93 octane only in buddys 1500 road king. its like a $1 more a gal than the cheap 87. bike runs so much better. cheap gas will make bike fart some times.

 

91 in CA

 

Try each of them and see if you can get any benefit. Way back we used to be able to get over 100 octane and one of my bikes absolutely flew on the stuff. Made choosing fuel very easy at the time! You may find that yours runs much better with a slightly higher octane.

 

I'm pretty certain you have a carb on that. We have a stock '96 1200C that we put 87 in. Seems weird to me, however my understanding (but I am not the expert) is that running higher octane in those runs 'em hot (language I often hear is "burns 'em up, and doesn't net you anything" -so don't do it).

I have also been advised to avoid plant-based gas (ethanol), because of the inefficient way it burns -but there may be more to it than that.

Just my 2-sense. Hopefully someone more knowledgeable will chime in.

edit: I came late to the party, so perhaps this has been discussed further back in the thread?

edit2: after some rabbit holing a bit... I think the idea that higher octane is going to "run'em hot" is misguided. I will post something up ahead.

 

Rotate between 89 & 93.
No 91 available in our local area.

 

I have been using 91 octane 100% gasoline (non ethanol) since I bought the bike, except twice I needed gas and bought 91 octane WITH ethanol.
The engine seemed to run about the same and no complaints.

I found out now that one station I go to also has 100% 87 octane (20 cents less per gallon) . . . no ethanol. Even though MoCo says run 91, I am tempted to try is since it costs less.
My neighbor has been running 87 with ethanol in his 2006 Sportster for 3 years now and says it runs fine on it. So. . . now what to do?

 

I run regular non ethanol. if I cant get that I run the middle of the road E10. Its an 883 carb bike so I trust the engineers...

 

Just for the record (and like I said, it may have been posted already) -but for the fella askin' about his '97 sportster...

I mis-spoke earlier... What I had been told was cautionary regarding carbon build up, not running hotter (which typically comes with running leaner, not fatter [du-oh]).

Amoung lots of of other fodder I stumbled upon, I found the following 2 discussions very interesting, so I am sharing them here:

(Delboy's garage is a celebrated street-authoritative resource.)

http://xlforum.net/vbportal/forums/s....php?t=1509599
(This is a very interesting discussion, even for the carb-sporties crowd.)


I'm inclined to run lower (87-89) octane, as specified in the manual, for my stock sportsters (a 95 and a 96) until/unless I observe pinging, detonation, or it 'feels' like it needs more (hot summer riding).
However, after listening to what Delboy had to say, I would be inclined to run a tad higher without worrying about it (carbon buildup concerns), and see if there's any benefit. (I think checking your plugs will help you out determining if your running too rich.)

It seems its generally recommended to consider adjusting higher oct as you upgrade your bike.

For the record:
...my '86-'03 manual states: "...recommended pump octane number is 89 or higher for 1986-1990 models and 87 or higher for 1991-2003 models..."

"...DO NOT use gasoline containing methanol (methyl or wood alcohol).
...DO NOT use gasoline containing more than 10% of ethanol (ethyl or grain alcohol).Too low octane will result in ping or knock."

Cheers,
HTH

 

93 octane here.

 

This fellow says to use the highest octane you can to cool the engine.

I am not so sure this is correct for the closed loop EFI systems. It is my understanding that the afr stochiometric point decreases with increasing octane. If the stocih point decreases (to say 14.2) and you ECM is still calibrated to afr=14.6 in closed loop then I think that the bike will run leaner on the higher octane gas, meaning it will run hotter. In order to get the benefit of the higher octane fuel, we would have to be able to edit the stochiometric point set in the ECM to the new value, 14.2.

OTOH, I ran across this post. The fellow says that when he used high octane fuel with his stock heads(not on a harley) the bike ran richer. The reason given was that the higher octane fuel burns slower so all the fuel may not burn during combustion phase, leaving free fuel in the exhaust. If that is true then our closed loop efi will detect a rich condition and try to reduce the amount of fuel.

Frankly, I really do not know what would happen if we used an octane booster in our closed loop efi bikes.

http://motoredbikes.com/threads/does...erature.24589/