gasoline
Tourer
Joined: May 2007
Posts: 313
Likes: 3
From: UT
You should use higher octane when your compression is higher. Octane = resistance to burn. So while your cylinder is compressing your fuel mixer it won't ignite before your spark plug ignites it. Too low of octane fuel will ignite do to compression in higher compression engines before the plug ignites it. That creates pinging and knocking. When using higher octane fuel with compression below 10 to 1 might not completely burn so it will cause your engine to build up carbon because of unburnt fuel. So the answer is NO.
Ultimate HDF Member
Joined: Jan 2009
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From: East Tn Foot of The Dragon
2005RK
2007 Ultra
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Last edited by checkers; Jun 6, 2017 at 06:04 PM.
Road Warrior
Joined: Jul 2013
Posts: 1,649
Likes: 443
From: Indianapolis
The average engine will not see a significant a increase in performance difference between 89 and 91 octane but higher octane will will help with "pinging."
As compression increases so should the octane rating. Which is why NASCAR used 110 octane (but made a move to to E15 98 octane several years ago) Indy cars burn 113 octane but also using E15 fuels and Top Fuel uses nitromethane/methanol fuel.
As compression increases so should the octane rating. Which is why NASCAR used 110 octane (but made a move to to E15 98 octane several years ago) Indy cars burn 113 octane but also using E15 fuels and Top Fuel uses nitromethane/methanol fuel.
http://www.sunocoracefuels.com/fuel/e85-r
Please note that due to the high oxygenation of E85-R, the octane values are estimated.
Note: the octane ratings for E85-R are estimates. The conventional ASTM laboratory octane tests cannot accommodate the high oxygen content of fuels like E85-R.
Elite HDF Member
Joined: Mar 2014
Posts: 4,214
Likes: 661
From: Prior Lake, MN
My bike runs equally well on E10 as it does on E0. It's approved for up to E10, which is what most of our gas has, you have to seek out E0.
One place I fill up only offers E0 premium at their pumps, they dont' have E10 premium that I can see.
I can't tell the difference in performance, both fuels are rated 91 octane, or whatever the typical "Premium" octane rating is around here. I dont' track my MPG's very carefully, so I don't know how the E10 vs E0 thing impacts me. Doesn't appear to be too significant. I get in the Mid 40's mpg.
Seasoned HDF Member
Joined: Apr 2017
Posts: 9,603
Likes: 20,703
From: Globe AZ
I dont have access to ethanol free, so that is a moot point for me. I did however run my last tank as premium vs "regular" and the engine is definitely quieter, leading me to believe I was getting some "Bad" things happening (pinging or knocking). I didnt see any bad signs on my plugs, IE metal deposits, signs of overheating, etc, but given our ambient heat here in PHX is over 100 degrees, I will run premium for the summer to give the engine a fair shake on not getting damaged
Cruiser
Joined: Aug 2012
Posts: 169
Likes: 39
From: Peoria, IL
Road Warrior
Joined: Sep 2016
Posts: 1,385
Likes: 1,416
From: Northern NJ
Others have given the right answer: unless you have made mods to the engine that change the compression, it is best to use what the manufacturer recommends. Also, Use Top Tier rated gasoline. TopTier guarantees quality gasoline and a satisfactory additive package in all grades of the TopTier rated gasoline.
Road Captain
Joined: Sep 2005
Posts: 725
Likes: 33
From: East, TN
I get at least a 2mpg improvement with 93 oct real gas.
Last edited by rideflhr; Jun 3, 2017 at 12:45 PM.
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Club Member
Joined: Mar 2016
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From: Clearwater, Idaho
^^This.^^ I run ethanol free premium (91) almost all the time as it's easy to find where I live. The difference between it and 10% ethanol 91 octane is generally 2-3 mpg, and the bike clearly runs better and smoother as well. I won't run lower than 91 unless I need to fill up in a locale where 91 isn't available.
