High octane

**blowerbike** · 04-29-2014, 02:29 PM

rob you are not loosing any power.
going from 86 to 93 octane IMO does not change your seat of the pants feel.
now if you buy "racing" gas aka 100 octane and up and if it's not needed it can take power away but....it smells sooooooooooo good

**Rob S.** · 04-29-2014, 02:42 PM

I've never used 86, always 92 or 93.

So theoretically, I could gain a miniscule amount of power by switching from 92 to 85?

What would you put in a relatively stock 1100EZ if you didn't pay for gas?

**srg** · 04-29-2014, 02:50 PM

Higher octane fuel is "harder" to burn than lower octane. In engines with high compression ratios, low octane fuel may explode prematurely. Using higher octane fuel prevents the premature burning (knocking).

I'm not entirely sure that it burns slower, but higher octane fuel can withstand higher compression without igniting.

Read this:

Octane rating - Wikipedia

https://en.m.wikipedia.org/wiki/Octane_rating

**Rob S.** · 04-29-2014, 03:07 PM

I've always believed that if you didn't hear any knocking with regular, premium was just a waste of money. Since I don't pay for gas, I always got premium. But if I'll theoretically gain a teensy amount of power with regular...

I might as well save someone a few pennies. Make my accountant proud.

**blowerbike** · 04-29-2014, 03:21 PM

you never really know what's coming out of the hose honestly...
i would just do as you have been doing but that's just my opinion.

**Rob S.** · 04-29-2014, 03:23 PM

Originally posted by blowerbike

you never really know what's coming out of the hose honestly...
i would just do as you have been doing but that's just my opinion.

Will do. I know someone who built a bike like yours knows more than I do.

**jbthomp** · 04-29-2014, 04:17 PM

IMO premium fuel is a ripoff anyway. Most people don't know what octane does anyway, they think high octane fuel makes their ride faster (it doesn't). High octane fuel just prevents detonation in forced induction or high compression engines.

**dorkburger** · 04-29-2014, 05:15 PM

In hot waether my 1150 will ping if I try to get away with even mid grade. Mainly under load, or a quick roll on the throttle, if passing for instance.

**GS1150Pilot** · 04-29-2014, 05:36 PM

Same here. I run premium during the spring and summer, mid-grade in fall and winter in my 1150.

**tkent02** · 04-29-2014, 05:37 PM

If your engine pings, knocks or detonates, try a higher grade. If it doesn't don't. Almost all of my GSes have been fine without it, a few have pinged once in a while in hot weather, so on that one I used better grade in Summertime. One of my buddy's GKs detonated constantly once warmed up, but it had something wrong with it, the Premium fuel didn't help it much if any. A big waste if it's not needed, and I believe it does lose a bit of power if the engine is built for, tuned for and runs fine on regular gas. I'm also quite sure any power losses are much to small to check with any butt dyno. And on an engine with a problem such as carboned up combustion chambers or advanced timing among others higer octane fuel can be an effective band-aid.

**srg** · 04-29-2014, 05:41 PM

Gasoline companies do have "winter blends" and "summer blends" too. The fuel you get in the winter is not the same fuel as you get in the summer, even if it's the same exact pump with the same octane rating.

**Guest** · 04-29-2014, 05:54 PM

Originally posted by srg

Gasoline companies do have "winter blends" and "summer blends" too. The fuel you get in the winter is not the same fuel as you get in the summer, even if it's the same exact pump with the same octane rating.

That was the case some years ago, though not sure it is now. The winter mixtures were ones with ethanol blended in, and switched in the summer to non blended gas. Now that 10% ethanol is in everything all the time, not sure we have those season blends anymore per se.