View Full Version : Racing Fuel???

04-15-2002, 09:33 AM
Anyone here use a high octane racing fuel in their 400EX. The manual states that 92 octane or higher should be used but all of the darn fuel stations around me have 91! I found a racing supply shop that carries 105 and 115. Is it safe for the machine to run this stuff? I do not waht to burn anything up!




04-15-2002, 11:27 AM
If your running the stock engine, race fuel will just burn a hole in your wallet. If you have up the compression or have a highly modded engine run the race fuel. I use VP C-12 in mine. It like 108 octane.

04-15-2002, 02:18 PM
Do a 50/50 mix with the 115 and you will have a great running machine.. :)

04-15-2002, 03:51 PM
your bike ownt run better with race gas, race gas burns slower and keeps the engine cooler, this is needed for high compression engines, not stock motors.

besides your jetting will be way off if you decide to use race fuel, (it will run richer)

04-15-2002, 06:05 PM
I use 25% VP c12 & 75% 91 octane pump gas with the mods below. I think that if I didn't have the advance key, I would still be okay w/ straight pump gas.

04-15-2002, 11:34 PM
Excuse me for being a little naive. I am new to this stuff.
What the heck is VP c12 and what does the "Advance Key" actually do performance wise? I apologize if this is a stupid question. Darn Newbies!!! :huh

04-16-2002, 12:23 AM
VP is the brand of fuel (like Mobil or Texaco) & c12 is the type of fuel (go to www.vpracingfuels.com (http://www.vpracingfuels.com/main.html) for more info). The advance key advances the timing of the engine by 6 degrees. This timing advance creates more power but also creates more heat. With the combination of a 10.8:1 compression piston & the advanced timing, I noticed that my engine would ping a little at full throttle. Pinging is caused by too low an octane rating, so I had to mix c12 (which is 108 octane) w/ pump gas (91 octane) to get it to not ping (since pinging or pre-detonation is bad for the motor). Hope that helps & doesn't make things more confusing.

04-19-2002, 05:00 PM
You can use race gas if you want too, but youll just be flushing money down the toilet. 91 octane is good for a stock motor. Dont use octane booster either....just another unworthy expenses for ya.:D

04-20-2002, 12:41 AM
u will go faster from a lighter wallet

04-20-2002, 01:13 PM
Originally posted by 440
u will go faster from a lighter wallet

I'll atest to that!:square

04-29-2002, 12:10 AM
run 91 and let it rip. I've ran 89 before and couldn't tell any difference. My engine is stock inside. I do run 91(premium) all the time unless i'm in a pinch.