Supreme gas for Yager?

[quinnmallory]

My scooter repairist said to start putting Supreme gas in it. Said it would make it last longer and was better for it. Can someone break down for me how the higher-priced gas is better for the Yager than the regular stuff?

[jprestonian]

No idea, and I am skeptical. Most scooter engines are not high-compression engines, which are what benefit from higher octane gasolines. The higher octane fuels actually "burn slower" in a lower-compression engine, so while they certainly won't harm your Yager's engine, chances are it's not going to help any, either.

One thang that confuses dealers, mechanics, etc., is the fact that the Asian scooters often come with documentation that indicates the recommended octane rating measured in RON, whereas in the U.S., we don't use that rating. We use (R + M) / 2 -- which is (RON + MON) divided by 2 -- or AKI (anti-knock index), as it is also known. Our ratings are slightly smaller numerically than equivalent RON ratings.

Wikipedia has a good article or seven on world octane ratings, and the whys and wherefores. Find out what Kymco recommends for the Yager in RON, and convert that to AKI, and use that fuel, and you'll be good to go.
.

[ScooterWolf]

Though I'm not a mechanic, my dealer suggested premium gas because the Yager is fuel injected engine. Not sure if that matters or not, but I've been following the suggestion. I spend no more than $7.00 US to fill my tank which will last a full week if I commute everyday (Monday -  Friday), but in the winter months I can go two weeks or more between fill ups.

-Wolf

[jprestonian]

Though I'm not a mechanic, my dealer suggested premium gas because the Yager is fuel injected engine. Not sure if that matters or not, but I've been following the suggestion.

Well, I've presented enough here that if you want to research it and possibly save yourself some money while not affecting either mileage or performance, you can do that, if you want. If you just want to believe what the dealer or the mechanic tells you, that's okay, as well.
.

[quinnmallory]

Thanks, jp...you've given enough info for me to do some research on it. Appreciated.

[Cortez]

Though I'm not a mechanic, my dealer suggested premium gas because the Yager is fuel injected engine.

You need a new dealer.
Premium gas is needed in high compression engines, 10.0:1 or more.

Maybe he just hinted at getting better quality fuel.
If you have fuel issues, it's because of junk or water in it, just change the
fuel station you use.

You DO NOT need premium gas and there's nothing that it will do for your Yager, unless
higher octane number gas (at that station) is also a higher quality gas (we sometimes
have that here).

[quinnmallory]

Thanks for the input. I think my only issue is that that the Kymco Yager user manual says to use an octane of 91, and the Supreme has here in Calif is 91 for the Supreme stuff (80-somthing for regular unleaded). But if it doesn't really matter, I'd opt for the cheap stuff over the boutique gas any day.

[jprestonian]

Thanks for the input. I think my only issue is that that the Kymco Yager user manual says to use an octane of 91, and the Supreme has here in Calif is 91 for the Supreme stuff (80-somthing for regular unleaded).

[tears hair out]

I rode 91 yesterday.

91 what?  Miles?  Yards?  Feet?  Kilometers?  Inches?  Minutes, perhaps?  

See, the number means very little unless you know in what units something is being measured.  If I told you it was 28 degrees outside without telling you which scale I'm using, it could be very hot, or quite cold, right?

From earlier this thread:

One thang that confuses dealers, mechanics, etc., is the fact that the Asian scooters often come with documentation that indicates the recommended octane rating measured in RON, whereas in the U.S., we don't use that rating. We use (R + M) / 2 -- which is (RON + MON) divided by 2 -- or AKI (anti-knock index), as it is also known. Our ratings are slightly smaller numerically than equivalent RON ratings.

Put another way, the world uses three different "octane yardsticks" for measuring octane in gasoline (commonly -- there are probably others as well, but these are the ones you can expect to find at gas pumps); Taiwan uses RON, whereas the U.S. uses AKI. The AKI yardstick's marks are slightly farther apart than the RON yardstick's marks, meaning that measuring the same thing, the AKI number is slightly lower than the RON number.
.

[Cortez]

Yep.

Premium gas here is 98 and 100 octane (EU), and 95 is the regular stuff.

[jprestonian]

Yep.

Premium gas here is 98 and 100 octane (EU), and 95 is the regular stuff.

Guessing that your country's measurement standard is RON, rather than MON or AKI.
.

[quinnmallory]

[tears hair out]

I rode 91 yesterday.

91 what?  Miles?  Yards?  Feet?  Kilometers?  Inches?  Minutes, perhaps?  

 ...

Yeah, I got all that...I was just confused by the Yager manual...but as I said, I'd rather go with the cheaper, non-91 octane fuel anyway, so no biggie.

As for me, I'd never ride the 91. It's one of the most hated freeways in SoCal. Edge traps everywhere.

[jprestonian]

Yeah, I got all that...I was just confused by the Yager manual...but as I said, I'd rather go with the cheaper, non-91 octane fuel anyway, so no biggie.

As for me, I'd never ride the 91. It's one of the most hated freeways in SoCal. Edge traps everywhere.

But now you know to look for those magic letters: R O N

Those were appended to the octane number recommended in my Kymco manual. I'm hoping they're there in yours, too.
.

[zombie]

Basically octane rating is the fuels flash point. Higher octane requires a stronger ign. source. Most scoots have very unfinished parts inside the engine, and therefore tend to attract or hold alot of carbon. This carbon can act as a glow plug pre-igniting the fuel mix causing detonation or ping. Higher octane fuel resists pre ignition. Higher octane has a few other side benefits. Increased mileage, and less carbon residue. I have proven this out to MANY friends. You will SAVE money by spending more per gallon as your mileage will increase. Try it on three tankfulls to prove it yourself. Also most new engine controls have knock sensors to retard timing when pre-ignition is present. That is how they can recommend lower octane fuel. The obvious draw back is performance/ mileage suffer.

[jprestonian]

Basically octane rating is the fuels flash point. Higher octane requires a stronger ign. source.

... or higher compression, which is what octane is really about. Pre-detonation is a destructive force, and would be especially so in a single-cylinder engine that had a high compression ratio, trying to burn fuel with too low an octane rating. However, that isn't the case with our Taiwanese beauties.

Again, 91 RON = 87 AKI. There's just no getting around that fact.
.

[Cortez]

I just figured out that my DT300 has 10,8:1 compression.. I should probably use premium gas.. and
I figured I'm home free when I got rid of my Kawasaki with 11.3:1..