GS700 and gas type

[cyberdork]

My manual is alittle confusing with what type of fuel I should be using. It says 85 octane using one method and 89 using another method. We've had so many lawnmowers returned at work and the guy that fixes them says that the new ethanol gas is beating them up with 87 octane. Should I worry about running 87 in my bike or should I run around 91-93. Only gas available here is 87,91,93

[Grandpa]

This issue comes up all the time (which is fine, as it gives some of us a chance to put minds at ease).

I've been running 87 octane unleaded fuel in my GS bikes since 1986. I've never filled a tank with anything else.

Four consecutive 850's, and a GS1100GK for the last 9 years. The GK has 130,000 miles (there I go again, Nessism), most of them mine. All on 87 octane fuel exclusively.

If your GS700 is stock, you should run 87 unleaded fuel, go riding, enjoy the bike, worry less, and enjoy the motorcycle more.

Save your money. The price of 87 is high enough; don't pay for the fancy stuff , because you don't need it.

[cyberdork]

That's what I figured, thanks.

It's been so wierd, we've had 15 push mowers returned this year followed by a few weed wackers. About 13 of those mowers had their motors siezed.

[bwringer]

Mega-dittos to what Grandpa said.

I whip my GS850 like a rented mule on 87 octane, whatever's the cheapest around. I don't think you can even get gas in Indiana that's not 10% ethanol. It's strictly not an issue in a stock GS, unless your engine has been modified. In that case, you know who you are.



The lawn mower guy is all wet, too. Lawn mowers will happily burn just about any hydrocarbon -- if you look in the Briggs & Stratton manual, all you need is 85 octane, and alcohol in the gas is perfectly OK in any mower newer than about 30 years.

What kills lawn mowers is old, dirty gas that gums up the jet(s) -- same thing that happens to motorcycles that also sit all winter.

Fortunately, lawn mower carbs are very simple. I've been given several free "junk" mowers that fired right up after a quick carb bowl cleaning and half a tank of fresh gas mixed with the old stuff. They're not at all picky -- if I have old expired gas I want to get rid of, I mix it half and half with fresh gas and use it up in the mower.

[bwringer]

That's what I figured, thanks.

It's been so wierd, we've had 15 push mowers returned this year followed by a few weed wackers. About 13 of those mowers had their motors siezed.

People also like to buy new mowers/weedwackers and then fail to add the oil to the crankcase (or gas).

The motor seizes after a bit, then they quickly dump in the oil after the fact and take it back to the store.

Fresh, clear oil in a seized engine? Hmmmmmmmmmm...

[Clone]

Brian, which bike are you taking to NY if you are going to the rally?

[ohgoodtimes]

in colorado we have 85 87 and 91, i have run a couple tanks of each through the engine and i have to say the 87 works just fine, so i dont know if that is a vote for 87 or midgrade but that is what gives me the best performance. No hessitation or any problems.

[Mark whiz]

I've got 103,000 miles and 22years on my '85 700ES all using the cheapest 87 octane I could find. Pour in some Seafoam or even STP fuel injector cleaner 3 or 4 times a year and it'll keep going strong.

[etepesq]

I see lots of folks running cheap gas and say it's fine. I'm in Seattle, not sure if that matters, but I run cheap 87 octane in my car, so when I got my bike I did the same.
My young buddy racer head saw me reaching for the cheap button and slapped my hand.
I thought he was a bit much but I am here to tell you.... I feel a huge difference. I can even hear it.... especially if my GF is on the bike, try some high octane from Shell. They say cheap gas leaves tons of carbon deposits.

good luck.

[TheCafeKid]

Runnin high octane in your GS will leave TONS of carbon deposits. High octane gas is designed for high compression modern motors, which your GS is NOT. There are lots on here who will tell you the same. You are wasting your money, and dirtying your combustion chamber. Im not possitive, as I have NEVER run higher than 89 in my bikes, but I thought i recently read a thread where somone found info that lead to the idea that using high octanes can actually cause pre-ignition and piston holeing. I dunno for sure, but I DO know that using high octane in a stock motor is a waste of money.

