What octane fuel do you use?

Ok, Just got my WR426 today and in 40min the throttle stop was cut and the baffle, along with the air box top, were removed and she was ready to go....then I had to go to work. So as the subject reads I know I'm suppose to run 95 octane but the 2 I can get are normal 93 octane and 112 octane. What fuel do you guys run? If you have had any problems PLEASE tell me which fuel(s) NOT to use and why. Thanks


I run 93 cause thats the highest I have in my area, if your worreid about not having 95 then check this out http://www.ibmwr.org/otech/octane.html explains Octane ratings real well

Ok, I just read the "octane war" on the YZ426 page. I am not wanting to start any fights or wars. I would just like to know what fuel you use, why, and the problems you may have had with other fuels you tried.


I havent tried lower than 92, but its running just fine. The guys at My local Yamaha said that Not all Gas is the Same even based on a 92 octane rating, and where I get my gas can vary the way the bike runs from station to station. I get mine from Shell, and Texaco..but primarily Shell. The manual recommends 95, because you "could" need to use a Octane booster to get the fuel up to 92 octane (as in my case and might not be as good as the pump says) and that will ensure a good fuel.

If the bike isnt pinging.. (sounds like Marbles in a can and is very noticable.(this also could also be referred to as a type of metallic Slapping sound) when the bike runs then its fine.

Because pinging is a detonation caused by a "too rapid" burn of gasoline in the 12.5 to 1 Compression combustion chamber the Monster Wr and YZ makes the "Detonation" will wipe out pistons, Valves and cause poor running. Try your 93 in your area. I think it will do just peachy. If not, Add a booster. :)

All of What ive read about anything over 100 Octane in the Wr and Yz is that it doesnt like it much.

Remember.. Adding octane "dilutes" the Explosion resulting in less "BTU'S" (british thermal units) and consequentially..less heat. Therefore less power. But at 12.5 to 1, you dont loose anything because the Explosion still is very violent due to the Greater Compression of the Fuel and Air.

So..87 Octane is Much more Explosive than say 93.. but..also can cause severe damage if used in such a High compression engine.

Anyway, Sorry for the Lab Lesson, but I thought Id put in my opinion.


Good luck.

I'm trying Amaco 93 octane. If I have any problems I'll post them. I'm also just breaking in my bike and I won't be riding it hard till this Sun. on it's 1st big ride.


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