Does anyone run 87 octane gas on your ST1100, and is it ok.
87 Octane gas for ST1100
- Thread starter kjkst1300
- Start date
DJDixon
Site Supporter
I run regular in my '02 ST1100 without any issues. On my '97 ST1100A, it would lightly ping with regular under hard acceleration if the weather was hot, so I used to run mid-grade gas instead. There are some manufacturing variances from bike to bike, if it doesn't ping regular is fine.
I did try one tank of mid-grade in the '02, there wasn't any power difference or running difference so I went back to regular. The ST1100 is rated for regular fuel.
I did try one tank of mid-grade in the '02, there wasn't any power difference or running difference so I went back to regular. The ST1100 is rated for regular fuel.
+1 on everything Don said.
Mine is a 1993. The repair manual say's 91 octane. I use 89, and tried 91 and 93 but felt no difference. I will give 87 a try.
Run 87octane fuel all 11 yrs. of ownership with never an issue......mostly LD rides
.
.
I use 87 quite a bit in my 1991 recently. My trips are usually along rural roads and many stations have been out of premium grades over the last year. Just got in the habit of using 87. I have noticed no difference in performance or mileage.
Here in CO your 87 is our 85. Been using it forever.
I've run 87 in two ST11s for about 90k miles over the past 4 years... no knocking, no apparent issues.
I've run 87 in one ST for the last 20 years, no problem. When I first bought the bike I ran a few tankfuls of 87 and 91 on my mostly freeway commute. If anything I got a few more miles out of the 87, which was consistent with other riders experience back in the old ST e-mail forum of that era.
Always 87, no problems.
In the States, an 87 AKI rating , which is the average of the RON & MON rating {( RON+MON)/2 , take a look on your gas pump } is equivalent to about a 91 RON rating in Europe.
My Owners Manual calls for 86 octane or higher., but doesn't specify which rating. I have used 87 ( R+M)/2 without any pinging. I have tried using 89 octane to see if my mileage would increase or if the bike would run "better" , but I didn't feel or measure any difference. In some locations, premium gas contains no ethanol, and since 89 is a blend of 87 & premium, 89 may contain less ethanol than 87 octane. That may be the only advantage in using other than 87. And since a higher octane rating burns slower than a higher octane rating, a motor designed to run on 87 octane may actually get lower gas mileage using a higher octane, some claim.
My Owners Manual calls for 86 octane or higher., but doesn't specify which rating. I have used 87 ( R+M)/2 without any pinging. I have tried using 89 octane to see if my mileage would increase or if the bike would run "better" , but I didn't feel or measure any difference. In some locations, premium gas contains no ethanol, and since 89 is a blend of 87 & premium, 89 may contain less ethanol than 87 octane. That may be the only advantage in using other than 87. And since a higher octane rating burns slower than a higher octane rating, a motor designed to run on 87 octane may actually get lower gas mileage using a higher octane, some claim.
Last edited:
Very true, the higher octane fuel ignition point is a tad higher, so it is a bit 'late' igniting timing wise. In other words, the high octane fuel can be required for engines having a 12:1 or 13:1 compression ratio. This higher compression ratio compresses cyl. fuel mixture tighter which creates heat in itself. In order to 'slow' that ignition point down a bit as far as ignition point or timing wise of igniting point, a slower igniting, higher octane fuel is required. Hope that explanation helped
. In other words, the 87octane fuel is fine for the ST11, where as the ST13 with its 13:1 compression ratio(IIRC) recommends premium fuel.
Last edited:
Uncle Phil
Site Supporter
87 in all three of my ST1100s for 300,000+ miles and no problems.
John OoSTerhuis
Life Is Good!
The ST1100 engine was designed for 87. Using fuel with a higher octane number is a waste of money. Putting in 91 is not “treating her to the good stuff!” A silly idea that’s long been debunked but stubornly persists. And when I’m at altitude and 85 is available I use that.
John
John
Last edited:
How about ethanol, are you running E10 in your ST1100 or filling up at the few (and sometimes far apart) non-ethanol pumps?
STraymond
Site Supporter
John -
Does the 85 octane help reduce ST1100 bogging at the higher altitudes?
Ray
I've not experienced any issues running 87 or 85 out west, nor have I had any issues running E10 although I "feel" better using fuel without the corn.
The only time I fill up with the high test stuff is before putting the bike to bed for the winter. Chevron Supreme (here in Canada), and I think Shell premium too, contains no ethanol and I prefer having that in there for five or six months, to prevent water separating out of the fuel over the winter. Plus I add some fuel stabilizer to the high test winter fill.
John OoSTerhuis
Life Is Good!
Here in the heartland it’s almost impossible to avoid 10%.
At altitude all three grades’ octane ratings are reduced by 2 (85, 87, 89), IINM you won’t find 91. I don’t know the science of it, but 85 at higher elevations is the functional equivalent of 87 at sea level as far as the ST1100 engine is concerned. I’ve never experienced pinging (detonation) on my ST.
We’ve got CV carbs. Climbing at 14,000 ft you will bog down in 5th. Downshift to get to the top of the pass. BTDT
Edit: ethanol free gas: https://www.pure-gas.org
John
At altitude all three grades’ octane ratings are reduced by 2 (85, 87, 89), IINM you won’t find 91. I don’t know the science of it, but 85 at higher elevations is the functional equivalent of 87 at sea level as far as the ST1100 engine is concerned. I’ve never experienced pinging (detonation) on my ST.
We’ve got CV carbs. Climbing at 14,000 ft you will bog down in 5th. Downshift to get to the top of the pass. BTDT
Edit: ethanol free gas: https://www.pure-gas.org
John
Last edited:
STraymond
Site Supporter
Here's what I found on using lower octane at higher altitudes:
"Air is thinner the higher above sea level you go. Less air going into the cylinders means less pressure at top dead center when things go bang. It's a lot like lowering the compression ratio in the engine, reducing the need for high octane. Cars will run just fine on lower-octane fuel when they're well above sea level-"
Ray
"Air is thinner the higher above sea level you go. Less air going into the cylinders means less pressure at top dead center when things go bang. It's a lot like lowering the compression ratio in the engine, reducing the need for high octane. Cars will run just fine on lower-octane fuel when they're well above sea level-"
Ray