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Was wundering if it is safe running vp racing fuel in my 84 atc 250r. being the 250r is air cool and dnt i want to reck the motor.

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The octane rating of gasoline tells you how much the fuel can be compressed before it spontaneously ignites. When gas ignites by compression rather than because of the spark from the spark plug, it causes knocking in the engine. Knocking can damage an engine, so it is not something you want to have happening. Lower-octane gas (like "regular" 87-octane gasoline) can handle the least amount of compression before igniting.

The compression ratio of your engine determines the octane rating of the gas you must use in the quad. One way to increase the horsepower of an engine of a given displacement is to increase its compression ratio. So a "high-performance engine" has a higher compression ratio and requires higher-octane fuel. The advantage of a high compression ratio is that it gives your engine a higher horsepower rating for a given engine weight -- that is what makes the engine "high performance." The disadvantage is that the gasoline for your engine costs more.

You would be fine running the higest octane from the pump.

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Bot is right it depends on your compression whether or not you need to run race fuel.

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The octane rating of gasoline tells you how much the fuel can be compressed before it spontaneously ignites. When gas ignites by compression rather than because of the spark from the spark plug, it causes knocking in the engine. Knocking can damage an engine, so it is not something you want to have happening. Lower-octane gas (like "regular" 87-octane gasoline) can handle the least amount of compression before igniting.

The compression ratio of your engine determines the octane rating of the gas you must use in the quad. One way to increase the horsepower of an engine of a given displacement is to increase its compression ratio. So a "high-performance engine" has a higher compression ratio and requires higher-octane fuel. The advantage of a high compression ratio is that it gives your engine a higher horsepower rating for a given engine weight -- that is what makes the engine "high performance." The disadvantage is that the gasoline for your engine costs more.

You would be fine running the higest octane from the pump.

Nicely said..:yes:

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All true, octane is resistivity to combustion. Meaning higher octane fuels don't pre-ignite under higher compression. While you don't need to run race fuel you will find advantages. The biggest one being that your motor will run cooler. High octane fuels burn slower and cooler than lower octane fuels. As opposed to lower octane fuels which burn quicker and hotter. However, for optimal performance, I have heard the lowest octane fuel that does not pre-detonate is best.

Edited by DirtDemon

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What everyone said is correct.....I would be more concerned with What Pre-mix you were runnin...Meaning what Ratio....the Leaner the meaner is the way I go....

I think if you have Stock Comp. 91 Octain is fine....The key from here is your Mix.....I think the Factory Sticker on your Trike is 20:1.......On my Trike it is 20:1 but have been known to go 50:1 at times:yes: Regularly I run 40:1....However lots of people run 32:1,,,,I recomend Castor 927

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I have always run 32:1 in all my 2 stroke except my 1981 IT465 I run 24:1

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Whats all your specs on your motor?? If your compression isnt way up there you should be ok with 91 octane... im around 150 psi on my banshee cylinders and im running 91... 32:1 with Klotz Super Techniplate oil...

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Well TPbandit????????? What Say you???? We have mucho Moreo Info to give you if you feel the need for it......You gonna Go VP at 8 Bucks a gallon or 91 at 2????

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i have heard that pump gas is never the same year round like race fuel so it makes it harder to keep tuned correctly.any comments

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I wouldn't think that it be so inconsistent that you would notice the difference.

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have a buddy th@ says that fuel isnt the same as back in the day when the trikes where the thing..:elvis:

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have a buddy th@ says that fuel isnt the same as back in the day when the trikes where the thing..:elvis:

He's right, gas now days is unleaded.

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have a buddy th@ says that fuel isnt the same as back in the day when the trikes where the thing..:elvis:
In the 70's lead content in gasoline was worth talking about. In the early 80's most leaded gasoline was the exact same as the unleaded. Unless you went to a farmers Co-op. The it had lead in it for Tractors. Most insurance companies charged gas stations more if they really sold leaded gas. That is why most gas stations in the 80's sold leaded gas that was really unleaded.

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I remember as a Kid Driving to the airport in my Dads Hot Rod to fill up with AV Gas:yes:

I also remember in the Late 80's Rebuilding that motor to run this Cheap ass Unleaded...:aargh:

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