Fuel Curious......

3 replies to this topic
  • Yzf_Buz

Posted July 30, 2011 - 11:35 PM


I have been reading a lot of posts and I am curious as to which fuel really should be run through my bike. I usually run pump 92 in it. Does the ethanol that is being put in the gas now days have any ill effect on the guides or seats at all? Also does the better fuel help preserve the integrity ob the bottom end of my motor ? I am rebuilding my bike (an 06 450) and am looking at changing what fuel I run in it. Thanks for the input......

  • grayracer513

Posted July 31, 2011 - 07:08 AM


Ethanol affects the non-metallic parts of the fuel system more than anything else, and some plastics can be damaged by it. Don't see much of that, though.

As far as valves and guides, and the rings, it depends on the amount of ethanol in the fuel. The guides and compression rings are lubed by the fuel, not engine oil. More alcohol makes the fuel "drier", and can reduce the lubricity of the fuel. At 10% or less, thie isn't a major factor, IMO. Then too, alcohol isn't the only thing that will do that, and some race fuels are a little like that with no ethanol whatsoever.

It has no effect on the valve faces and seats.

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  • Yzf_Buz

Posted July 31, 2011 - 12:41 PM


Thanks for the reply. Can you tell me if a higher octane fuel helps preserve the integrity of crank bearings or other parts or is this a myth my friend was telling me ? I am considering this but am trying to get an idea if I can even purchase the fuel in my area. Thanks again :smirk:

  • grayracer513

Posted July 31, 2011 - 01:26 PM


Of course not. Octane has nothing to do with any such thing. Octane number rates the fuels resistance to being ignited by heat, pressure, or any other source of ignition other than a spark or an open flame. In other words, the detonation, or knock (ping) resistance of the fuel, and not one other thing.

Now, if you were using a fuel that had a low enough octane value that is caused knocking under a load, then yes, using a fuel with an adequate octane number to eliminate pinging will actually help the engine live longer, but once you have enough octane to achieve that, you don't need any more. Using a higher octane fuel than necessary won't cause any harm or problems, but it won't help anything, either.

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