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Aviation Fuel Use

Towmanjim

New member
Just curious if anyone has had any experience using 100 Low Lead aviation fuel in their bike. Mine, 05 1200GS seems to run better with octanes above 90. It is also nearly impossible to get 100% gasoline in the Phoenix area.
 
Interesting question, I was going to ask if anyone was aware of the properties of current small plane fuel. The VP racing fuel I just bought was, no ethanol, from the pump was 108 octane and $10.00 per gallon. I was interested in the no ethanol aspect.
For your bike, I think you need completely unleaded so as you don't clog the catalytic converter.
OM
 
<<< Disclaimer >>> Use of aviation fuel for road use is really not legal.

That said, why would you use any leaded fuel for a bike designed to run without it?

I recently read in an aviation magazine that the FAA is starting testing of alternative no-lead fuels for civilian aviation. The goal is to eliminate low lead avgas by about 2018.
 
Apart from the fact that Avgas use is illegal in anything but an aircraft, and that it will be completely phased out by 2018, you might want to consider some of its annoying quirks:

- 100LL will foul plugs rapidly, and probably even more in newer machines since those are designed to run very lean (Lean of Peak) and cool. Unless a critical temperature is reached and maintained in the combustion chamber, plugs and everything else tends to get caked with lead deposits as the scavenging agent cannot work effectively. Part of the 50 hour inspection ritual on aircraft is to sandblast the plugs, and scrub off larger lead deposits on the plug porcelain, otherwise the electrodes get shorted out.

- Valves and valve guides are designed at the factory to run with or without leaded fuels. A problem can arise when valve guides get clogged with carbon and lead deposits. Most piston aircraft engines need a 500 hour inspection and valve guides reamed to eliminate these deposits. Valves get stuck and pistons hit them and break off the valve from the stem when this isn't done.

- If your bike is equipped with a catalytic converter, it will get blocked very quickly and need to be replaced soon.

- If you use synthetic engine oils, you will get lead deposits in the engine crankcase and clogging the journals, eventually leading to engine failure from oil starvation. If you use leaded fuels regularly, you *must* use at least semi-synthetic oils, or preferably dino oils.

IMO, unless you have an older very high compression engine, you probably won't get any benefits from using 100LL.

francois
 
With octane, more is not better.

You only need as much as your engine requires. Any more than that is just wasted.

It's also hilarious that so many think ethanol degrades gasoline. It does, but not as far as octane is concerned, as ethanol is an octane enhancer.

Octane is nothing but a measure of a fuel's ability to resist knocking.

The fact a higher compression engine tends to knock more on a particular fuel than a lower compression engine combined with the fact the higher octane fuel prevents it does not mean it was the fuel that created the extra power---that was the higher compression. Same thing with ignition advance. You can't pour in more power unless you're talking nitro.
 
Another factoid: The LL (Low Lead) in 100LL is low only in comparison to other aviation fuels. It contains about 4 times the lead that was found in automotive gas back in the day. Using leaded gas will poison your catalytic converter in addition to to the other mentioned maladies.

My '05 ran just fine on mid grade California fuel. The bike was spec'd for an AKI of 89. I'd look as to why your bike doesn't run well using the specified fuel. Ethanol may effect your MPG but as noted by others it is an octane booster. It is possible that in your quest to get 100% gas you are getting poor quality fuel. It happens. Forget about the ethanol content for a few tanks and fill up with name brand gas from a busy station.
 
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With octane, more is not better.

You only need as much as your engine requires. Any more than that is just wasted.

It's also hilarious that so many think ethanol degrades gasoline. It does, but not as far as octane is concerned, as ethanol is an octane enhancer.

Octane is nothing but a measure of a fuel's ability to resist knocking.

The fact a higher compression engine tends to knock more on a particular fuel than a lower compression engine combined with the fact the higher octane fuel prevents it does not mean it was the fuel that created the extra power---that was the higher compression. Same thing with ignition advance. You can't pour in more power unless you're talking nitro.

This always makes me remember the fuel portion of the owner's manual for my 2000 Ford Mustang. I'm paraphrasing but it came right out and said that the engine was DESIGNED to run on regular gas with a rating of 87 octane (or whatever regular normally is) and that was what should be used. It warned that use of fuels with higher than 89 octane (mid grade) could cause damage and would not improve performance or fuel economy. While I don't think it would cause damage Ford came right out and said regular gas in everything except the SVT Cobra which wasn't available that year.
 
Apart from the fact that Avgas use is illegal in anything but an aircraft, and that it will be completely phased out by 2018, you might want to consider some of its annoying quirks:

- 100LL will foul plugs rapidly, and probably even more in newer machines since those are designed to run very lean (Lean of Peak) and cool. Unless a critical temperature is reached and maintained in the combustion chamber, plugs and everything else tends to get caked with lead deposits as the scavenging agent cannot work effectively. Part of the 50 hour inspection ritual on aircraft is to sandblast the plugs, and scrub off larger lead deposits on the plug porcelain, otherwise the electrodes get shorted out.

