Are you really buying 93Octane?

[Hawkeye]

So I assume most of you are buying 93 Octane or better to put in your scooters or other small engine vehicles.  When I get gas, I'm usually getting about 0.75-0.9 gallons, since my tank is only 1.3 gallons. So even though I'm selecting 93 octane at the pump, am I not actually just getting whatever gas the last guy selected that's still left in the hose? Am I actually even getting any 93 octane at all since I'm pumping such a small amount? Does anyone know a definite answer to this?

[Mr. Paul]

I buy the octane that is recommended for my scooter. I wouldn't worry too much about the fuel in the hose. A percentage of the time it is high octane from the previous motorist anyway. I guess that makes my average octane about 87.9. 

[Tromper]

On the bright side most Asian scooters use 93 RON which is 87 R+M/2 (AKI) so you're good to go.

Euro stuff is where you run into trouble since Euro regular is closer to U.S.  Premium.  The single hose setup is of most concern to them.  There have been some reports of ping.

I ran U.S. 87 in my S200 mostly, I went to higher octane in very hot weather on long runs since I did get some ping under those special circumstances.
I run 87 in both my SYMs, & run 87 in my burger, & it's predecessor, no issues save the occasional bad batch, & one year where the winter blend was exceptionally awful.

With the all scoots I grab no-eth when I can but that's a bit rare for me.

https://en.wikipedia.org/wiki/Octane_rating#Difference_between_RON.2C_MON.2C_and_AKI is a handy reference.

[Iahawk]

that is why I fill at stations that have pumps with dedicated hoses...not shared hoses among the different grades. I believe you are correct in that the hose is filled with whatever fuel the previous person purchased...and 99% of the time it will be the cheapest gas ( that's ethanol blend around here).

When I fill my gas can for my mower I first pump about a gallon or two into my van...then I fill my gas can...as I don't want the previous guy's ethanol blend fuel..

For my motorcycle and scooter I use a station with pumps with dedicated hoses for each grade. I think your concern is valid.

[ronigj]

Here in the Philippines I am using 95 or 97 octane gas on my 2009 KYMCO Super 8 and I have also try 100 octane w/o problem.

Sent from my Titanium S5 using Tapatalk

[klaviator]

I have owned a lot of bikes over the years.  Only two of them required more than regular gas.  Most people buying premium are just wasting money.  All of my current bikes run on regular.

The last bike I had that required higher octane was my Aprilia Sport City 250.  It called for 90 octane.  I would fill up with 93 octane and then often top off with a gallon or less of 87.  I tried to use pumps with separate hoses but in some parts of the country those are near impossible to find.

[Tiny]

I put 91 in my Movie. Tried 93/95 but it run like crap so I stick to 91 all my other scooters are two strokes so 87 for them.

[Tromper]

Well heck that's interesting, I've never had a vehicle not like the higher octane, but I could see it being an issue in theory.

Just for grins, what part of the world are you in Tiny?  Octane's measured differently in different parts of the world so I'd love to get an idea of what you're burning.

I put 91 in my Movie. Tried 93/95 but it run like crap so I stick to 91 all my other scooters are two strokes so 87 for them.

[Tiny]

I live in Mississauga Ontario Canada(city directly west of Toronto) and as odd as it may seem my Movie doesnt  like the higher grade fuels. With either 93/95 it sputters, hesitates, doesnt like to start and feels like it lost power. And its not me my wife has experienced it as well when she was on a day long ride for International Womens ride day and she put in 95 half way though the ride and she was having trouble with it til she refilled it the next day.

[de dee]

  I think my DT. 300i  has 11 to 1 compression, so I used 93 all the time,  now with my Piaggio 350i sport.   dealer said use regular gas, now I have 3,000 miles on it I am going to try 94   to see if there is any differance the piaggio has 12 to 1

[Tromper]

Wonder if your ignition timing isn't a tetch advanced Tiny, could possibly see a minor MPG, power & emissions gain by bumping it, but tough to say.
Personally I'd just smile and run the cheap stuff.

de dee, I really don't know but it's possible they detune these a bit (advance the timing most likely) for the N. American market, but it would be interesting to know if you see a bump in MPG.  In my experience you probably won't see much, if any gain.  I don't think the computer controls on these bikes are that complex but to take advantage of the higher octane it'd need to adjust the timing significantly, & even then since the compression ratio doesn't really change you won't see a lot.

There are a bunch of gas threads for 'bout every bike out there, including this one if you poke 'round a bit.  Mechanically it comes down to if ya ain't pinging you're fine.

[GLV55]

Here in the Boise area, we have quite a few pumps that only dispense 91 octane (whatever the US method is called, I think R+M/2) so we don't have to worry about mixing the other types in with it. Using this, instead of the ethanol infused stuff, I have never had any problem with my carb, including starting in the cold weather. About once every 4 months I will run a cap-full of Seafoam in the tank. So far, the scooter has run flawlessly.

[jeeves]

We only have 95 and 100 here.
There are 2 types of 95, normal 95 and class 95. The class has additives to keep the newer generation engines run better, or so they say.
I have put all of them in my tank, and can't say I felt any difference or noticable consumption improvements, so I fill the cheapest one.
The only occasion stumble or poor running has been when filling up on a  gas station that for some reason had bad quality gas at the time.

Correct me if I'm wrong, but high octane fuel is only needed in higher compression ratio engines 1:11,5 and higher because it prevents possible self detonation of fuel.


Sent from my Redmi 4 using Tapatalk

[CROSSBOLT]

Yes, Jeeves, you are 100% correct. The higher compression ratio, the higher the octane requirement. What is so puzzling is how Kymco gets an 11:1 engine to run on 87 R+M/2 gas without self destructing. Most of us old guys expect with that CR high octane would be required. I agree that the timing is probably the way they do it. The high CR is a smog requirement as is EFI.

Karl

[Tromper]

Kinda confused me too, so I did a hair of digging around to find out how it's handled.
The answer comes down to a variety of things that could be summed up as "computer controlled".
The nitty gritty involves timing combined with multiple pulse direct injection..

Then I did a hair of digging & found ad copy (Thanks Scooter Dynasty) stating:

"EFI System is the technique as the same level as the current automobile engine. It controls air inflow / fuel injection
ratio, fuel injection volume and injection timing through the computer programs and sends the mixed air and fuel most
appropriately into the engine through the nozzle spout, as well as to control the ignition angle to achieve the best
performance and pollution management. Also, because EFI system utilizes computer programs to control air inflow / fuel
injection ratio and fuel injection volume, it significantly enhances the horsepower and moreover to help improving
pollution and fuel-saving in comparison with conventional carburetor motorcycles."

In a nutshell, if it's as dynamic as a modern car's system..

A: I am impressed.
B: You may get a gain with a higher octane fuel.

Give it a shot if you have something special near ya.  91 might be enough for a difference, 94 almost certainly would be.

Please do post results along with the cost difference for the fuel and MPG gain.  I doubt it would pay for itself, but if you have more power you may go for it anyway.
At 60ish MPG I suspect you're not burning a lot of gas anyway so real dollars would be minimal.

Cheers

Tromper

Yes, Jeeves, you are 100% correct. The higher compression ratio, the higher the octane requirement. What is so puzzling is how Kymco gets an 11:1 engine to run on 87 R+M/2 gas without self destructing. Most of us old guys expect with that CR high octane would be required. I agree that the timing is probably the way they do it. The high CR is a smog requirement as is EFI.

Karl