Octane? Really?
Thread Starter
|
Ultimate HDF Member
Joined: Sep 2007
Posts: 8,831
Likes: 15
From: Nomad
Octane? Really?
Kind of a dumb question, and I think I know the answer, but I'd like to hear your thoughts.
So, here in Montana, we're at altitude. Not crazy high like Colorado, but high enough, I guess, that gas sold here is not at the normal sea level octanes (87, 89, 93) but the high-altitude versions (85.5, 88, 91). I'm told that is to compensate for the thinner air. So I always put in 91 octane in my bike. Always runs fine.
But I was at a gas station where they had the sea-level octanes. So I thought, 'Heck, I'll try the 93.'
Every since then, my bike has been idling ROUGH, especially when cold. And it will even stall at idle. Have to give it more throttle than normal when letting the clutch out, too.
I know octane is all about the timing and compression, but could it have that much difference?
So, here in Montana, we're at altitude. Not crazy high like Colorado, but high enough, I guess, that gas sold here is not at the normal sea level octanes (87, 89, 93) but the high-altitude versions (85.5, 88, 91). I'm told that is to compensate for the thinner air. So I always put in 91 octane in my bike. Always runs fine.
But I was at a gas station where they had the sea-level octanes. So I thought, 'Heck, I'll try the 93.'
Every since then, my bike has been idling ROUGH, especially when cold. And it will even stall at idle. Have to give it more throttle than normal when letting the clutch out, too.
I know octane is all about the timing and compression, but could it have that much difference?
Elite HDF Member
Joined: Aug 2006
Posts: 3,871
Likes: 4
bad gas i run 91 or 92 and have had to run 89 when on a trip, and thats all they had never had any problems, my son is cheap and runs the cheapest gas they have i think 85 or so and bike runs great so go figure
Trending Topics
Extreme HDF Member
Joined: Dec 2007
Posts: 13,402
Likes: 941
From: Illinois
Run the lowest octane that your motor will tolerate. If you are not accellerating hard and don't lug the motor 87 octane will do fine. It fires easier and gives more mpg.
Many confuse octane with power. The octane rating is only to indicate the resistance to igniting and all octanes yield the same power.
Many confuse octane with power. The octane rating is only to indicate the resistance to igniting and all octanes yield the same power.
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
10 Motorcycles You Should Never Buy
Joe Kucinski
10 Things Harley-Davidson Needs to Fix in 2026
Verdad Gallardo
Southpaw Super Glide: A Left-Hand-Drive 1979 Harley FXE Built to Fit the Rider
Verdad Gallardo
The Best and Worst Harley-Davidson Moves of 2025
Verdad Gallardo
Road Master
Joined: Nov 2009
Posts: 1,063
Likes: 2
From: Palm Bay Florida
Did you ride down to sea level or trailer the bike? Is your bike fuel injected? The reason I ask is I had a customer tow there car from Colorado to Florida when they unloaded it from the the trailer car would not run because the computer was still thinking it was at 5000 ft in thin air took some time to relearn fuel ratios but if driven would have learned on the fly so to speak.
Thread Starter
|
Ultimate HDF Member
Joined: Sep 2007
Posts: 8,831
Likes: 15
From: Nomad
Did you ride down to sea level or trailer the bike? Is your bike fuel injected? The reason I ask is I had a customer tow there car from Colorado to Florida when they unloaded it from the the trailer car would not run because the computer was still thinking it was at 5000 ft in thin air took some time to relearn fuel ratios but if driven would have learned on the fly so to speak.