[tommyboxes]

Glad someone asked this befor I had to. I ran 2 tanks of 91 through it and now I have some 89 in there. I figured that 91 was better for my old girl glad to hear that I should use the 87. My passat turob NEEDS 91 or I lose about 5mpg.

[Zook]

As all have said, 87 octane is fine. Even some of the newer bikes like the R1 call for 87 octane. They may have high compression but with FI and electronics they can make them run like scalded apes on regular.

The Shell ads are just that-ads. They want you to buy higher octane gas which gets them higher profits. Just like it says on shampoo bottles-"wash, rinse, repeat". The "repeat" is to get you to use twice the amount so you have to buy more. Notice the second time it lathers up a bunch more? That's because you got your head clean the first time.

The bike running better on higher octane is probably psychological. The gas co. tells you to run higher octane and you do, so you perceive it to run better. If it actually does run better then you have a problem with your bike that will get worse over time and you will need ever higher octane.

Shell says cheap gas leaves deposits...so, are they saying their 87 octane is "cheap gas"?

Always use what the factory says to use.

Oh yeah-there are two methods for determining octane. The "pump" method, which we use and the other, which everyone else uses, and their method uses a higher octane number. The gas is the same, but the numbers are different.
89 octane here is 91 octane across the pond. Not higher octane, just higher number.

[Steve]

Oh yeah-there are two methods for determining octane. The "pump" method, which we use and the other, which everyone else uses, and their method uses a higher octane number. The gas is the same, but the numbers are different.
89 octane here is 91 octane across the pond. Not higher octane, just higher number.

Yep, there are two methods: Research and Motor. To help explain this, here is a quote from Wikipedia:

Measurement Methods
The most common type of octane rating worldwide is the Research Octane Number (RON). RON is determined by running the fuel in a test engine with a variable compression ratio under controlled conditions, and comparing the results with those for mixtures of iso-octane and n-heptane.
There is another type of octane rating, called Motor Octane Number (MON) or the aviation lean octane rating, 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 rating, shown on the pump, is the RON, but in the United States, Canada 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 8 to 10 point difference noted above, the octane shown in the United States is 4 to 5 points lower than the same fuel elsewhere: 87 octane fuel, the "regular" gasoline in the US and Canada, is 91-92 in Europe. However most European pumps deliver 95 (RON) as "regular", equivalent to 90-91 US (R+M)/2, and some even deliver 98 (RON) or 100 (RON).[citation needed]
It is possible for a fuel to have a RON greater than 100, because iso-octane is not the most knock-resistant substance available. Racing fuels, AvGas, LPG, and alcohol fuels such as methanol or ethanol can have octane ratings of 110 or significantly higher - ethanol's RON is 129 (MON 102, AKI 116). Typical "octane booster" gasoline additives include tetra-ethyl lead, MTBE and toluene. Tetra-ethyl lead (the additive used in leaded gasoline) is easily decomposed to its component radicals, which react with the radicals from the fuel and oxygen that start the combustion, thereby delaying ignition, leading to an increased octane number.

[etepesq]

cheap gas

I'll try 89 instead but from shell and see what happens... perhaps you are right.
I do know that Arco sucks. I can hear something that sounds like knocking to me, their 89 and even when I use Arco premium. I stay clear now.
BTW... the guy that told me has a father that a is a senior very well respected bike mechanic in Seattle that has a pile of Suzuki mechanics award plaques in his now independent shop. I will put this question to his son regarding stock compression bikes, and Max octane.

Pete

[etepesq]

also

RE: "I thought i recently read a thread where somone found info that lead to the idea that using high octanes can actually cause pre-ignition and piston holeing. I dunno for sure"

It has always been my understanding that higher octane gas was actually less flammable (more stable) so that when you have higher compression it doesn't detonate early. I always thought low octane was more prone to pre-detonate/less stable??????
anyone????? Bueller????