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Z50King said:
avgas is designed for long stints of high rpm. wont really help a dirtbike out




Its also a dry fuel made to be used high up in the sky. If you use it often and dont add marvels mystery oil or somthing of that sort, It will burn up you cylinder. Friends banshee had it happen as it was bone stock and he thought avgas would bump it up.



I run 91 mixed with regular stock car race gas mixed 50/50. When i ran full race fuel it would have a weird RPM curve, But mixed it pulls hard through all gears on my mini or XR600R. I know its not needed, But keeps the carbon from build up. If you have parts that are always clean and wont rob HP, Im just keeping it where it was new and havnt had a problem yet.
 

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I like running a 50/50 mix in my pit bikes they always seemed to run cleaner and smoother.If I run higher than 87 in my street bike it runs worse and always backfires on decelleration.
 

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themountain said:
we tried once avgas instead of our 98...only difference was that the muffler stays clean..thats all!




Av gas octane is rated on a different scale than gasolines intended for ground level use. What is 100 octane "av", is not necessarily 100 octane "ground level".



Besides this, there is also a big chemical difference. Normal ground level race fuels are made up of gas molecules that have a "light end" and a "heavy end". The light end of the molecule ignites easily and burns quickly with a low temperature flame (as a piece of thin newspaper would burn). The heavy end of the molecule is not so easily ignited, but it burns with a much more intense heat (as an oak log would). This heavy end of the gasoline molecule is responsible for the hotter, more powerful part of the combustion process.



Gene
 

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Grafixxs said:
I run air plane fuel in my moped.



Seriously tho, we have ran 89 octane (pump gas) in our 124+R and also Torco in it too, theres no noticable difference in power.
lol i run cumbies(for those who go "huh?" cumberland farms a gas station/minimart) super moto unleaded racing nitro boost 87 gasoline.lol as in regular gas my car uses i dont drive ferarri or anything that will probably be as worthless as its gas in my bike, but anwho the 87 octane works good for me i ran 89 vs 87 even had a little race fuel i dont know what brand it was "borrowed" off my uncles race team at an enduro but it ran the same all the way through. the only diff. was after running seafoam it worked better i use my bikes as A.)daily driver (ct70 to work) b.) beater for trails (ct70 and 86xr100r) and c.) a unofficail race bike for mostly enduro ish type runs (87 xr100r mod.) and not one bike actually even liked the gas other than 89 and 87 octane if the 87 xr might be more race tuned then yeah it might agree better but id go with just using the one that wont ping or detonate.
 

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While running a race gas or high octane(110 or better)...Check your engine temp you will see it lower...No Joke the engine runs easier and will last longer....You will see a performance difference because of this.We always run a 110 Leaded and 93 unleaded to make a smooth run .The RMZ250 my son has,after 66.7 hours on the track still haven't touched the valves and and it runs SMOOTH.
 

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Well something that has never been addressed. Race case is very hard on carb seals. As I have raced my whole life I can atest to this. If you are looking for maintenance then by all means use race gas, otherwise high octane pump fuel is best. And never use 85/ 15 ethenol blend either. Ethanol is hard on seals too. Try to find a station that uses 10 percent methanol during the winter.
 

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i run straight sunoco race gas 110 octane but i liked the 108 octane they had i think it ran the best in my crf250r stock motor. i ran the 98 oxygenated gas that sunoco made but unfortunately i donot remember the results of that and will be buying that after i am through with my 110 octane....however is there any downfall to durability in running straight race gas in a stock motor for big motocross style bikes such as my own
 

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Most of ya'll who say your motor runs better with U4 or any of those other fuel is because of the oxygenation. Simply adding octane to a fuel with not help out a motor that will already run great on Jack Daniel's.



Also 4 strokes dont need octane the way two strokes do.



I ran my 124SE for 3 years on pump fuel with not a single problem, other than a shattered 2 year old piston that the skirt was much thinner than the new one they sent. Also all my 250f's and 525 SX have run on pump fuel with out EVER skipping a beat due to fuel. And my YZ 125 runs solely on pump fuel and Mercury outboard oil And has yet to skip a beat in over 2 years of WFO abuse!



I have tried higher octane fuels and oxygenated and could never feel a difference in power!
 

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Not sure if you have Pilot gas staions in Ma.but they sell a gas they call turbo blue here it's leaded.The RMZ runs like crap on straight turbo blue but if you mix it with unleaded premium it revs faster and runs cooler.Running on premium only,the radiator wanted to spit coolant but with the mix the bike never seems to over heat,and in Tenn. normally we run 20 degs. hotter as an average.
 
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