Mine runs fine one mid grade during the winter, but as soon as the temps go above 60 deg I have to run super or she pings noticably. I'd hate to be stuck with only regular grade. But on most long trips I have my laptop any way, I'd just plug it in an using the PC III add fuel adn take away spark advance to save the engine.

Re'

 

Out in my neck of the woods, there a many stations that do not have anything but regular. (Vidal Junction comes to mind. Only gas in the middle of nowhere.) I just run it. Stay out of the throttle a bit and it isn't a problem.

 

I ran into a situation where the only station for miles had two types of fuel. Diesel, and 85 octane regular. I ran almost a tank of the regular and noticed a little hesitation and some ping under hard acceleration. I just stayed out of the throttle as much as I could. If I knew I was going to be in that situation again, I'd pack some octane boost, but I wouldn't hesitate to do it again if I needed to, without the boost.

 

I have had to burn regular a couple of times when gas was scarce such as during Katrina. It burned OK in my '08 RKC but it got poor gas mileage. Other than that, no noticeable difference. Of course it was only one tank at a time and never used unless out of necessity. Hope that helps answer your concern.

 

I run premium always, but have been on rides where stations didn't have it. Just put in a couple of gallons and kept going till I find one that does. No ping with the mix.

 

My manual calls for 91 Octane - this is not available in my area...

my only choices are 93, 89, and 87.

I am going with the 93 for now - hopefully, the extra octane won't hurt anything??? Or, should I just run 89???

Does the Harley ECM on a 2008 retard the timing to compensate for a lower octane fuel than the recommended?

 

thanks for articulating it better than I had.

I was/am cocerned that while riding the Hoka Hey Motorcle challenge, I may find myself in the far northwest in the wee hours of the morning and be forced to run regualer or nothing else. The analysis of the many responses is: yes you can run on regular if you must, but caution and due diligence is advised.

 

Of those three choices I would use the 93 octane as well. The manual calls for 91 octane and I wouldn't use anything below that unless I was out of gas and had no other choice. I would assume you are right at or just below sea level and that's why your premium gas is 93 instead of 91 like it is here but I could be wrong.

 

Just bring along octane boost. It's not that difficult to pack it among your stuff -

 

I have used regular several times and never had a problem on either Harley I have or have owned. Buddy of mine only runs regular in his '05 RG and has never had a problem and he has 30K on it from new. Might depend on how "quality" the regular is, how much water etc, and how you ride is tuned.