If your engine is brand new it won't run real great until its broken it some but if the plug looks tan at wot then you are in the ballpark. I have a new Dax engine it had 2 base gaskets under the cylinder I think they equaled 0.070 in thickness I made a base gasket that I thinks was 0.050 thick and its improving as it breaks in I'm tempted to mess with the exhaust pipe so it will breath a little better. My neighbor rode it and wants it so bad the can taste it I'll maybe sell him it. I don't need and can't ride 3 bikes. Its a good circus act to ride 2 at one time Bob does a pretty good act doing that when he gets enough O'doulls in him, very entertaining .