What about premium gas...

another plus to premium is no ethanol. At least at my nearest station it isn't. i also look for stations with separate pumps for premium.

bocaj wrote:

another plus to premium is no ethanol. At least at my nearest station it isn't. i also look for stations with separate pumps for premium.

You're lucky. Most all stations here have ethanol, even in the premium fuel. Only a couple places in town have ethanol free premium here.

Chevron here is one of the few that doesn't have ethanol in the premium. It seems to also be the only one with the highest octane rating of 94.

The Husky station I use, the highest octane rating they have is about 97-98. I dunno whether or not there's Ethanol in it though.

That's not even legal in BC. The highest they will allow is 94, even for marine gas. I'd like to know where you got those numbers from.

SheWolf wrote:

That's not even legal in BC. The highest they will allow is 94, even for marine gas. I'd like to know where you got those numbers from.

Off the pump itself. The lowest they have is 90 for Regular. I'll look again when I get around to tanking up. BTW, the Husky in question, is behind Stupid Store up the hill in Kamloops.

I'd say 87 - 89 yeah...that's way too high. Husky's highest octane is 92, regardless of where you tank up. The next highest is Shell Gold, which is 93.

That 97-98 Octane is likely RON (Research Octane number). What is typically on US pumps is (R+M)/2, that is, the average of the Research(RON) and Motor (MON) Octanes. RON typically is significantly higher than MON, so that's why the average usually is about 87 for regular, and 92-93 for Premium. However, as you go up in elevation the needed octane goes down, so in mountanous areas you typically see lower octanes than at sea level.

There not much hope for non ethanol gasolines in the future. The Renewable Fuels Standard requires such a large amount of ethanol to be in gasoline in the coming years that even if every drop of gasoline in the US had 10% ethanol, it wouldn't be enough. That's why automakers and the EPA are being pressed to approve 11-12% ethanol blends. But that won't be anywhere near enough either.

Husky and Mohawk both use ethanol in their gas. So far Chevron and Shell are still free of it.

ZED wrote:

It is interesting, but let's all please try to leave it over there.

Cool thread! Even funnier than all the threads about the "best oils". Reminds me of the saying " Opinions are like armpits - everyone has a couple, and they ususlly stink" Seems like we live in an opinion-based society, IMHO.

Yes. And what astounds me is that people keep starting oil threads!

Try a search on the web. You'll find a lot of very well documented professional data. But, I guess some folks just want to push their opinions and others would rather believe some guy on a street corner instead.

Now, what the heck were we talking about here again???

mwakey wrote:

The boys over at SMJ are going round and round about this very fact. Interesting thread.

http://www.supermotojunkie.com/showthread.php?t=77106

I was interested, so I chased the rabbit. For those too lazy to dig through the threads--once you sift through the amateur hour someone actually came up with an article from the Wall Street Journal that cited actual sources (American Petroleum Institute) and the answer is that on average a fuel pump hose holds 1/3 of a gallon of fuel from a previous user. Whatever octane they used (on a single hose pump) starts your fill-up.

malibu_dan wrote:

mwakey wrote:

The boys over at SMJ are going round and round about this very fact. Interesting thread.

http://www.supermotojunkie.com/showthread.php?t=77106

I was interested, so I chased the rabbit. For those too lazy to dig through the threads--once you sift through the amateur hour someone actually came up with an article from the Wall Street Journal that cited actual sources (American Petroleum Institute) and the answer is that on average a fuel pump hose holds 1/3 of a gallon of fuel from a previous user. Whatever octane they used (on a single hose pump) starts your fill-up.

Some simple math based on the 1/3 gallon proposition:

If last customer pumped 87 octane and premium is 93 octane, then:

Pumping 2/3 gallon of "premium" results in net 90 octane.

Pumping 1.0 gallon of "premium" results in net 91 cctane. (WRR recommended minimum)

I usually fill my tank with 1.2 to 1.6 gallons, giving me well over the minimum 91 octane. It does not, however, keep me from being pissed at paying for all premium and not getting it - especially at $4 a gallon!

Um, I hate to buck the trend here, but at 2500+ miles of nothing but 87 and no problems at all. I don't pound the motor to oblivion much if at all, but I don't see the need. I understand the no knock sensor and all, but I've got no knock and the thing runs perfect.

I also don't run high test in the GS and for 28k miles no problems there. I also stopped putting high test in my track bike- unless at the track- and it has 19k on it. I've never regularly run it in my race cars or any other car for that matter.

longtallsally wrote:

I understand the no knock sensor and all, but I've got no knock and the thing runs perfect.

How do you know that you don't have any knock? (since you can't always readily hear it). Not saying you'll have problems with it right away, and maybe it will never do enough damage to not run, but it would be interesting to see the inside of your bike's head and top of the piston in 20k miles to see if your assumptions hold true. That would be great, if so. Still, for the extra 30 cents every fill-up, I'll stick with premium. But then, I often do oil changes more often than the recommended intervals, too.

longtallsally wrote:

I also don't run high test in the GS and for 28k miles no problems there.

