YZ250F spark plug

[zcookie49]

Just a quick note. My owners handbook states to run NGK CR8E spark plug, which I do... I received the Yamaha off-road accessories catalog, and in the rear it states that the 400-426F run the CR8E and lists the 250F to run a CR9E?
I follow the manual, but would running this higher number plug provide any difference? Or is it just a hotter running plug? Anyone heard of this? It's in the Yamaha GTY-R catalog, 2001.

 

[Rich Rohrich]

The CR9E is a colder plug. It's designed for sustained high load high rpm running, like in the desert or dunes. It's unlikely to be necessary for normal MX use.