- Valves and valve guides are designed at the factory to run with or without leaded fuels. A problem can arise when valve guides get clogged with carbon and lead deposits. Most piston aircraft engines need a 500 hour inspection and valve guides reamed to eliminate these deposits. Valves get stuck and pistons hit them and break off the valve from the stem when this isn't done.

- If your bike is equipped with a catalytic converter, it will get blocked very quickly and need to be replaced soon.

- If you use synthetic engine oils, you will get lead deposits in the engine crankcase and clogging the journals, eventually leading to engine failure from oil starvation. If you use leaded fuels regularly, you *must* use at least semi-synthetic oils, or preferably dino oils.

IMO, unless you have an older very high compression engine, you probably won't get any benefits from using 100LL.

francois

And if you've ever had to burn off lead deposits at runup in a Cessna then you understand why you don't want to use it in your car or motorcycle.
 
And higher octane fuel ignites slower, the higher the octane.

If it is compressed more (read: high compression engine) it works fine. Usually you would want at least 12/1 compression to run 100 octane.

By using high octane fuel in a low compression engine your available power will in fact suffer.

Ken
 
And if you've ever had to burn off lead deposits at runup in a Cessna then you understand why you don't want to use it in your car or motorcycle.

Been there, done that. And I still have not found the mixture knob on my roadster!

I does rather look like a 2 cylinder Aeronca-JAP J-99 though.

300px-JAPJ99.JPG

Years ago I drove a fuel truck at Santa Monica Airport, and the mechanics told me av-gas in my bike was a bad thing.

Scott
 
Non Ethanol is much better

Here in Florida we can get Non Ethanol gas a the newer Racetrack gas stations. You can tell the difference in mileage, performance and temp, in my humble opinion it is well worth the extra $$$ to use it over the regular crap.
 
With octane, more is not better.

You only need as much as your engine requires. Any more than that is just wasted.

It's also hilarious that so many think ethanol degrades gasoline. It does, but not as far as octane is concerned, as ethanol is an octane enhancer.

Octane is nothing but a measure of a fuel's ability to resist knocking.

The fact a higher compression engine tends to knock more on a particular fuel than a lower compression engine combined with the fact the higher octane fuel prevents it does not mean it was the fuel that created the extra power---that was the higher compression. Same thing with ignition advance. You can't pour in more power unless you're talking nitro.

What he said, running :better" on high octane, is in your head, unless you are racing a modified machine.
 
Just curious if anyone has had any experience using 100 Low Lead aviation fuel in their bike. Mine, 05 1200GS seems to run better with octanes above 90. It is also nearly impossible to get 100% gasoline in the Phoenix area.

100LL has the ability to kill both O2 sensors and poison the catalytic converter, all in a few hundred miles.
 
And higher octane fuel ignites slower, the higher the octane.

If it is compressed more (read: high compression engine) it works fine. Usually you would want at least 12/1 compression to run 100 octane.

By using high octane fuel in a low compression engine your available power will in fact suffer.

Ken

My RT has 12:1 and the new water cooled one is 12.5:1 I think.
 
With octane, more is not better.

You only need as much as your engine requires. Any more than that is just wasted.

It's also hilarious that so many think ethanol degrades gasoline. It does, but not as far as octane is concerned, as ethanol is an octane enhancer.

Octane is nothing but a measure of a fuel's ability to resist knocking.

The fact a higher compression engine tends to knock more on a particular fuel than a lower compression engine combined with the fact the higher octane fuel prevents it does not mean it was the fuel that created the extra power---that was the higher compression. Same thing with ignition advance. You can't pour in more power unless you're talking nitro.

The 1200 RTs have 12-12.5:1 compression ratios, depending the year/generation. Engine management keeps them running fine on pump gas, but my vintage will run better on 93-94 octane than 87 or 89. The ignition will be retarded if ping is detected. This will cut back on power output and yes I can tell the difference. My 2009 Suburban is flex fuel. If I use E85, it will make additional torque and HP as specified in the Manual and again, it's noticeable enough. Now, will 100 octane make a difference in the RT? Probably not, but the crap fuel we have here in Phoenix, I will get ping with 91 if it's warm enough outside. Never had that in Iowa, so I assume it's gas quality or lack of it here. I'd love to put a gallon of something higher octane to bring it up and see if it still gets ping.
 
Performance number is not equilivent to octane number.

Aviation gasoline is run on completely different engines than mogas. If you could run avgas on mogas engines I don't know what the result would be, (I didn't want to get fired) but I do know that to blend up octane in mogas I sometimes did use aviation alky WITH NO LEAD ADDED to fix a low octane mogas batch. I would guess that leaded avgas mixture in an engine would be exiting through the exhaust valves still burning. Valves wouldn't last very long.
 
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Loved all the inuiput, thanks to all. Probably will not run any avgas, but I am convinced that non-ethanol gas is much better. When I am forced to run the ethanol it pings under acceleration. Pretty sure that is poor gas. Guess I have to try to rely on PureGas to get me to stations that have non-ethanol. Always fuel up before I get back to the PHX area.
 
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