Bonneville America Forums Forums Technical Forums General Tech Fuel Recommendations

What is the consensus here regarding the best grade and/or brand of fuel to use for our bikes? Any other fuel issues discussed would also be appreciated.

The best grade would be what is recommended by Triumph, which in the States is 89 Octane. Going to a higher grade is just a waste of your money. Refineries in the US only product two grades of gas Regular and Premium. The Plus grade (89 Octane) is achieved by blending the other two grades together.

Which brand of gas to use is like asking this forum which syn oil is the best. Generally, in the area you live all the gas is produced at one refinery. The only difference between the various brands of gas is if they add anything more to the gas (like extra additives or ethanol) at their tank farms before trucking it out to the gas stations.

Tom

I would like to pick your brain, Tom. At Shell, I can get a 93 Octane pump. Why is any grade higher than 89 a waste of money?

Chris

There was a very long discussion on this about a year or so ago. Some heated discussion from what I remember with a ton of facts being tossed around.All that aside....

I use 89 but have been forced into 87 a time or two. Ive also accidentally used 92....so...I stick with 89 as called out by my manual and have not really noticed a difference when running 87 or 92.

Higher octane (91 and up) gas burns more slowly and will actually give poorer performance when fed to engines that were designed to burn anything less than premium fuel. Running premium fuel in an engine that requires regular or mid grade will not give you more power or better mileage, but actually the opposite.

So why spend more for a fuel that will potentially make your engine run at less than it's best?

There is one thing, though, that could cause you to use a higher grade gas: age. As an engine gets older, carbon buildup on the tops of the pistons effectively increases the compression ratio, which in turn means you may find that the engine knocks when you use mid grade gas.

Living in Florida I have used Regular, and mid grade gas without a problem.

Tom

Even with the 904 BB, I still use 89 as before. Can't tell any advantage going to premium. I have used regular a few times when I had to. 89 works the best.

89 seems to be the consensus around here. Well, I don't think this is an earth shattering decision so I guess I'll switch to 89 and save a few bucks.
I had always heard higher octane provides more power.

Just rate of burn and I used to always run Premium too thinking it was better for my engine, it isn't. From what I have learned you just run the lowest octane you can without the engine pinging. The lowest one that doesn't ping should be giving you the best performance for your engine. Use high octane in high compression engines.

91 + octane is really for chambers with a compression ratio of 10:1 and up to around 11.5:1 (roughly) . What's the compression ratio of an average stock 785 motor ? I've always wondered .


You can put in this blank line right here : ____ :1

Octane rating is not a "grade" of gasoline.
It is not a rating of power.
It is not an indicator of quality.

It is a measurement of gasoline's resistance to ignition.

The higher the number, the greater the resistance.

That is all.

Terms like "regular", "mid-grade", and "premium" are marketing tools designed to fool you.
They want your money.

Well dang , Bill ! I see ya got that 9.2:1 in that little line I made ya ! Thanks , now I know they'll run on 89 with a CR South of 10 .

Yeah , it's funny that people think that 92 is "premium" , if they only knew that higher numbered gas is "retarded" , literally .

Who would have though Bill would have anything to say about octane?

I recommend using fuel. Just before you run out, I'd recommend getting some more....

I hauled truck load quantities of gas for many moons, but only in the northeast US region. Over the years I saw some of the majors (like Exxon New Haven) mothball their own loading racks & terminals in favor of throughput arrangements to other oil terminals. I do believe they save a great deal of money this way. The result is now many (but not all) brands of gas all coming from the same pipes, with an additive by brand of gas package injected into the loading pipes at the time of loading the gas into the truck for delivery to the gas station. The questions in my mind were: how good is the current fuel base stock in the terminal's storage tanks, and what are the additives? Neither piece of info gets too far past the people in house at the terminal.

Not all the gas suppliers do throughput. There is a website devoted to a handful of refiners who apparently go a notch or two further than the others in their desire to provide a quality additive package. Not coincidentally, the names I read also maintain their own loading racks / terminals. The link is in one of the old posts, but I don't recall where. I do recall that Shell is one of the members of the higher quality gas club, and I think Amoco? There are others as well.

Will one brand of gas vs. another make much of a difference in a 50-75 HP Triumph? I say in general, no, but others may swear the answer is yes. I would suppose the more exotic the engine, like a Ferrari or new Corvette or the like, the difference in gas would be more relevant than say, a '64 Belvedere.

I know I've had better mileage on 94 Octane over 91 by about 10-12 miles a gallon. Never tried 89-87. As for the brand... You have to gas at difference place in order to compare... Not so sure if the tests are always good ( I think the best word would be a feeling ), as you may get different response due to weather condition ( i.e : Wind ), or riding with other bikes and having to "follow" as opposed to your regular solo riding.

Thanks Bill, that's the best explanation I've ever heard on this one, and it even makes sense given higher compression means more heat like with diesel's for example.

Good one matie.

