Premium Gas vs cheap stuff

9 replies to this topic
  • Teamblue450

Posted April 12, 2008 - 06:17 PM


I just bought my 08 YZ450F, and the guys at the shop told me to use cheap gas as opposed to the premium my owners manual recommends. We live at 6500 feet in the CO mountains, and they said something about the higher octane gas runs to rich. Do they know what their talking about? First ride tomorrow.

  • BASSic

Posted April 12, 2008 - 06:33 PM


Higher octane fuel won't affect how rich or lean your engine runs. With lower octane fuel, you may experience engine knock also known as detonation where the fuel ignites sooner than it should, which isn't good for your engine.

Considering the relatively small price difference between low and high octane fuel, I think it's best to go with the higher octane fuel, especially in a performance engine such as that of the YZ.

  • MaxPower

Posted April 12, 2008 - 06:37 PM


[COLOR="Green"]I didnt feel like going to the station and filled my empty tank with mower gas. I was shocked that the bike ran fine, no pinging, good response, fine.
Now I run regular.

I remember hearing something about lower octane fuel buring better at elevation.I dont think he was hornswaggleing you.

How is a 450 in the thin air?
Is there a noticeable difference?

  • MaxPower

Posted April 12, 2008 - 06:43 PM


  • almostinvincible119

Posted April 12, 2008 - 08:02 PM


if you ride old man speed. go for it

but its an extra 20 cents a gallon guys....gimme a break

dont skimp

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  • MaxPower

Posted April 13, 2008 - 05:26 AM


[COLOR="Green"]or skimp by using wiesco pistons. You have a race bike, use race parts[/COLOR]

  • USED YZ426F

Posted April 13, 2008 - 05:49 AM


Provided everything else is working properly and dialed in right (jetting, no mechanical issues), you can normally lower the needed octane rating by 1 point for every 1000 ft of elevation above sea level.

So, if you are running at 6500 ft, and the owners manual recommends 93 octane, you should be able to get by with a decent 87 octane fuel.

If, however, you experience knocking, pinging, detonation, whatever you want to call it, you should use a higher octane fuel.

  • Teamblue450

Posted April 13, 2008 - 06:29 AM


Thanks for all the info. I've ran an 02 426 for 4 years, and always used premium, so i thought it was weird that they recommended lower octane fuel with my new bike. I'm sticking with the recomended premium. when your talking about an additainal $.50 is it even a question...

  • fundgh

Posted April 14, 2008 - 07:49 AM


I know this topic has likely been beat to death all over the internet. But the logic of saying that it only costs 20 cents more so don't skimp, is just as wrong as saying premium gas is better quality. If your engine doesn't require it (ie no predetonation with lower octane), then it is pointless to use it and in extreme cases can be worse for you. It should be safe to go with the manufacturers suggestion, but if you do your own testing and find that it runs fine on 89 or 87, then there is no need to go higher. I used 91 for my first fill up on a long ride Saturday and ran it from 3k ft up to 6-7k ft and it ran fine. UP at 5500 ft, I put 87 in it and rode back down to <1k ft and it ran fine as well (YZ400f). So I think I will try a full tank of 87 at low elevation next, and if it continues to run fine, I will stick with that and save my $.20 per gallon.

  • almostinvincible119

Posted April 14, 2008 - 09:29 AM


[COLOR="Green"]or skimp by using wiesco pistons. You have a race bike, use race parts[/COLOR]

dude, im lost
i love my wiesco. its better than the stocker. i think youve lost it. maybe you just dont get the quality over in the vatican city like we do here in the U.S.

they must have something agianst you euros

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