hey, this has probably been asked a million times, but i didn't find it on a search...

i have always heard to use the highest octane gas you can, at least 91. but my owners manual and HD repair manual both say that 87 is ok. what do you guys use?

 

I'd like to hear what others use too..

I mostly use 89...rarely put in 91+...the few times I used 87 the bike felt sluggish.
I have stock engine/carb.

Edit:

You can check out this survey:
https://www.hdforums.com/m_90510/tm.htm

 

Mine has 10-1 compression and a ev-27, I need to use the highest octane available or I get more pinging. We also have a Buell Blast that will burn regular OK but I found I get about about 60 mpg (normal riding) with higher octane and get about 55 mpg with regular. I was always told that if you do not have a problem with pinging you are OK.

 

Original Evo compression ratio was 8.5:1, a half point higher than the standard 8:1 for regular gas. The higher octane is needed to prevent pinging or detonation. Higher octane resists compression detonation, so that detonation only occurs when the spark plug ignites the mixture. Over time, an HD engine will carbon up in the combustion chamber due to rich mixture and oil burning. The carbon layer in the combustion chamber reduces the size of the chamber and the compression ratio gets higher, requiring a higher octane gas. I have 170 lbscold cranking pressure (CCP) with an EV-27, a Cometic .030 head gasket and some carbon build up. I alternately fill up with 89 and 91.

 

I normally fill up with 89 but my buds all use 91 on there big 96s. I tried 87 once or twice but went back to 89. I plan on trying 91 also but
with the price going up quickly, I might not. I also have some octane booster that I received from J&P Cycles that I plan on trying to see if
it makes a difference.

 

I run regular unleaded in my 98 Fatboy. Around here its about 85 octane. I've never had a problem with it. My bike is cam'd and has a stage I with pipes and has been re-jetted. It runs great and I've had no performance problems. I say if you run regular and you get no ping or performance issues run that.
My 07 Roadglide however, if I go below 87 pings like a bastard.

 

I've never used anything but 87, and 85 in higher elevations, with nary a ping. Mine's got 130K plus, with an EV13 cam. Higher octane gas will not do one thing to improve your bike's performance if it has stock compression.

 

87 octain for 22 years. never been apart.

 

I mainly use 87 octane....

If the bike does not ping with 87....you are alright. A little ping from taking off is alright as well. If the bike pings all the time while normal riding....don't just start using higher octane. Instead, check the bike out for other possible problems. Higher octane might just be a band-aid for a solution.