I just bought a 2000 Yamaha WR400f for a trail bike two weeks ago and I just read in the service manual that the 89-02 YZ-WR 400-426 should run 95 octane or higher. Premium pump gas in Minnesota is 91, 92, or 93 mainly 91. It'll be a pain to have to run race gas or something for a trail bike.

The highest pump gas and that octane boost? I heard that octane boost additive is junk.

(pump gas not being 95)

 

jus run 93 it will be ok

 

93 will be perfectly fine. Until you port it or hear it ping it will be fine. If it pings try some booster (I guess Klotz is one of few goods ones out there) or if you port it I would ask the person who did it if you need race gas.

 

get some cam II or Unical and go like hell....actually i have heard that the "octane" rating is a hype, that 89 octane fuel will do just fine. An independant lab tested a ZX9R (i believe) on a dyno, they ran 87, 89, 91,93. The HP diffrences were so small that they would be undetectable to a human. They said that the smallest variances were with 89 and 93 in which there was a small fraction of a HP between the 2 fuels. I run 89 in my CR250R , EX300, and Boat (Merc 85hp) and i have never had problems i did run only 93 in the 900rr though. Just out of habit. The only reason i can think that a manufacturer would want high test is because of the deposits that the refining process didnt remove for 87 fuel? Maybe someone here actually knows the facts i would be curious to know.

 

Running higher gas than needed can result in worse performance (like you said unnoticable though) and a waste of money (5$ for a gallon of race gas). I just stick with 93 for good measure.

 

We use 93 in our bikes for trails and just ridin for race we use VP. personally i dont think it does that much but i like the way it smells lol

 

yep i run 93 also, it aint failed me yet

 

That really just a waste of money. If you can run 93 just run 93. If it detonates or you port/bore the bike and they guy that did it says to run race gas then you should. Otherwise all stock bikes (with the exception of the 2005 yz125) will run perfectly fine on 93.

 

yeah i know like i said its pointless. I think im guna bore my bike anyways. But we do use 93 a lot

 

Okay that's kind of what I figured, but what if I can only get 91 or 92? I guess I'll have to go high octane hunting to find which gas stations carry 93.
Thanks, I haven't even road it more than on my street. I've ahd it 2 weekends and both weekends, I've taken it apart. yeah for tune up's hahahahaha

 

Not much difference between 92 and 93

 

I found 93 by my house (minnesota), but my parents cabin is in wisconsin so I'll have to find some up there.

 

Im in Wisconsin and everyplace around here has 93. Even one station has 104.