Does anyone run 87 octane gas on your ST1100, and is it ok.
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.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.
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
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.How about ethanol, are you running E10 in your ST1100 or filling up at the few (and sometimes far apart) non-ethanol pumps?