car is a rattle trap on low grade and requires the good stuff to mask the impending doom syndrome but my other engines are now running low grade gas.

I will be doing more and more testing on this as time goes. If you know my history on gas grades then you will appreciate this entry even more.

[TheBigRed]

Wow Mark, how long till Nick replies to that.

Anyway, as has been stated, bikes were designed for specific octanes and that is what you are finding out.

that 12 cents can add up though..

say I fill the cycle tank every 2 days of riding (just to and from work) that is .60 every two weeks.. Or a can (or two if you get the generic stuff) of soda you can treat yourself to every other week..



Amos

(or every 4 weeks, I could get myself some Snapple Elements Moon tea...)