But don't GS have knock sensors and compensate for less than ideal gasoline octane (similar to all modern autos)? Not sure about your track bike since you don't mention the make/model.

BluePill wrote:

It does not, however, keep me from being pissed at paying for all premium and not getting it - especially at $4 a gallon!

I'd be more upset by not getting what I paid for when gas is $2 rather than $4. We actually get a better deal on premium when gas prices are high. When it was $1.99, the spread is about 20 cents. When gas is $4.50, the spread was about 20 cents. The higher gas prices go, the more economical it is to buy premium and to drive a vehicle that uses high octane (and gets the proportional better performance and better gas mileage). Obviously no advantage to run high octane in a vehicle that isn't built to take advantage of it.

Chadx wrote:

How do you know that you don't have any knock? (since you can't always readily hear it). Not saying you'll have problems with it right away, and maybe it will never do enough damage to not run, but it would be interesting to see the inside of your bike's head and top of the piston in 20k miles to see if your assumptions hold true. That would be great, if so. Still, for the extra 30 cents every fill-up, I'll stick with premium. But then, I often do oil changes more often than the recommended intervals, too.

But don't GS have knock sensors and compensate for less than ideal gasoline octane (similar to all modern autos)? Not sure about your track bike since you don't mention the make/model.

I guess I don't. But I also have never in a few hundred thousand miles of riding/driving had a problem with a fuel system or and engine. I can't be that lucky. I also can't give a reason why scientifically either.

You are correct on the GS- it has a fuel map to allow darn near anything combustible.

The track bike is a CBR954. Over 10k of commuting on it with tractor gas and no worries. Me no know, just thought I'd present a different perspective.

Now when it comes to oil changes, I'm a bit of a loon and do those WAY often. 3 so far on the WR and going to do another probably this weekend.

Hhhmm...interesting conversation. Been away awhile, got bored at work...so sneaked a peaky, and found a boiling pot of opinions. Its all good! But, kind of like the "best oil" debate. I rarely weigh in on these discussions, but just can't resist this one. My background gives me some unique qualifications in this department. I've been a plant engineer multiple refineries making gasoline & motor oil for several years. Don't do it anymore....doubt much has changed....but beats me. Anyway, here's my 2 cents on gasoline (from a practical standpoint):

Basically, Octane is an arbitrary (mathematical) number indicative of "anti-knock" characteristics. The higher compression an engine, the higher the Octane # required to prevent detonation....which is a "post" ignition situation, not a "pre" ignition situation. Detonation is like a delay in ignition of some small pockets of fuel vapor after the main flame front has propagated thru the combustion chamber. In other words, some of it didn't get all burned with the inital spark ignition. So, you here a tapping or gurgling noise...especially as you accelerate. While its not good for your engine over an extended period of time, it really shouldn't cause any serious damage in the short run. Primarily because the amounts of fuel/vapor post igniting are fairly small. So, don't panic if you're motor is detonating on low octane. Just enjoy the ride and switch to a higher octane gasoline at your next opportunity.

Pre-ignition is a whole different monster. It can be terribly damaging to a motor. It is usually caused by a hot-spot within the combustion chamber. For example, let's say there is some carbon buildup on top of the piston. After running for some time, this spot gets red hot....like a branding iron. Then, on the next intake cycle, as fuel/vapor enters the combustion chamber and begins compressing.....the fuel mixture is prematurely ignited by the hot-spot PRIOR to the spark from the plug. Thus, the term Pre-ignition. What makes this so different from detonation, is that there is an entire combustion chamber of fuel mixture (not just some unburned pockets). It can create a tremendous force (from explosion) at the WRONG time. Results are usually catastrophic from pre-igntion....i.e. it can blow a hole right thru the top of your piston.

Pre-ignition would not normally have anything to do with Octane rating. While Detonation is a problem totally associated with Octane rating....in that higher Octane numbers help eliminate Detonation problems by helping the flame front ignite and burn ALL fuel vapor in the combustion chamber all at once. I hear these terms inter-changed with each other often, and used incorrectly. Now, let's get back to the WRR/X issue.

If she's Detonating, you're gonna hear it and notice it (at least if its bad enough to hurt your motor over an extended period). Change your gasoline to a higher octane. If you can't get it in your area, consider stocking up on Octane Booster (Enhancer). That's an acceptable fix most of the time. If she's not Detonating, run it all day....regardless of the Octane #.

If it will burn, it will run! Gasoline, Naptha, Mineral Spirits, Denatured Alcohol, cigarette lighter fluid. Remember that if you're ever in a pinch with an emergency. You might not like how it runs, but you can probably sneak by. Obviously, don't run a fuel oil (Diesel, Jet A, Kerosine, etc). No...that won't work, even in a pinch.

