Av Gas? Anyone run it?

This may be a stupid question but I have heard of guys/gals running Aviation gas in their bikes (2 and 4T). Considering how crappy the fuel with the ethanol is here on the East Coast, and how expensive race fuel is I'd like to learn more.

Good luck with this. Many times this is like asking what kind of oil to run I have ran it for about 15 years in all sorts of different engines. Boats, inboard and outboard, bikes, two stroke and four stroke, and even my 4x4 that I leave at the river to launch my boat. It has never caused me any problems, I believe it has prevented some because it is high, consistent quality and doesn't spoil for a long time. Just my opinion, no warranty expressed or implied.

I run 100 octane av gas in my WR300 with Klotz synthetic pre-mix. Bike runs great on it. I used to run standard pump hi test and I noticed in the cold weather I'd have weird globs in my fuel can screen below the pour-spout. I get it from a local air strip. Cant put it in the bike directly from what I gather. I pump it into my fuel can. I think it was around $5 a gallon but Im guessing.

Especially useful with 2 stroke mixes because the oil displaces the octane.

I run 100 LL Avgas in my 165. I had detonation issues with pump premium. I pay about $6-$6.50/gallon at the local air strip. Works great. I really like how stable it is. I don't really have to worry about draining the carb if the bike is going to sit for a few months.

Our pump gas up here in AK is ethanol free, but the highest octane you can get is 90. I've heard of some people adding a little 100LL avgas to give it a bump. Despite the "low lead" label, 100LL avgas has about twice the lead as standard 80 octane avgas, and about 4 times as much as leaded regular used to have. Running it straight can create a lot of lead deposits on valves.

Jeeez - I run 87 in my airplane under FAA STC. 100LL is frackin $6 a gallon - no thanks!

I got crazy with head work on a bike years back and wound up using 100LL. It just got to be a pain. I have a buddy rider and also a pilot that swears that his valve life is exponentially increased by running 100LL. He is uber-rich so he doesnt care. I, on the other hand, live int he real world and have mouths to feed. I run 87 in all my bikes because power is usually not the thing that keeps me from finishing 1,2 or 3. It falls squarely in the skill category. I have yet to finish an enduro and wish I had more power...

Avgas is not really a good choice for terrestrial machines. It's formulated for high altitude and cold temperatures. Read-up on Reid Vapor Pressure (RVP). Anybody that has flown light aircraft can attest to the different feel of Avgas on their skin. A pre-flight inspection includes a check for water in the fuel tanks. Eventually you spill 100LL on your hands, and it evaporates very quickly at low altitudes. It feels more like alcohol than gasoline. It's very different from the 91/93 available at the corner station. The short story here is that avgas is intended to work at cold temperatures and low atmospheric pressures in engines that are more like your lawn-mower Briggs & Stratton than your Husky's race motor.

Race gas is a far better choice for motorcycles, and is available almost everywhere. Sunoco and Torco both make great race fuels. Both companies have fuel finders on their web pages. I have a 100 octane pump 15 miles from home in Sunol CA. They also sell 5 gallon cans of 104 through 118 octane that can be mixed down to whatever you need. I bet there's a dealer near most of us. Buy a 55Gal drum and a quality hand pump and you can mix and dispense a custom blend that is exactly what you want/need.

We use Torco race fuel. Fyi - 91 octane is minimum in the 449/511's if you want them to last. Especially if you run our pcv maps.

I like the basic 108 octane race fuel. The exotic mixes tend to eat fuel injection components on motorcycles, so fyi if you loose your fuel pump 3 months down the road after running the power mixes, you know why. Two strokes, skys the limit. I always wanted to make a 2 stroke diesel, but never had the time, maybe some day.

Up here in AK where the highest octane pump gas available is 90 AKI, a half gallon 100LL avgas mixed with 4.5 gallons 90 AKI octane ethanol free pump gas makes 92+ AKI fuel which is slightly higher than the 96 RON required for most european dirt bikes. Mixed at that ratio, the vapor pressure of the avgas is of no concern.

I feel like I'm in a different time warp or something from most ... I have ~never had much if any gas pump, gasoline issues except from letting a bike sit for a couple weeks ... I've even owned a bike that the previous owner said would only run on some sort of vp race gas ... Found out that was BS also ...

Don't know what this 3rd world gas is, but no real problems here unless my bike sits or I just run too much gas from the bottle fill up stations here ...

Good luck on your gasoline choice ..

I'm with you on that Ray, I just go to any petrol station and fill up, our standard octane is 95 and super is 97, I can't notice a difference between them so stick with the lesser as it's cheaper, still pay £1.30 per litre though.

Usually, I run the higher octane here most times because the price is so close to the lower octane stuff (and I wanna be with the cool kids) but when I do run the lower octane, no pinging or knocking from my bikes...

I'm not 100% sure whether octane is naturally occurring in gasoline when the crude oil is being cooked or not, but octane simply helps controls the detonation of gasoline. It is not a power rating. If your engine is not knocking \ pinging at 90 octane, I'm not sure you get any real benefit from paying for higher price stuff. Again, just a plain dirt bike rider here. Not a PRO on any level except drinking and BSing,.. maybe :0)

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I did just go read some on gasoline ... The web is so cool at times... Most of us have zero reason to be ignorant on many subjects now ... And I found the last paragraph below out there. I've run that 100 RON Blaze here ... I still finished near last place in my races ... I do sort of like that no ethanol blend idea, but if I'm not mistaken, the price of Blaze was much higher(I'll verify this later) ...And it has to be hunted down around here ... I do very little hunting in the cities now.

