Regular 87 gas with ethanol or Supreme 91

[87gtNOS]

I noticed in Wisconsin a couple summers ago as I rode the Harley to Sturgis, there were a couple stations that had pumps that had no ethanol, but had a silly warning label saying something like "for OFFROAD use only, not permitted in vehicles"....or something like that....

 

[airboss]

My practice is to use non-Ethanol fuel only. So if I can get the 87/Regular non-E fuel fine. If not, then I will go with the 91/Premium grade, which is (so far) Ethanol free. A few years back, I worked on a project where we were setting parameters for our department's marine assets. I came across a provincial government memo directing their departments, who used seasonal equipment, to use 91/Premium (non-ethanol) fuel exclusively.

 

[YammyRX1]

As others have mentioned run the 87 because the motor is tuned for that and will actually run worse with higher octane. Use a stabilizer like Seafoam with the 87 and then use the 91 for first run of the season and for storage.

 

[theCATman]

.

 

[theCATman]

I noticed in Wisconsin a couple summers ago as I rode the Harley to Sturgis, there were a couple stations that had pumps that had no ethanol, but had a silly warning label saying something like "for OFFROAD use only, not permitted in vehicles"....or something like that....

That was the diesel pump.

Seriously though, I run 89 in my Apex & Vector. I know Yamaha says 87 is fine, but being a motorhead, I know how fast things can go bad with detonation. I figure a little extra money for gas that gives some cushion is well spent.

With no knock sensor & an engine that sees high loads & spins 8-10,000 RPMS a lot, I want some wiggle room.

 

[BADSLED]

My uncles Apex suffered greatly with not running as well as it used to. So much so, that he considered trading it for a newer one. One day, I filled his with 91 NON-ethanol , same what I use for my Turbo Nytro and the sled came back to life. Yes, we believed 87 was the way to go but in all honesty I am a firm believer with increased ethanol content is closer to 20% desprite 10% claims these days. My suggestion is stick with 91 octane.

 

[vetcorman05]

As others have mentioned run the 87 because the motor is tuned for that and will actually run worse with higher octane. Use a stabilizer like Seafoam with the 87 and then use the 91 for first run of the season and for storage.

Run worse with the higher octane...... Since when?

 

[titanrcr]

Run worse with the higher octane...... Since when?

Shouldn't run worse but can make less power on higher octane than it's designed to run on.

 

[vetcorman05]

Shouldn't run worse but can make less power on higher octane than it's designed to run on.

Never heard of that.

 

[vetcorman05]

I don't think this started as a which fuel makes more power,I don't use non oxy fuel for any kind of power increase,I use it because it is,imp,better fuel period.

 

[titanrcr]

Never heard of that.

Yup, most people assume more octane more power. Not so.

 

[vetcorman05]

And it won't eat your hoses and wreck your carbs if it sits to long.

 

[YammyRX1]

Check Sasquatch's post #35 from the link below for a good explanation of octane:

"As a motor is tuned to fire the plug at so many degrees before top dead center. The amount is based on how long it takes for the fuel to ignite. The timing is figured out so as to have maximum push on the piston on its downward stroke. If the motor is designed to run with 87 and you put 91 in which is a slower burning fuel, the fuel burn and expansion of the gas happens later in the pistons downward stroke giving less push on the piston. So slower burning fuel can give less power and increase fuel consumsion because of wasted energy. This is more likely to make the sled slower. It also can make for a less complete burn and therefore can leave unburnt gasses behind which is the opposite of a cleaner burn. Will you hurt the motor burning higher octane? Not really, worst is maybe a bit more soot build up. However there is no benefit in it! I do however run my tank in my old warrior dry (or siphon it out) and fill with premium on my last run as that is what will be in it for the summer. Don't want to leave it with ethonal crap for the off season. Same as all my small motors such as lawnmower, snowblower, wood splitter, chainsaw etc.
Now lets explain what happens if you run a lower octane fuel fuel in something designed for a higher octane. If the fuel has a quicker burn then what the motor is timed for then the expansion of gasses happens before the piston reached its optimal point for maximum push and can even work against it, as in the piston is still going up (compression stroke) while the gases are expanding. Preignition can be a very bad thing. The new 11 up's however have a knock sensor to reduce ignition timing to prevent damage. I burn premium in my 11 everywhere I can. I will fill with regular if that is all there is but refrain from full throttle just to feel safer about it. Next tank is premium again so in theory half tank of premium mixed with regular is still higher at maybe 89 octane, then half tank of 89 filled with premium makes 90 octane. I have had no issues and heard of none doing this.
Anyway my two cents!"

http://www.ty4stroke.com/threads/switching-to-an-apex.128465/page-3#post-1154956

 

[titanrcr]

Yup, most people assume more octane more power. Not so.

Yes, ethanol is no good. Better to run higher octane and without the ethanol

Check Sasquatch's post #35 from the link below for a good explanation of octane:

"As a motor is tuned to fire the plug at so many degrees before top dead center. The amount is based on how long it takes for the fuel to ignite. The timing is figured out so as to have maximum push on the piston on its downward stroke. If the motor is designed to run with 87 and you put 91 in which is a slower burning fuel, the fuel burn and expansion of the gas happens later in the pistons downward stroke giving less push on the piston. So slower burning fuel can give less power and increase fuel consumsion because of wasted energy. This is more likely to make the sled slower. It also can make for a less complete burn and therefore can leave unburnt gasses behind which is the opposite of a cleaner burn. Will you hurt the motor burning higher octane? Not really, worst is maybe a bit more soot build up. However there is no benefit in it! I do however run my tank in my old warrior dry (or siphon it out) and fill with premium on my last run as that is what will be in it for the summer. Don't want to leave it with ethonal crap for the off season. Same as all my small motors such as lawnmower, snowblower, wood splitter, chainsaw etc.
Now lets explain what happens if you run a lower octane fuel fuel in something designed for a higher octane. If the fuel has a quicker burn then what the motor is timed for then the expansion of gasses happens before the piston reached its optimal point for maximum push and can even work against it, as in the piston is still going up (compression stroke) while the gases are expanding. Preignition can be a very bad thing. The new 11 up's however have a knock sensor to reduce ignition timing to prevent damage. I burn premium in my 11 everywhere I can. I will fill with regular if that is all there is but refrain from full throttle just to feel safer about it. Next tank is premium again so in theory half tank of premium mixed with regular is still higher at maybe 89 octane, then half tank of 89 filled with premium makes 90 octane. I have had no issues and heard of none doing this.
Anyway my two cents!"

http://www.ty4stroke.com/threads/switching-to-an-apex.128465/page-3#post-1154956

Perfect explanation!!

 

[vetcorman05]

It turns out that heptane handles compression very poorly. Compress it just a little and it ignites spontaneously. Octane handles compression very well -- you can compress it a lot and nothing happens. Eighty-seven-octane gasoline is gasoline that contains 87-percent octane and 13-percent heptane (or some other combination of fuels that has the same performance of the 87/13 combination of octane/heptane). It spontaneously ignites at a given compression level, and can only be used in engines that do not exceed that compression ratio.