Changing octane...

[B12Teuton]

I wonder how the B12 engine would run on Martinis?
Vodka or Gin?

I'm a Bombay Sapphire man.

[Desolation Angel]

I wonder how the B12 engine would run on Martinis?
Vodka or Gin?

I'm a Bombay Sapphire man.

Finlandia for me, please.

[rocketman1]

In NZ we have 96 and 91 Octane unleaded my bike goes just fine on the 91 Octane, full choke of the first 3 or 4 seconds then ease off for about 10 seconds and Im away no probs. daytime temp about 18 Degrees Centigrade

[B6mick]

Ok, I do just luv, the mighty fuel debate.  
The nuckle heads tinkering with ya carbs, find that hard to believe, but could happen. But being a wrench myself, I ask this. If its running fine why would anyone pull the carbs to tinker. Drain the bowls yes, but unless the owner asks for the carbs to be tinkered with, no way basic tune up never, if the bike ran real bad, when it came in, yes but otherwise, no way the workshop would go broke in a week.
My suggestion is, start using premium grade fuel again, after 2 to 3 tanks you will have the answer. Your bike likes premium, or someone been stuffing with your carbs and did a shocking job.
Yes the other thing is to watch out for winter grade fuels, can some times play havoc, I dont know about over there, but here they are sneeking into the fuel, ethanol again, Aussies, be carefull BP seems to be the main offender. Well its not actually BP its some of the operators. Bp's premium plants is off line again, for reasons unknown. Most Bp stations have signs up on all premium pumps, out of order. But some seem to have premium, but I am assured it is not BP. Have had a few bikes in over the last few weeks running off song, the 1 st few had us at the shop stumped.
Common denominator, BP premium fuel, drain tank and carbs, fresh fuel from another supplier.  yep no problem, on song and running fine. Just to prove the point we now have 5 batches of fuel being tested by the CSIRO.

[aussiebandit]

Ok so that's Shell Optimax, BP, that Woolworths crap that I won't put in the B12 or the M750 (unless there's no real choice).

That leaves Mobil, Caltex and not a lot else.

[PaulVS]

Keep in mind the U.S. octane rating method is different from Europe, Australia, and New Zealand.  If I'm not mistaken, 91 octane there is the equivalent of around 89 octane U.S.

(Someone feel free to correct me if I'm wrong.)

[ergopower]

The higher the octane rating, the higher temperature/pressure is required for combustion. That's good in a high-compression engine, it prevents the mixture from detonating instead of burning. But in a lower-compression engine, it can mean incomplete combustion because the flame front is slower at lower temperature/pressure, potentially too slow. In that case, unburnt residue gradually builds up in the cylinder, and this creates hot spots. It's generally not noticeable if you continue to use high octane gas; but if you then switch to a lower octane rating, the hot spots can cause detonation/knocking/pinging/whatever you want to call it. So using higher than necessary octane for long enough can mean you are stuck using it. Have you tried going back to high-test yet?

Brian

[pmackie]

Some additional comments, just to add to the complexity...

Gasoline is NOT a static product. Due to many factors, including gov't legislation and regional historical conditions, gasoline formulations need to change seasonally, sometimes more often.

One of the common things that changes is it's vapour pressure, often measured using the Reed Vapour Pressure method (RVP). The basics are that the light ends of the fuel (those parts that vapourize easily at ambient temp) are reduced in the summer and increased in the winter, usually in several steps. You need more light ends in the winter to allow the fuel to vapourize easily at lower ambient temperatures to allow easier starting. If you don't have enough percentage of the fuel that will readily vapourize, you cannot easily start the engine.

In the summer these light ends are reduced for a couple of reasons.
1. Too many light ends vapourizing can lead to vapour lock in some fuel lines/fuel pumps etc.
2. Excess light ends entering the atmosphere lead to an increase in ground level ozone, or smog.

Anyway, a common isssue every fall is that as the temperature drops, the current "summer" RVP gas in the system may lead to harder starting, especially in carburated engines. As the higher RVP gasoline makes its way through the whole system, the effect goes away.

In the case of October/November deliveries in Texas, there are many refineries still down and/or just coming back on line. It is likely there is still lower RVP gasoline coming out of the refineries in your area.

I expect the effect you are seeing has more to do with the supply/invertory logistics in your area and less to do with octane.

[jared1970]

Due to lack of gas, there has been rumors of poor quality imported gasoline.  Not sure if this has something to do with it.

I always ran 89.

I think there's merit to this rumor. Immediately following Katrina, I noticed my car would ping no matter what octane I ran in it. I normally run 89 octane in all my vehicles, as its state subsidized here in Iowa, making it about $.10/ gallon cheaper than 87, and much cheaper than premium.
However, in recent weeks I've noticed this problem has subsided, and I think the poor quality gas problem is starting to phaze out.
You may also want to try buying the same octane gas from several manufacturers. One manufacturers 87 octane is not the same as another's 87. But most importantly, check your owners manual to see what octane fuel Suzuki recommends you use in your Bandit.