So, in my case...Do I pay more for gas and be able to park my bikes for weeks and not have my CARB get all gummy due to ethanol? Or do I simply save money on my gas bills here and ride more, fighting off my gummy CARB issue that way? Check the ride reports and you will see the path I chose ...


Apparently all countries have slightly different blends of gas ... Here is the gas-word on the 3rd world country I'm at presently:

Philippines: A brand of Petron, Petron Blaze is rated at 100 RON (the only brand of gasoline in the Philippines without an ethanol blend). Other "super premium" brands like Petron XCS, Caltex Gold, Shell V-Power are rated at 95-97 RON, while Petron Xtra Unleaded, Caltex Silver, and Shell Super Unleaded are rated at 93 RON.

I'm starting to feel like a gasoline thread, is really an oil thread in disguise ...

Take this AVgas ... It is not formulated to be run on the ground apparently ... Yet we do it... We run diesel oil in non-diesel engines, auto oil in bikes ... ETC ... Crude oil is a tricky customer and wears many different hats ...

The primary difference between avgas and mogas is that mogas octane is boosted by added aromatics such as toluene and benzene, while octane in avgas is boosted by adding long-chain alkanes and alkenes which are more expensive but do not have the negative issues such as corrosive ethanol or high vapor pressure associated with mogas (vapor lock in in your Lycoming at 10,000 feet is not a good thing). There is no negative outcome with running 100LL in your bike other than the buttload of lead it contains which can foul plugs and create lead deposits in the head and valves which can eventually cause detonation. Avgas is very high quality fuel, and combustion temperatures are the same at 10,000 feet as they are at sea level, and 100LL is intended to be run in high-performance, fuel injected turbocharged and supercharged aviation engines, which are in no way as simple as lawnmower engines as has been suggested above.

And the idea that it is designed to only run at high altitude is false. How does the plan get up there? It has to take off at ground level at a point where the motor needs PEAK power to take off.
And I can't believe no one has mentioned, IT SMELLS GREAT!!!

The above is totally true. I am adding to this post because I am a licensed FAA Aviation maintenance technician rated in both airframe and powerplants.

Although many piston driven airplanes have a low static compression, detonation is a No No in aviation. Many of these piston engines run a supercharging system whether gear driven or Turbo supercharging systems which are exhaust gas driven and these systems simulate sea level conditions for maximum power at take off. The amount of actual boost ( if any) is controlled by an altitude sensing bellows which keeps the boost at these sea level conditions, ( 29.92 inches of Mercury, or about 15lbs of pressure). Unlike automotive turbo charging systems that actually see Boost beyond the naturally aspirated pressure of 15lbs. Airplanes seldom do see actual boost beyond that or ever go beyond "Death Valley, below Sea Level, Mineshaft conditions" . Which is more than 30.00 inches of mercury and would be approaching 16 or so lbs per square inch pressures on the intake charge. The supercharged aircraft piston engine has this system installed so it can get to maximum power at take off period. It can make its 15lbs of pressure even at altitude as well so it can carry it's rated load and take off. Your average naturally aspirated engine in a "putt putt" airplane can't make there rated Horsepower unless they are at sea level. Thats where your Turbocharging comes into play here. It continues to make the rated horsepower at Altitude as well, as horsepower is diminished as altitude goes up. So the loss of horsepower is overcome with the turbocharger or supercharger. Allowing them to fly at higher altitudes.

How many times have you heard the old stories of bush pilots taking people up into the mountains to some lake to go fishing and land on the water and drop off all their gear and supplies. Then a week later try to carry them out with all their gear and fish as well and can't gain enough altitude upon take off to clear the trees. They end up crashing into those trees, Altitude is the culprit. Add to that the fact many of these lighter aircraft are not supercharged to allow maximum power at take off.

The higher Octane levels in Aviation fuels are there to keep the engine from detonating. Not that it actually needs it but that its for safety reasons to avoid detonation. I believe Avgas has a slower burn rate than automotive fuels and racing gasoline. Which means flame probagation is slower in the combustion chamber in aviation applications. As most of these engines do not see the RPMs of the modern day motorcycle or car engine for that matter. They are built to have huge connecting rods, large wrist pins and heavy pistons to take the possible abuse of detonation so they don't fall apart and fall out of the sky.

It does smell good, but it will also burn your eyelids when run on the street as I used to mix it with pump gas in my 426 Hemi car. To much blended though with the pump gas would cause the car to load up and it had to be blown out, out on the highway, which is what the idea was anyway. While blowing off a few "Chevies" and putting some money in my pocket.

My opinion, if you need higher octane gas, because you have a detonation problem then run race fuel in your higher RPM applications. Aviation gas is for aviation.

Just remember pinging or "Preignition" is different than Detonation.

Detonation can be caused by Preignition but Preignition cannot be caused by Detonation. 2 distinctly different things here.