what is the difference between the NGK DR7EA, DR8EA AND DR9EA? What do the numbers mean?

 

lower the number hotter the plug
2 hot of plug not good

 

should I try to run the coldest plug possible without fouling?

 

just get another stock plug. They're DRZ250

 

Are u joking about the DRZ250 thing. That is a dirt bike not a spark plug. The choice I have according to the manufacturer are what I posted up above.

 

Id put whatever the owners manual says to put in . The hotter plugs are kind of a band aid for worn motors, which burn alot of oil. If the stock plug fowls out, then the jetting needs to be adjusted.
if you want to know more about plugs, read this article.
spark plugs

 

I was reading this thread and come upon some thing from the NGK website. It was interesting to me, I didn't know that there was a diffrence between manufactures.
from the NGK web site


The heat range numbers used by spark plug manufacturers are not universal, by that we mean, a 10 heat range in Champion is not the same as a 10 heat range in NGK nor the same in Autolite. Some manufacturers numbering systems are opposite the other, for domestic manufacturers (Champion, Autolite, Splitfire), the higher the number, the hotter the plug. For Japanese manufacturers (NGK, Denso), the higher the number, the colder the plug.

 

lol[img]i/expressions/face-icon-small-wink.gif[/img]

 

stay with the stock plug unless you have had motor work done

 

yup, if you start screwing around with spark plus, befor you know it there will be a hole burnt in your piston...