02 KX85 Spark Plug

Which plug does it call for exactly. I have an 02 KX125 which calls for BR9EIX irridium plugs. I also run BR8EG's in it which are a little cheaper and work great.

Oh yeah,
Try you r local auto parts store for better deals on plugs, I get them at Murrays.

I'd only use the exact plug if you buy it from the auto store...i have noticed that they don't stock the same plug sometimes and they will check there cross ref book and find one. Well once after using their book they came up with B8ES equivilant in champion..but what i needed was a B8EGV. Talking to the NGK guy he said the B8ES electrodes were falling off in to the cylinder and causing a lot of damage if you let them go too long...thus the new design. And it was only on certain applications due to harmonics.
If you really want to know your alternatives then contact someone like NGK. A lot of engineering work goes in to these bikes and if they could save $10 a bike on the line by using a different plug then I believe they would. It would not really affect the price of the bike just the bottom line which is what they are looking for anyway.

My 03' KX 125 also called for the BR9EIX. I didn't have too much sucess with these plugs, and there were issues with this plug's electrode falling off after using it in there for a long period of time and causing serious engine damage. The plug was also 8 or 9 dollars, so I stopped using it and went to BR8ES's. These plugs weren't much different from what I noticed. I was fouling plugs way too much as it is, since it seems that KXs and RMs are jetted much richer than the CR and YZs stock, so i leaned the jetting a bit and bought the expensive plug that the RM 125 plugs run in a hotter "8" instead of a "9".

Also, a BR_EG series plug will only run $3.50 and may be worth at least consider trying.