my kfx 700 has been running flawlessly and the jetting was right on, however, i decided to use some VP c12 (108 octane gas in it) just to see what it did. when i took it out to test it however it was running lean so i jetted it up and it seemed to run even worse the plugs are very hard to diagnose also(which i just put in brand new to test it with) the outer ring is black (ie rich) and the electrode is a greyish color, not white though. i am drawing a blank and am not quite sure what to do in order to make this thing run right. any one who has used this or any race gas please inform me if you have experience any such difficulties.

 

what mods do you run?

 

the reason you are having problems with race gas is it burns real slow do to octang is much higher so plug look like they are burning rich & lean at the same time the only way i would burn race gas is if you have real high compresion other wise it will run bad

 

You want the center electrode to look almost a dirty white with this fuel. Put some new plugs in it and do a plug check. Almost for sure your too rich. This fuel will look totally different on the plug than pump gas. If you clean your pipe end and ride it, it should look like a dove gray in the pipe.
How did you know it was running lean when you jetted up?

 

Here is more on the topic: I did not write this, or contribute to this, but I know the info contained is correct from my personal experiences. Whoever wrote this knows their stuff IMHO.

http://www.racinxs.com/Technical_Library/VPtuning.htm