octane question
Road Warrior
Joined: Sep 2008
Posts: 1,620
Likes: 0
From: Irvine, Orange County, Ca
I use to think it really didn't matter since I'm able to get away with lower octane in my 300C when I have to. That was until I actually was forced to run 87 on the Laughlin River Run. There's a station out at the 62/95 that only sells 87. It couldn't have been but 2 minutes after filling up that the bike was wincing and sounding terrible. I now carry octane booster on my River runs. Bike runs great on 91 (as recommended by HD) so why screw with it.
octane ?
89 is fine here in SW MI, but when the temps get up to 85-90 which is never
then I might put in some 91. I know HD says 91 recomened, but they have an interest in shell brand. Most stations have went to single line pumps and 85% of todays cars run 87, so unless you can get in line behind a Premium user, the first .5 are what was pumped last. 
If it ani't knocking/pinging why waste your $$$.
then I might put in some 91. I know HD says 91 recomened, but they have an interest in shell brand. Most stations have went to single line pumps and 85% of todays cars run 87, so unless you can get in line behind a Premium user, the first .5 are what was pumped last. If it ani't knocking/pinging why waste your $$$.JMHO
Last edited by Willie D; Apr 24, 2011 at 08:24 PM. Reason: Sp
Tourer
Joined: Oct 2009
Posts: 325
Likes: 1
From: missouri
After a little googlin' I guess the general consensus is to never put fuel in your bike that contains over 10% ethanol. Interestingly, it is illegal for airplanes to use fuel that contains ANY ethanol. I like my bike as much as any airplane lol.
Advanced
Joined: Mar 2011
Posts: 50
Likes: 9
Only 93 I delivered fuel for a short time and most fuel farms leave it up to the drivers to mix 93 and 87 to come up with 89 and 91 I saw who delivers the gas and don't think I would trust to many of them doing the math 
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Club Member
Joined: Jul 2007
Posts: 463
Likes: 1
From: in a trailer next to a ditch in South Florida
I use 91-93......because the manual says 91 min. but I have a freind that races cars and he can't understand why the min octane is so high. The compression ration of the 96 cu in displacement engine is 9.2-1 which isn't really that high. Anyone know why HD requires 91 min.....is it for a longer burn?
1. cylinder head temperatures at low speed in hot weather,
2. compression ratio (which tends to increase as deposits build up in the combustion chamber over time) and
3. the stock ignition advance curve.
