[chrisu37]

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

[JAWS]

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

[chrisu37]

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

[124]

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...

[124]

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.

[JAWS]

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

[124]

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.

[chrisu37]

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