I just bought a 99 YZ400. I will never again buy another two stroke!! My question is this: Does anybody use race fuel instead of premium pump gas in their 400/426?? How high of octane fuel can I use without big jetting changes and/or engine modifications? On my old two strokes I used to use a 98 octane race fuel. Fairly cheap but very clean burning (none of those additives that you get at the pump). Is there any benifits to useing a higher grade fuel in this bike or am I wasting my money buying race fuel??

From what I have read the bikes run the best on good old 92 octane. Now Rich Rorich hangs out here and is the most knowledgeable guy I have ever known when it comes to fuel. Maybe he will enlighten us on this issue.


Mike Hetrick

'00 426

'99 Ducati Monster

'73 Kawasaki H1

[This message has been edited by OldFart (edited 04-10-2000).]

Quality pump gas works fine. Gas stored in cans at home loses octane points over time. If you want some "insurance" some of us add one gallon of race gas to 4 gallons of pump gas. I don't claim it works better, but I makes me feel better ;-)


Chris in the Mojave

'98 YZ400F

So long as fuel is stored in *SEALED* cans in a cool place with as little oxygen above the fuel as possible (preferably an inert gas), it can be stored for a relatively long time.

The problem with "Pump gas" is that the tanks are normally vented and some of the more volatile components of the fuel are lost over time, as well as any reaction that may occur with outside factors.

Hence the recomendation that you use gas from a busy filling station (preferrably one that refills it's tanks regularly)

Paul Card

00' 426

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