Fuel type for the XS1100 special

[OldGreyBeast]

I've done some searching but surprisingly didn't find a lot of threads on this. My bike's side cover says to run 91 octane. I generally like to run ethanol free in my vintage bikes, however I can only get ethanol free in 87 octane. I definitely don't want the bike to ping or blow a hole in a piston, am I stuck with running ethanol fuel or is it ok to run 87?

[Schming]

ETHANOL FREE !!! octane doesn't matter all that much

[DEEBS11]

Ethanol free fuel is great if you can get it. I run pump gas with the standard (here in Connecticut) 10% Ethanol. I agree that octane does not seem to matter. I have never had any issues. Many hundreds of thousands of miles covered. However, don't use gas with more than 10% Ethanol.

[OldGreyBeast]

Ethanol free is what I was leaning towards, good to know that the octane level doesn't seem to matter too much for these guys.

[DiverRay]

The bikes WERE designed to run REGULAR GRADE gas. If you run premium, you will carbon up the inside of the engine. If you have put a big bore kit, and the compression has gone up, then you could run premium.
With that said, I run regular grade ethanol free gas in my Special with no problems. and I do think it had a big bore kit installed, I've just never had the head off to see.

[LAB3]

With the way I travel searching for, finding and paying for ethanol free doesn't make much sense. I run plain ole 87 octane regular and will occasionally get some pinging at low RPM (65-70) highway speeds, I kick it down to 4th and it goes away. I've never had problems running it in any of my bikes, not sure why people seem to have such a bad attitude toward it.

[speedlimit85]

mine will ping with 87, goes away with 89

However, with non- ethanol runs great with 87 89 90

[Ccitis]

Sadly, many of us cannot find ethanol free anymore. It is gone.... not much we can do about that.

[DEEBS11]

It's very rare here in the Northeast. I did see some out west once. 15% (ethanol) should be avoided totally for all older machines of any type including lawn mowers.

[Bonz]

mine will ping with 87, goes away with 89

However, with non- ethanol runs great with 87 89 90

Sounds like 87 octane with 10% ethanol pings whereas 89 with ethanol doesn't ping? My 80 SG didn't ping on 85 octane 10% here in colorado. That is our regular.

That's the first time I've heard mention of ethanol versus non-ethanol making a difference in octane needed for an XS1100. Not doubting it, but seems rather irregular based on the whole of XS1100 experiences.