Race Fuel

[motocross10113]

ok for you guys that are running race gas what kind and octane are you running and is it leaded or unleaded??? Heard not to run leaded fuel in our bikes...and did you change your cdi box or what?? and is it worth the trouble i ride mx and woods c/b rider pending on track

Thanks!

[bigjohn450]

i run vp racing leaded 110 octane in my '04 for three years now and have never had a problem its all stock except pipe and jetting. sometimes i run it straight sometimes i mix 50/50 with 91 octane ive never had a problem.

[motocross10113]

what is the change in preformance?? more over all pull through out the RPM faster throttle repsonse?? i just want to make sure its worth if before i start buy 5-10 dollar a gallon gas...and i here u you have to adjust your CDI box to advance to ignition timing...so you have to get something like vortex?//

[642MX]

I use Monster 110 leaded fuel. Its not harmful. I use race gas for multiple reasons; the lead cushions the valve seats, jetting is easier to dial in, no detonation (I run a 13.5:1 piston), its exactly the same everytime I buy it, and it smells good. ?

[crf-f crf-r trx cbr]

i use pump 94 sunoco ultra-----thats my race fuel of choice

[felix 222]

91 unleaded and it works just fine.

[Kyle Prior]

Im thinking of trying some 100 octane 76 pump gas from the local station. Ill report back after.

[ISBB]

I usually run whatever i can get outta the pump.. sometimes its VP sometimes F&L but usually in the 110 to 111 octane and mix it 70/30 race to pump. ? Have had no problems as of yet and been running this combo for quite some time.. The only reason i did it was for throttle responce. For some reason the throttle just seems to be right there when i need it while runnin the good smellin gas.

[grayracer513]

Race fuels are a benefit because the fuel itself produces more energy when it burns.

Higher octane than the required 95 RON ( about 91 by the R/M averaging method on U.S. gas pumps) is entirely unnecessary for most any YZF, and is of no benefit whatever.

Octane does not provide power, or change anything else about how a fuel burns except its resistance to detonation.

Read from here:

https://www.thumpertalk.com/forum/showthread.php?p=2827893#post2827893

[fish525]

Im thinking of trying some 100 octane 76 pump gas from the local station. Ill report back after.

I run it all the time the bike seams to run a lot cooler with the 100 in it

[Ga426owner]

At least use race fuel developed for a 4 stroke............higher octane is not any benefit......VPU4 is all you need to offer a few more HP and safe for your carb seals. You must however drain the carb after use:thumbsup:

[crf176]

VP U4! Always make sure u drain the carb when ur done riding for the day!

[flintlock28]

If you're running a stock motor, you don't need to use race gas. In fact MXA magazine actually got LOWER horsepower with octanes over 96, compared to 91 octane (R+M)/2 method.

Gas prices are already starting to go back up, and why people want to run expensive gas with stock motors is a mystery to me. These bikes (all the Japanese 250f and 450f's) are designed to run on 91 octane pump gas. Save the money for new tires (they've been going up in price recently also).

IF you switch to a high compression Piston, than you're going to need the higher octane....not on a stocker.

[crf176]

VP U4 is 91 octane plus all the secret ingredients in it to!

[grayracer513]

VP U4 is 91 octane plus all the secret ingredients in it to!

Bear in mind that U4 is either 91 or 92 (depending on which U4) MOTOR octane (MON), which is probably pretty close to 98-100 Research octane (RON), or even higher, and very likely 96+ pump octane (R+M/2). The motor method is much tougher on a fuel, but also much more realistic.