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I have a CRF250X and I noticed that there are diff. spark plugs for the X and R. I was wondering, can you use a R spark plug in the X. It seemed like the R plug was a higher performance plug and could possible provide a hotter spark for my X.

I'm getting hooked on improving the performance of my bike ever since I installed the JD jet kit, air box mod, o-ring mod and quick shot. I'm jones'n for another little mod that could give me a little more juice.

Chris

I suspect what you are referring to is a colder vs. a hotter plug. Give us the numbers and we can explain it.
Joe

These are the plug numbers. And all of this is assuming that the plug sizes are the same for each bike. CRF250R: NGK R0409B-8, CRF250X: NGK IMR8C-9H These are the plugs that sparkplugs.com showed as the correct plug for each model.

Chris

I suspect with the weather in NH, you could run the hotter plug. The "R" calls for an 8 heat range, the "X" calls for a 9. As long as you don't overload under high temp scenario, you should be OK with an 8...

It shoudl be noted that the plug probably won't give you any noticeable gains in HP. Might throw your jetting off a little though. So it could have adverse affects.

In case you don't understand, the 8 is a hotter plug and the 9 is colder. As 124 states, neither is going to really change any power at all.
Joe

JAWS wrote:In case you don't understand, the 8 is a hotter plug and the 9 is colder.

Between you and I, we outta write a book on giving missing info! haha.

Thanks for the info. If its not going to do anything for performance, I'll save a few bucks and go with the cheaper plug. Not to mention it took a little while to get everything dialed in with my present setup, so why mess it up.

Thanks again,

Chris