Do you use premium gas in your Sportster?

[Tomcatt]

I run premium. There's a Mobil gas station "mart" about a mile from my house with 91 octane (M+R/2) no ethanol. I've been seeing some detonation, the ECU (with Powervision) has the detection software but oddly doesn't have the software to pull timing. So, I've been tailoring my fuel and timing mapping around knock indications. I expect the detonation to go away when I get the top end off and tighten up the squish clearances.

I went thru the same process on my BT Evo. It also had .055" head gaskets as OE. Harley made a running change to .040" head gaskets to tighten the squish clearance to fix the detonation issues the earlier BT EVO's had. I did more, also shortening the cylinders. Here I am 30+ yrs later doing the same the same thing on my '17 Evo Sportster. My BT EVO was an '87.

[boomerguy]

The owner's manual says premium gas for the 1200 and regular for the 883 because of the compression ratio for each.
I usually run mid-grade 90 octane because that's the only octane for my non-ethanol gas available locally. While traveling away from the house, I can run 87 in my 2005 XL883 with no problem.

[Tomcatt]

Originally Posted by boomerguy

I usually run mid-grade 90 octane because that's the only octane for my non-ethanol gas available locally.

I not a "never ethanol" guy. I run 91 octane no ethanol because the station conveniently near my house sells it. Their (Mobil) premium was 93 octane with ethanol previously and I ran that. Same station where I usually fill my daily driver with "may contain up to 10% ethanol" regular.

[boomerguy]

If I knew that I could ride my motorcycle daily like I do my cars, I wouldn't sweat the 10% ethanol gas because I know it would turn-over quickly in my tank.

However, my daily schedule and the fluctuating weather keep me from riding it as much as I would like to and it may sit for weeks or months at a time. So I keep a 5-gallon can of non-ethanol in the garage to top it off with after each ride. I would rather have it sit completely full of non-ethanol, just in case.

I also turn off the Golan manual petcock about 100 yards from my house so the carb will run empty when I park it in the garage. Probably overkill, but it's easy to do and it gives me peace of mind.

[Tomcatt]

Originally Posted by boomerguy

If I knew that I could ride my motorcycle daily like I do my cars, I wouldn't sweat the 10% ethanol gas because I know it would turn-over quickly in my tank.

I would rather have it sit completely full of non-ethanol, just in case.

I also turn off the Golan manual petcock about 100 yards from my house so the carb will run empty when I park it in the garage. Probably overkill, but it's easy to do and it gives me peace of mind.

That's edited but I hope not out of context. If you're not comfortable with the current ethanol added fuels that's your prerogative.

I traded in a 2002 Kawasaki Mean Streak (that I bought new in 2002) on my Sportster in Feb this year, 2019. It had 9.5:1 CR and ran on regular. It sat 17 winters, plus 2 summers I couldn't ride due to surgeries and chemo, with regular "with up to 10% ethanol" in its' (full) tank. When I traded it in it still had all its' original fuel system components, the tank had never been off to be cleaned, the fuel system (EFI) had never been apart. No problems, ever.

I could go on but that is typical of my experience with ethanol added fuels. Racing on 100% methanol (and setting up carbs and fuel systems to flow enough) is a more fun story.

[jcn59]

I find that if I use non-korn-likker gas in my bikes, boats, lawn mowers and atvs, that come spring, everything starts right up & runs fine with no curse words or other issues. (Northern WI) I haven't noticed any other advantage. I suppose that if I jacked up the timing I might need the premium gas, but I don't.