NGK R6252K-105 replacement?

In my wife's 03 KX100 a BR9** is stock. Because she trail rides and doesn't spend much time at high rpm I put in a BR8EIX. The letters after the number specify the electrode design, ES = standard plug, EG = fine wire, EIX = irridium/super fine wire. I would reccomend the BR9EG for normal MX use.

good luck

bikepilot is right on the money.......

The R6252K-105 was the stock plug in my '99 KX 80 (and I fouled it on like the second ride), and I switched to a BR8ES. I was a beginner rider at the time, so the hotter BR8ES was fine for my riding style. If you're riding it WFO all the time, might want to go with a BR9ES (I even know some top 80 MX riders who run BR10ES's).

Exactly, I also should add that the finer the electrode the more resistant to fouling for a given heat range. That is, a BR8EIX will be more resistant to fouling than an BR8ES. It doesn't run hotter, but the tip stays cleaner and doesn't require as much voltage to spark. I'v run the EG's for years and have found them to be better than the ES's for fouling prone riders (or riding with foul prone riders as the case may be). I just picked up a few EIX's and will test them out this weekend.

enjoy:)

My son just took delivery of an '08 KX85 on Thursday night (9/23), and while breaking it in on Friday we fouled the plug. Its the R6252-105 NGK. I bought two new plugs ($8.99 each) and was told that its common to foul them during the break-in.

Took the bike out on Saturday and fouled the first replacement plug almost immediately upon start up. Tossed the second plug in and my son rode it for approximately 30 minutes (two times at about 15 minutes each). The thing went like a rocket! We were very happy!

On the third time out he takes off and it boggs down and won't rev. Yep, another "done" plug. At this point we're out of plugs so we're done for the day. We were pretty disappointed, to say the least.

I've read this string of postings with interest. I think we need to try the BR9EG plug, based on what I'm reading above. The gas is still the mix that the dealer put in it, so its 32:1.

I heard something today about a "surface gap" plug as being very hard to foul. Anyone run these?

I am sure everybody is or should be riding full size scoots, hopefull 2 strokes by now. You said you were using a 32-1 mix, try 40-1 with a synthetic oil brand. I have been riding 2 strokes for more than 30 years, and I know one thing for sure, you best keep a box full of Ngk plugs, because its the nature of the beast, very high compression and rapid firing wears out spark plugs, period. Buying any new fangled do-hicky spark plug will only result in failure, 30 years baby! Fat center electrode ngk seems to fit the bill, good luck and keep on two smoking!