[Wooddog]

My Mother has managed convenience stores for 20 years and she tells me just because you pay for the 91 octane, does not mean you are getting 91 octane.  She says when the fuel truck fills up the 87 octane tank and needs to empty the rest of the truck,  he puts the 87 octane in the 91 tank, and that seems to happen all the time. So who knows what octane you are getting. I would say buy the cheap gas and if your bike does not run well on it then go to wal mart or auto zone and buy a bottle of octane booster and add it to your gas.

[Kickstart]

Keep in mind the U.S. octane rating method is different from Europe, Australia, and New Zealand.  If I'm not mistaken, 91 octane there is the equivalent of around 89 octane U.S.

(Someone feel free to correct me if I'm wrong.)

Europe (and Aus I think) uses the Research Octane Number (RON). The other common measured octane rating is the Pump Octane Number (PON) which as a rule of thumb gives a rating about 10 points lower for the same fuel. The USA uses the Motor Octane Number (MON) figure which is the average of the RON and PON, so as a rule of thumb about 5 points lower than the European figure. Standard unleaded fuel in Europe is 95 RON (nothing lower is available in the UK that I know of) while higher octane 97 / 98 RON is also available.

All the best

Keith

[Slider]

...from 93 (might actually be 94 ??) to 87 has caused some minor odd side-effects.  Has this happened to you?  I have an '01 1200.  For a year I ran premium in it.  Just seemed like the right thing to do.  We had a big octane discussion here recently and I decided I only needed regular grade gas.  My last tuneup was done while I was running premium.  So...

Now I think I'm hearing valve chatter as I ride and the bike is acting funky prior to warming up.  Choke doesn't seem to do much any more.  On premium I would close the choke fully, start the bike, which would idle fast, then I could open the choke to about halfway and it would idle normal as it warmed up.  Now not much happens with choke in any position and the bike dies easily until it's warm.  Seems to chug a bit at first and makes more noise than I remember (mechanical-rattley engine noises).

Should it have been tuned while running regular or is it telling me it doesn't like 87 octane?  Same gas station always, by the way.

Off the Bandit for a second, similar side-effects are occuring with my '82 GS450TX.  Hard to start, doesn't idle right, makes funky engine noises.

The choke quote above makes no sense to me. "Not much happens in any position", sounds stange. I wonder if it is a stuck choke cable.

 Mine hung up partly open on me -never to move much again, I might add. The mechanic thought the teflon? lining had wadded up and jamed.
A new choke cable worked. The other noises are ???

Up here in Beaver Land the regular gas works like a charm in my B1200. All crabbiness that the bike had prevously, turned out to be the disgustingly lean jetting legislated by the Gov't. Low speed jet reset and carb needles up a notch solved this with no detectable loss in mpg.
 

[Red01]

Europe (and Aus I think) uses the Research Octane Number (RON). The other common measured octane rating is the Pump Octane Number (PON) which as a rule of thumb gives a rating about 10 points lower for the same fuel. The USA uses the Motor Octane Number (MON) figure which is the average of the RON and PON, so as a rule of thumb about 5 points lower than the European figure. Standard unleaded fuel in Europe is 95 RON (nothing lower is available in the UK that I know of) while higher octane 97 / 98 RON is also available.

You're close Kieth. RON is what's used in many countries, but what you've got MON & PON crossed.

From Wikipedia:

The most common type of octane rating worldwide is the Research Octane Number (RON). RON is determined by running the fuel through a specific test engine with a variable compression ratio under controlled conditions, and comparing these results with those for mixtures of isooctane and n-heptane.

There is another type of octane rating, called Motor Octane Number (MON), which is a better measure of how the fuel behaves when under load. MON testing uses a similar test engine to that used in RON testing, but with a preheated fuel mixture, a higher engine speed, and variable ignition timing to further stress the fuel's knock resistance. Depending on the composition of the fuel, the MON of a modern gasoline will be about 8 to 10 points lower than the RON. Normally fuel specifications require both a minimum RON and a minimum MON.

In most countries (including all of Europe and Australia) the "headline" octane that would be shown on the pump is the RON, but in the United States and some other countries the headline number is the average of the RON and the MON, sometimes called the Anti-Knock Index (AKI), Road Octane Number (RdON), Pump Octane Number (PON), or (R+M)/2. Because of the 10 point difference noted above, this means that the octane in the United States will be about 4 to 5 points lower than the same fuel elsewhere: 87 octane fuel, the "normal" gasoline in the US and Canada, would be 91 in Europe.

It is possible for a fuel to have a RON greater than 100, because isooctane is not the most knock-resistant substance available. Racing fuels, straight ethanol, Avgas and liquified petroleum gas (LPG) typically have octane ratings of 110 or significantly higher.

[mike]

"An engine is like a woman"...
Take her to 5 star restaurants for years,
then try dinner at Bennigan's or Friday's, she's gonna bitch !!    

[Swamp Rat]

One other little tidbit. Most of the refineries dump there fuel to a common pipe line. They denote how much fuel they added to the system. When the tanker trucks fill from the loading stations they denote how much they took away and of what grade. Checks and balances.
  Many different refineries fill into this same system. The difference ends up only being the additives package. Kind of how you put a bottle of octane booster or injector clraner in your car is how the additives are added to the common gasoline. If you were to drive to one of these filling ports you would see several manufacturers additive tanks and only a few gasoline tanks. So when someone says it's all the same stuff, other than octane and additives, it truly is.