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Aviation Fuel?

11 posts in this topic

I have not ran av-gas for a long time, I'm talking late 70's. Back then you could not buy race fuel at the pump and if you could it was hard to find and expensive. So av-gas came into the picture. It is a minimum of 110 octane and may still contain lead. It makes a motor come alive for sure.

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ran it in the 2-stroke before getting head milled. I think you would be wasting your $$$ for no gains.

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in a complete stock motor you will be better off running 50/50 mix. A bike with pipe,jets and 12.5.1 up (you can't run it in a bike under 12.5.1 comp the head will not hold up) comp and so on run straight 110 plus for a big improvement.. I use to run this fuel in my drag raptor. it smells good too

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There is no advantage in running AvGas unless the pump automotive fuel in your area is of an exceptionally low quality (like 10% ethanol). In that case, it might run better. But, AvGas is blended for engines that have long intake tracts, run at a steady low rpm, and operate at very low temps at high altitudes. It is, therefore, completely wrong for an engine that is the exact opposite of all of that, as is your motorcycle.

In either case, there is also nothing whatsoever to be gained from running any more than 95 Research octane (which is roughly 87 Motor octane, or a US pump anti-knock index of 91) unless your engine exhibits a tendency to detonate (ping) on fuel at that octane level.

Race fuels can provide more power by virtue of a higher energy content (NOT from higher octane), but only if correctly jetted.

Save your money.

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Does anyone run aviation fuel in their STOCK yz450f? Any noticeable advantages/disadvantages?

Everyone thinks there is an "advantage " to running AV gas as a performance booster. Totally FALSE.

Here's some facts to remember to put the myth to bed:

100LL (low lead content) is not 100 octane as we rate it for pump gas (R+M/2). It is actually 96 octane by that measure.

Lower Specific gravity than pump (density) means you actually run leaner with the same jetting.

-Important one here!!! Lower flame speed than race gas. 100LL is designed for a sustained 3500RPM operation. If you run consistently higher than that you will be spitting unburnt fuel out the pipe.

If you have bumped compression or modified ign timing, you probably need race fuel such as VP C12 or CAM II , if your engine is stock, don't waste your money on race fuels, spend the money saved on a fresh OIL CHANGE.

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im not sure about av gas. But i ride a wr250 (all free mods and cam) and live in ontario. The regular pump gas is rated 91 octane, and some places such as sunoco have a fuel that is rated at 94. I usually run the 94 but there are times where i couldnt get it for what ever reason and i find that the bike just over all runs smoother on the better fuel. Not necesarily more power, just smoother.

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It depends on how the fuel is rated in Ontario. There are three principal ways of rating octane number. Research Octane, which is what the manual mentions when it calls for 95 octane minimum, Motor Octane, which is more realistically representative of what really goes on in an engine but which shows a lower number for a given level of detonation resistance, and the Anti-Knock Index, used in the US, that averages the two. This is posted as (R+M/2) on the pump. A Research Octane of 95 is roughly the same as an AKI of 90, and a Motor Octane of 86/87.

If you are using a 91 Research octane fuel, it's not adequate. If it's an anti-knock index of 91, then your rougher running is a fuel quality issue, unrelated to the octane number of the fuel.

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What gas stations or i should say what brand of gas does not contain ethanol?

I have heard not to use fuel that contains ethanol cause it ruins the motor or makes it run bad and can damage the carb on 2 strokes but i dont know on 4 stroke with fuel injection.

I believe exxon gas doesnt contain ethanol but i dont know on the others.

I know Marathon,phillips,shell and Kangaroo stations contain ethanol and BP.

Be nice if we had a list of gas stations that didnt contain ethanol so we wouldnt be looking or stoping at every gas station.

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It depends on how the fuel is rated in Ontario. There are three principal ways of rating octane number. Research Octane, which is what the manual mentions when it calls for 95 octane minimum, Motor Octane, which is more realistically representative of what really goes on in an engine but which shows a lower number for a given level of detonation resistance, and the Anti-Knock Index, used in the US, that averages the two. This is posted as (R+M/2) on the pump. A Research Octane of 95 is roughly the same as an AKI of 90, and a Motor Octane of 86/87.

If you are using a 91 Research octane fuel, it's not adequate. If it's an anti-knock index of 91, then your rougher running is a fuel quality issue, unrelated to the octane number of the fuel.

Ontario, (all Canada) is the same octane rating system as the US, R+M/2

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Ontario, (all Canada) is the same octane rating system as the US, R+M/2
I thought that was the case, but I wasn't sure.

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