I've been running 87 octane ethanol free pure gas in both my FI and carb bikes for quite some time now with zero issues. Never seen the need for the high test in these bikes.

 

from your signature, it doesn't sound like you've done any 'radical' engine work to your bike. since your bike was designed to run on 91, you shouldn't have any problem using it. I wonder if you can even tell the difference between 91 and 93?

 

I have used E10 87 octane since my first H-D in 06. Since then I have had every version of the twin cam including the 120's. All have run perfect on E10 87 (85 in the mountains)

Unless you have a built engine the stock HD runs regular with ease.

I manage to get 50 mpg out of them with the regular gas. Why waste money?

 

The 93 octane gas will definitely improve your bike's performance - no question. The 93 octane fuel has been strategically formulated to lighten your wallet which improves your power to weight ratio.

 

All-electric vehicles are increasing in popularity from west to east. As such, the western states are phasing out gasoline beginning with the highest octane first.

 

TBH...I've rarely seen 93. You'll fine fine. You won't need any "boosters" those have been squashed as headlight fluid a while ago.

 

They grow lots of corn, in those areas. Corn = Ethanol

Plus, lots of farm equipment around that doesn't need high octane, or high priced gas.

The high octane stuff would sit in the tank until it's gone bad, anyway.

By some octane booster, and ride on.

 

An engine's octane level to prevent pinging depends on its dynamic compression ratio. As elevation increases, air pressure is lower and so less air gets into the cylinders. That lowers the dynamic CR. So, less octane is needed to prevent pinging. Since less air is entering, the injection system will lower the amount of fuel as well to maintain the AFR. So the engine will produce less power. Increasing the octane will not have any affect on that. Note that if your MAP sensor is not working properly you'll likely have some problems.

 

In Maine there is only 1 gas station in the entire state that has 93 octane. You can find some 91's but the rest are 87 and 89.

 

Since I asked the question, it seems many have jumped to the conclusion that I'm worried about not finding high octane fuel out west. That's absolutely untrue. I've used 87 octane several times above 6000 feet (fully loaded) with no discernible difference in performance. I was just curious, and wondered if anyone knew the reason.

If the altitude of the western states is the reason for only finding 89 or less octane, it would stand to reason that cities near sea level, such as Seattle, Olympia, Seaside, San Francisco, Long Beach, Santa Barbara, etc., would have the higher octane fuel available again. Is that true? I haven't been further west that central Washington. Also, we normally have 91 & 93 octane available everywhere at 700' MSL in my local area.