My usual theory is:

-it's not going to make it worse
-it will probably in the very long run help with engine quality
-there is probably no performance boost
-so if you feel like using it, use it.

Easiest way is to try the different levels of gas and determine for yourself. With my cars, I noticed a big difference in my Celica, not so much in my Jetta.

 

I typically run 87 on the street and 93 at the track. My truck runs on 93 so whatever I have left over in the cans I just dump into my truck.

 

The way a high octane can reduce performance in a vehicle is as follows...

Oil when refined or "cracked" seperates much like oil and vinger in a jar.


With oil it seperates out by the number of carbon atoms in the chain of compounds. (i.e. octane=8) The lower the carbon count the more volatile the fuel.(diesel has far more carbon atoms, propane has far less)

So the refiners mix the subtance octane with heptane to use the otherwise useless heptane. This is where the ratin partly comes from.(additives to reduce not has since added their influence to octane rating) The high the ratig the more resistant to ignition the fuel is.

So in simple terms it takes more spark/heat to ignite 93 octane vs 87.

So in a carbed bike with no ecu the bike may not ignite all the fuel causing back fires and dieseling after shut off.

That is fuel science in a nut shell

 

What's your take on ethanol?

 

I can't believe this is an argument. The engineers, ENGINEERS, say 86 or higher. If you have a degree equivalent to theirs or you manufacture your own motorcycles, I'd go with what those guys tell you.
You wont get better mpg's, you won't get more performance (unless you have some mods and a tune for them), you WILL have less $$ in your wallet.
Go with 87 oct, you'll be ok. Hasn't failed me yet.

 

I use 85 octane with up to 10% ethanol ~ no problemo. I don't ride slow either, lol.

Edit: But I'm picky about the brand; only Shell gasoline.

 

Ethanol simply put is great if you are in the business of growing sugercane.(you make lots of money)

In blends it does nothing more than reduce fuel economy.
This goes back to the previous post of reduced performance.

Ethanol has a much higher octane rating. For maximum efficency the compression in the engine would need to be much higher. (Like a diesel or alcohol burner race car)

Basicly ethanol blend is all politic with greater cost for the public with little to no enviromental benefit.

With out the proper engine tuning ie compression even the E85 vechiles require 50% more ethanol fuel than it would need if it were pure ethanol.

I prefer no ethanol because I see it as buying a soda at McD's and having the cup packed with ice.

 

Thats how I have always understood it. I guess the real reason I buy premium is actually because it is the only thing around here that doesnt have ethanol. And actually I forgot I use to put in 87 (no ethanol, Shell) gasoline because since it is used by more people, it will be the most fresh in the gas stations storage tanks. But then they all went to 10% ethanol except for premium. So Is is better to run fresher 87 w/ ethanol, or less fresh premium w/ no ethanol...or does it even really matter in a FI bike?

 

I think the difference is a wash between the two.

 

Holy Moly! There are still the same exact new threads since last time I visited here. lol I use the low grade gas.

Mike