I use 87 for daily commute, and on long fast trips, I put 91/93 for performance and cleaning any impurities in the engine.

 

so many fuel threads ive read in my life... 93 for me, no complaints. costs about 10 cents more per gallon than 87. SO WHAT

 

If I had access to a dyno, I would love to put this to rest once and for all. One run at the octain level speced by honda (87 for most) andone run at 93. ButI don't...

 

I've done it... but some still don't listen. But I guess higher octane = lighter wallet = faster bike in some peoples minds. Or you get the "it has more detergents or cleaners in it" B.S.


Here's what I wrote up on another forum. Why I never posted it here don't know...

When I had my 03 race bike, I spent a day on the dyno doing some quick "what-if" tuning with my engine tuner...
2003 Stock motor W/ slip-on, race filter.
87 pump = Just under 99hp
90 pump = Just over 98hp
92 pump = Just under 97hp
100 "pump race" = just under 98hp.
U4 race gas (92 octane) = Just over 100hp

So with a stock engine (internals) running an oxygenated race gas (U4) only gave a bit more than 1 hp over 87 pump. Just running AV gas or high octance "pump" race gas even when mapped actaully lost a bit of power. After I added a full system and got it custom mapped I was consistanly getting around 2hp more over 87 pump. So that helped a bit but not much.

But on my 2005 race bike with a "suspersport" built motor, and all the bolt on goodies. I'm seeing a difference of about 4 hp between 92 pump (That's the lowest I can run becuase of the supersport motor work) and U4. The only place I really notice the difference (on the lamp timer) is at tracks with really LONG straights and losts of WFO throttle, like Road America. At smaller tracks there is no real difference that I've noticed, by my butt dyno or the lap times.

 

So you actually are losing small fractions of power changing octanes, factory spec is 87, and gas is $3+ a gallon... i think the answer is pretty clear and has been most of the time....

 

Pop quiz hot shot-I was almost out of gas and had to use (big gasp) 86 octane from this little *****y country store. I only put in about a gallon and a half. 91 is the highest we can get around here. I still had about a half gallon or so of 91, is this going to have any long or short term effects. On the way home i couldn't tell any difference at speeds at or maybe a little above the posted speed limit. So any answers? nitwit out.

 

I have heard both arguements for sometime. I've used from Regular thru Premium & didn't see any major difference. So I primarily use Mid (89) & Premium on track days.

 

No Problems.

Guess how gas stations with three octanes of gas get the middle octane with only 2 holding tanks... Yep, they mix the lower octane with the high octane.

 

So many wives tales and theories on here. Use what the manual recommends. If the manual says regular unleaded and you use premium, you are only giving the oil criminals more money.That is because the engine is designed and built for regular and nothing higher makes any difference at all. It is afact of engine design. Don't listen to these guys here, they are like people who buy4 wheel drive trucks that never leave thestreet.

 

What you said is not completely true. Mixing some castor based synthetic oils with ANY other oil, non castor based synthetic or dino oil can cause a reaction with the castor which can gum up the works a bit.

There are still a few castor based synthetics out there. I used one in my KTM dirtbike for a while.