Now, back to gasoline. Here's a real surprise for a lot of people...so brace yourself. Higher Octane gasoline will not make your bike run quicker or faster (i.e. better performance). Its only going to solve a Detonation problem (which is very important). I meet a lot of riders that think their bike will "go faster" on higher octane gas. Just not true. Sometimes we switch to a higher octane (like 110 race gas) in our 2-strokes to actually "smooth out" performance off the bottom end....because most "race gas" actually burns "slower" than standard automotive gasoline. So blending with that can help take an abrupt edge of a carb'd bike, high compression motor (sometimes). Its NOT like running Nitro, no not at all.

Personally, I run Premium whenever I can because R² calls for it. But I've had many situations where none was available and I've filled her up with 87 Octane gasoline, and she ran just fine (i.e. No Detonation).

That's the bottom line. That's my story and I'm sticking to it. Hope you find it helpful information.

HF

Thanks HF!

I certainly prefer 91+ octane fuel as per Yamaha's recommendation, however, due to the remoteness of the areas that I go to play and the limited fuel capacity of R², I frequently have to run 87. I have never experienced detonation.

I guess I'm not so dumb after all.

The last 2 paragraphs are what helped me the most as it reaffirmed what I've read before...

Nope...you're not a dope! You can run her forever on that lower Octane if she's not Detonating. Just pay attention to it as the weather changes from hot & humid to cold & dry. The gasoline formulations change from summer to winter, and between geographic regions (based upon altitude). The higher the altitude, the less Octane you need. That's why you only see 85 or 86 Octane for Regular in Colorado, for example. Don't automatically think that is bad...as in worse than 87 or 89 in Houston. In reality, you'd be more likely to Detonate on Regular in Houston (near sea level), than you would on Regular in Denver (with a much lower Octane #). The air density has a lot of affect on the outcome....since the fuel mixture is an "AFR"......meaning "Air/Fuel Ratio". Fuel is only part of the equation.

HF

Highfive wrote:

Nope...you're not a dope! You can run her forever on that lower Octane if she's not Detonating. Just pay attention to it as the weather changes from hot & humid to cold & dry. The gasoline formulations change from summer to winter, and between geographic regions (based upon altitude). The higher the altitude, the less Octane you need. That's why you only see 85 or 86 Octane for Regular in Colorado, for example. Don't automatically think that is bad...as in worse than 87 or 89 in Houston. In reality, you'd be more likely to Detonate on Regular in Houston (near sea level), than you would on Regular in Denver (with a much lower Octane #). The air density has a lot of affect on the outcome....since the fuel mixture is an "AFR"......meaning "Air/Fuel Ratio". Fuel is only part of the equation.

HF

Yep, went to grad school in CO. Glad you could explain what I've known...

Thanks Highfive. That was a very informative and useful description of detonation vs. preignition.

Great explanation, HF. Now I won't be as worried when I have to pump regular into the R². Doesn't happen too often, but occasionally. Should happen even less once I'm done with my planned rotopax solution. Otherwise I'll keep running premium on a day-to-day basis. It's worth the 30 cents/tank to keep me from imagining every little noise the engine makes might be light detonation.

Highfive wrote:

Now, back to gasoline. Here's a real surprise for a lot of people...so brace yourself. Higher Octane gasoline will not make your bike run quicker or faster (i.e. better performance). Its only going to solve a Detonation problem (which is very important). I meet a lot of riders that think their bike will "go faster" on higher octane gas. Just not true. Sometimes we switch to a higher octane (like 110 race gas) in our 2-strokes to actually "smooth out" performance off the bottom end....because most "race gas" actually burns "slower" than standard automotive gasoline. So blending with that can help take an abrupt edge of a carb'd bike, high compression motor (sometimes). Its NOT like running Nitro, no not at all.

Personally, I run Premium whenever I can because R² calls for it. But I've had many situations where none was available and I've filled her up with 87 Octane gasoline, and she ran just fine (i.e. No Detonation).

That's the bottom line. That's my story and I'm sticking to it. Hope you find it helpful information.

HF

HF is on the right track... Having built racing engines for years I have seen the damage caused by PRE-IGNITION and DETONATION. Pre-ignition manifests it's self as blown rods and cranks, piston "crowning" and a horrific exhaust noise. Detonation burns valves and pistons. I have always used a RAD (ralitive air dentsity meter) at track side and ajusted octain to minumize detination. Then I used blends of hydrogenated fuels to prevent pre-ignition to achieve the most HP for the day. In 6 hour racing one fule would be used. For 12 and 24 hours races the fuel would change as the condition changed.

BTW, these motors are 13.5 to 14.4 to 1 compresion and topped out at 14,700 RPM and 1000 to 1300 cc RR bike motors.

A mass biult WR250R could run all day and just about any fuel over 85 octain. Yamaha wants to be safe, spec the high octain...any condition... -30F to 120F...91 is safe and will prevent some guy from chugging on 85 in Death Valley in 125F and detonating his motor...then a warrenty service... IMHO...