Fuel

[cberkeley]

So which fuel is actually recommended for the GS ....Regular, Super or Premium?
Is there a noticeable difference?
Leaner? Richer? Cleaner? Power differences?
I've been running on Premium since I got the bike 13-months now.

[rphillips]

Not sure about yours, but as far as I can remember all U.S. were designed to run on regular (87 octane) pump gas. If your bike pings a little on that, go up to 89 octane.

[bonanzadave]

All our gas in MN is an ethanol blend. I try to use a pump at the co-op that is non-oxygenated premium for RVs, small engines and boats. The GS loves it. The nozzel is too big to fit in a car. Actually its illegal to use in a car. Today it was $2.60. The ethanol blended stuff is unstabil and really screws with carbs in as little as 2 months. I had a rough time with the boat last summer cause I stored it over winter with no fuel stabil in regular oxygenated fuel.

[earlfor]

As far as I know, all GS models were factory specified to be run on 87 octane gas with the exception of the 1150. Factory spec for it is 89 octane.

Earl

[rphillips]

Recken why 89 for the 1150's? best I can remember, the compression & ign. timing was the same for the 1150's & 1100 E's

[80GS1000]

Seat of the pants test tells me that there's more power to be had out of 92 octane gas, especially from the Chevron and Exxon brands. Would be interesting to put the bike on a dyno and see if it's just subjective or if there's an actual HP/torque to be gained from using higher octane gas from a given brand.

[marvinsc]

I Find that My 850 is Happiest With Midgrade (89 Octane) I had some Pinging with Regular Unleaded.

[Nessism]

Seat of the pants test tells me that there's more power to be had out of 92 octane gas, especially from the Chevron and Exxon brands. Would be interesting to put the bike on a dyno and see if it's just subjective or if there's an actual HP/torque to be gained from using higher octane gas from a given brand.

My understanding is that the only way to get more power out of Premium is to advance the timing to take advantage.

[Grandpa]

We've had this fuel discussion many times in the past.

I've been riding GS shafties for 250,000 miles since 1986. They've all run just fine on regular 87 octane, including my present GS1100GK. A long time ago I determined that premium doesn't make any difference in performance or mileage, so why spend the extra money and increase the oil companies' profit margin?

If your stock GS won't run properly on 87 octane, to me it's an indication that something is wrong with the bike, conceivably carbon deposits that change the compression ratio.

So, I run any brand of 87 that's available; after all, I'm a member of the "Between the Sheetz Gang".

[cberkeley]

Interesting info all. I've been wondering about this for sometime now and did not find anything on the subject, hence my asking.
I'm presently running premium now and will drop down to "super" and run on that for the next few weeks then down to "regular" and I will try to note any differences in performance "feel" and plug color. I agree "why increase the oil companies' profit margin".
I just sent an e-mail to our local gas company (National Petroleum) asking that they inform me as to the octane rating of the three available fuels here, as this info is not displayed at the gas-pumps and it's not on their websites either.

[denydog]

This is straight out of my owners manual.

"Use only unleaded or low-lead type gasoline of at least 85-95 pump octane (R+M/2 method) or 89 octane or higher rated by the Research method. If engine pinging is experienced, substitute another brand as there is a difference between brands.

Note: Unleaded and low-lead gasoline will extend spark plug life."

I discovered early on, when the bike was new, that it would ping slightly when the engine got very hot and was put under a heavy load (up hill in lower gears), so I've run premium ever since.

Every thing I've ever read says that unless you have a problem with pinging, higher octane gas has no special benefits and is a waste of money. There has been a persistent myth forever that higher octane gas is just inherently superior. But if you have the money and it makes you feel faster, then go for it!

[earlfor]

Recken why 89 for the 1150's? best I can remember, the compression & ign. timing was the same for the 1150's & 1100 E's

I dont know. I did try 87 octane in the 1150 and it runs fine on cooler days.
On a hot summer day, it will preignition ping on 87 but not on 89.

Earl

[chef1366]

I always run premium.
Why? Because it's there:-|

I always thought you had less carbon deposits on higher octane fuel. I don't know for sure though.

[Boondocks]

I always run premium.
Why? Because it's there:-|

I always thought you had less carbon deposits on higher octane fuel. I don't know for sure though.

No, this isn't true. On the other hand, if you do have significant carbon deposits, this can cause preignition. Preignition leads to detonation (pinging). Use of a higher octane gasoline can be useful in this case.

Quoted from Sportbike Performance Handbook by Kevin Cameron:

Octane number is a measure of a fuel's resistance to detonation. It is not a measure of the power of the fuel, or of its burning speed....

There is no benefit to using higher octane fuel in a GS motorcycle that is not pinging. Pump gasoline is inconsistent, and simply switching from one brand to another of the same octane rating can sometimes eliminate pinging. I always went out of my way to avoid gasahol (10% ethanol) blend until my bike starting pinging with the straight gasoline in hot weather. I tried a tankful of 87 octane gasahol and the pinging stopped immediately. Alcohol tends to increase the octane rating.

See A Consumer's Guide: Gasoline Octane For Cars.