BTW, there are many in Aus who also believe Shell produce a finer refined fuel and now I'm pretty well convinced. Good post this one, thanks

Looks like I might (will) be saving myself a few pennies from now on too

After reading this, I was curious as to what the octane rating of standard unleaded petrol was over here, so I looked. Whilst I didn't find the right answer* (it's either 91 or 95, depending on who you ask), I did find something that was interesting and may clear up some misunderstanding in this (and other) threads:

There are a number of different octane ratings for petrol including RON (Research Octane Number) and RON (Road Octane Number). That's right, cats, there are 2 RONs used for measuring octane. The latter RON (Road) is 4-5 points less than the Research Octane Number so that 92 Research would be 87/88 Road. The quoted rating is also a minimum figure.

The question is: are you all using the same ratings?

*It did answer my question, after all!!

I guess you can't go by just compression ratio either. My 904 is 10.5:1 and I, like Pat above, haven't noticed any knocking or pinging with 89 (mid grade).

I've done the same comparison both town and highway riding many many time and generally haven't found any difference between fuels. Certainly nothing that would Pr1ck my ears up, or is that eyebrows

I would have to agree, that great of a gain in gas milage can't solely be based on octane but instead riding style and conditions. If 94 was that great we'd all be on it. I've racked well into the 180 mile range a number of times (before reserve), but the conditions were always quite similar: cool day (low/mid 60s) and constant slow speed (never really got above 65mph). And I always run premium whether it's 91, 92 or 93.

The dealer told me to put in the highest octane so I have been using 98! Sounds like that was a load of bollocks!
Any other Australian members here can tell me what they use?
It doesn't sound like the US folk even have 98 fuel.
ps -I'm averaging around 250km per tank,EFI bike.

I hate to complicate things even more, but I seemed to recall (about a year ago as Z mentioned), there was a suggestion of adding a capful of Marvel Mystery Oil in the gas tank. I think it had something to do with helping lubricate the piston seals, I don't remember.

Unfortunately due to my laydown & loss of bike , I can't report if there was any distinct advantage to it. I only did it for a few brief months. But the engine ran fine, never noticed anything unusual.

Think I was the one that posed that question. When I change the oil in my truck I also add a couple of bottles of Valvoline fuel injection cleaner; therefore was wondering if anyone recommended running a tank of carb cleaner at maintenance intervals.

Ssshhh , I hear that ole Snake Oil Thread slithering up .

Well it also helped with connecting rod seals and oil cooler bearings.

Actually, the US uses the following formula to describe the octane rating of gasoline (R+M)/2.
The "R" stands for RON, the son of an Exxon/Mobil executive. He had a bit of an incontinence problem, so for some strange scientific reason, the lab boys decided to strain the gasoline through his knickers. (the "k" factor - an industry secret...) They would then compute how many parts per million of gasoline (ppm) would pass through in a predetermined time frame and they called that "Octane", a corruption of the German "Achtzehn" which means "18", which was Ron's age at the time... Now as Ron wore boxers, this was a rather high number, and the scientists and engineers were very happy...

Meanwhile, British Petroleum got "wind" of this, and decided to do the same. One of the exec's had a son named Monte, and although his bowels were normal, he only changed his knickers once each month. So he was selected to provide his knickers (the "k" factor - an industry secret) for the BP labs to use. They named their results MONTAGUE in his honor, but since he wore briefs rather than boxers, they were soon dismayed to find the ppm numbers were much lower. They found that MONTAGUE wouldn't fit on the little sticker they put on their petrol pumps, so they shortened it to "MON".

The people of Britain were so chagrined when they found that the Americans had higher ratings for their gasoline that a great hue and cry arose throughout the land. So the British Parliament sent an emmisary to meet with the US Congress to try to resolve this crisis. Since no one wanted to offend anybody (the beginnings of political correctness) they decided that they would make the tiny pump stickers in America a little bigger and put a bogus formula (RON+MONTE)/2 on all the gasoline pumps.
Everyone was happy, and today only a few select people realize that "the price of crude" does not refer to raw oil, but to the final step in the refining process.....

octane rating

I am sold on using 87 octane in Canada. I was using 89 in the US west because it was less expensive (the whole ethanol rumble).

I would point out that there's some uncertainty to the way people usually measure mpg because of the judgement involved in filling the tank. I figured out a good way to get a solid reading though:
1) ride til you hit reserve and note the mileage.
2) add gas reasonably soon thereafter and note the amount of gas added.
3) next time you hit reserve note the mileage.

You now know that you've used exactly the amount of gas you added in 2) to travel exactly the difference between 1 & 3.

And you wonder why people can't come up with accurate mileage figures. Bill, what was I supposed to do with the mileage I noted in step 2?

How about setting the bike up straight (level) and filling to the top of the inside ring every time you fill up? Then the figures would be consistent.

Note: If you fill higher than the inside ring while level, you might hit the overflow when leaning on the kickstand.

Why not just fill it in while on the stand?

Obviously, you can. It's just harder for me to tell it's filled up as high as I want it while leaning over. And that's not accounting for unleveled ground at the pump.

I used to fill it standing up straight. A splash can result in gasoline on the nads, not fun.
Even if it doesn't get your nads, it gets on your pants and runs down under the seat and gets harder to clean up.

So I did a test, filled it on the stand and then stood it upright to top off; less than a tenth of a gallon difference. Not worth the potential crap.

I never fill mine too full, I have had gas leak out from under too many gas caps over the years. ( although I was filling Wendys bike on Conn. and not paying attention and pumped gas all over her bike. The auto shut off didn't work.)