I always put 91 Octane gas (highest Octane you can get in Socialist California) in my beloved Harley simply because I want the best for it. The cost difference is a couple of cans of beer; no big deal (at least until I retire).

I live and ride almost entirely on the Coast, at exactly Sea Level, give or take a few hundred feet.

So is there really any point in putting in 91 over 87? I had always thought that more Octane equates to more zippity do-dah in the gas. However, reading up on the subject it appears that the real difference has do do with pre-ignition, which is generally a non-issue at sea level. (?).

A related question. Thanks to our idiot Leaders, gas has that crappy corn alcohol in it, which is bad for all engines. Will 91 tend to have less of that?

Comments appreciated.

 

It sounds like it would be best for you to move to Mississippi or South Carolina. You might be happier! LOL!

 

Upwards of 97% of gasoline available in the US today has some level of ethanol in it. The most common blend is E10 and is absolutely fine to run in any relatively new equipment. Commonly the issue with ethanol is its short shelf life. Untreated, ethanol blended gas can begin to deteriorate in as little as 30 to 45 days. That can create gum & varnish over time.

Another problem is ethanol's stronger attraction to water than to gas. When as little as 4 teaspoons of water per gallon of gas is absorbed, you can get what is called phase separation. You are then left with the gasoline on top and a water/ethanol mixture on bottom (think Italian dressing).

At the end of the day, most of the issues you hear about with ethanol can be handled with proper fuel management. Being aware of how long it takes to run through gas and trying to keep the fuel tank full when sitting for extended periods of time will certainly go a long way in preventing headaches with your fuel system.

Have a great day!

 

Higher octane doesn't make the gas "better", the gas itself has absolutely no more power. The octane rating simply determines how resistant the fuel is to pre ignition. I too use premium in my Limited, mainly because that is what the MOCO recommends for it.

Don't know how things are in California, but here in the corn belt our gas all has at least 10% ethanol, has for several decades. That is true for all "grades"- regular, mid and premium. Except where ethanol free fuel is sold- I've only seen ethanol free premium, not sure if the lower octane fuels in MN are offerend ethonol free, I've not see any.

Most if not all engines made in the past couple decades are compatible with gas containing up to 10% ethanol. I'd assume that's what your premium has, unless the pump is labeled otherwise. If the gas has more than 10%, I'd hope the pump would state that, because you don't want to use anything higher than E10 in any engine that isn't rated as flex fuel compatible. Here we can get E15 and E85 at some places, but the pumps are marked, and if you put E85 in a vehicle not rated to burn the stuff, you'll have some trouble on your hands.

 

This is all absolutely correct! Any pump that has higher than E10 should be labeled as such as E15 is still generally not recommended for marine equipment, small engine equipment or cars older than 2001.

Have a great day!

 

Except for the first few months of 2013, I haven't put anything but regular in my bikes since then. No loss of power or pinging.

 

Great info, folks. Thank you very much.

 

Here's a simple rule:
If it pings on 87 run 91.
You're welcome.

 

87 will do the job just fine, your bike will tell you if it don't like it.

 

You do know that with lower compression engines you can get more power with lower octane gasoline due to lower vapor pressure.