Aviation Fuel ?

Does anyone know if using aviation fuel, 100 low lead, is good or bad? I've heard some say that av gas is oxygenated and meant to be burned at high altitude and will not work well at ground level. I've also heard that it can cause heat problems.

People who use av gas say that it works great and is a cheaper alternative to race fuels.

Does anyone have an opinion or knowledge on this subject?


i think eric gorr http://www.eric-gorr.com has an entire article as to why you should NOT use av gas.

at www.dirtrider.net , you can find a virtual plethora of info about av gas. I think what you will find is that av gas won't hurt your engine, but the proper race fuel is better suited. Fuels such as VP C-12 and C-18 are excellent choices as is VP MR1 and MR2. The "C" fuels are non oxygentaed and generally will require leaner jetting while the "MR" fuels ARE oxygenated and require slightly richer jetting. You won't get the benefit of using race fuel if you aren't willing to jet crisp. Don't expect a huge horsepower gain from switching to these fuels. The most important gain here is throttle response. The 426 has a well- deserved reputation of having carburetion glitches. The "BK" mod along with using the proper fuel and crisp jetting gives the best overall return...in my humble opinion.

To say that AVGAS will not work well at ground level is not a very well thought out statement.

Aircraft work the hardest at ground level and although that is not what they do most of the time, it is the most significant event in any flight. If you dont take off, not much of a trip eh?

AVGAS is formulated to vaporize more easily so that it will burn effeciently at altitude but a greay many pilots like to fly one or two thousand feet off the deck. I would venture a guess that far more AVGAS is burned within two thousand feet of the ground than above that altitude.

Because of its low vapor pressure, it has been accused of vapor lock but I dont think this is an issue with a gravity fed fuel system. I know of many people who use it in their bikes and race cars with no ill effect.

That being said, I agree completely that it is NOT the same as race gas and the proper race gas and jetting is BEST but it is a good high octane substitute for pump gas at half the price of many race fuels.

Dave S

Good answer Dave, I had good luck with blending it in my CR250, I have not tried it on my 01426 but I am gonna give it a shot at maybe a mixture of 1.5 gal to 3.5 gal.

Pump gas sux and I can't afford race gas right now, so I'm gonna try it.


I have been running 100LL in my bike for almost a year now and the throttle is definitely a lot more crisper than with pump crap. I ride the bike MX and it never seems to run too hot. Also the engine was just torn apart and the cylinder and piston looked great. Until I can afford to shell out the big bucks for c-12 or c-14 I think I will continue to run it.

:) Joe

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