NGK bp8evx VS b8es (stock)

The BP8EVX spark plugs foul alot easier than the BR8ES. Unless you have the bike jetted perfectly and consantly make jetting adjustments due to relative temperature, humidity, etc......use a BR8ES. Four BR8ES plugs will outlast 1 "VX" plug for the same price.

-Disclaimer- This is only my personal opinion based on my own personal experiences. I cannot and will not be held liable for any form of fustration due to someone mistaking my opinions as facts. "QUOTE" me at your own risk as throwing a temper tantrum my cause bodily injury or permanent brain damage. I know how people get in this forum!

do a search under ngk or plug. one of the ngk engineers posted a while back saying that under certain engine harmonics the electrode could break off of the plug and cause engine problems. Basically the newer plugs were designed for the newer bikes and yes there is a difference.

Jason

By the way, the P in BP8EVX stands for Projected Insulator. Basically the insulator surrounds, and is flush with, the electrode. The electrode on these plugs are very small. The BP8EVX has a platium electrode (kind of like Iridium or Palladium) which is very thin and has very little surface area due to the insulator. Like I said, they tend to foul pretty easy unless your carb is perfectly jetted.

I believe that the "P" stands for projected tip. Both the tip and insulater are extended. Take a standard plug and a "P" plug and put them side by side. You will see that the "P" plug extends a good 1/8 to 3/16 further into the cylinder. I do not think there is an issue of plug to piston clearance however. Is there a performance increace with a "P" plug? I cant say on my KDX but in my road racer on the dyno the "P" type plug made a small increase in horse power.

Forget about the P plug --just get a B8EV or B8EX. The S plugs have a "standard" wide electrode whereas the V and X plugs have the very thin wire electrodes. These will fire even when completely covered with oil. Imagine a garden hose -open end - and you turn on the water. At 50 psi the wide stream may shoot out 5 or 6 feet. Now, screw on a nozzle with a very small fine hole. At the same 50psi the stream will now shoot out 20 or 30 feet! In electronics, voltage is comparable to pressure, amperage to volume

rvguy: Boy...could I have fun with what you said...but I'd have to be not me ;) (nudge nudge wink wink)

Where'd the 'G' go..as in B8EG? That's a finer wire electrode than the 'S', but not as fine as the 'V'. Costs more than the 'ES', less than the 'EV'. I don't know what an 'EX' is. Also don't know what the designation is for NGKs iridium plug. Ha...maybe 'X'?? :)

I thought there was a considerable difference in performance between the 'ES' and the 'EG', the latter the better. The RB carb is particularly sensitive to, or tends toward loading up on extended lo-rev/lo-load situations. Say, after a long idling downhill you flick-it-quick, you'll be 4-stroking for awhile. The 'awhile' part depends. Maybe for a couple seconds. Too dang long for sure.

NGK says the fine wire plugs will fire easier, under less than optimal situations, say as in the case of the 'total loss' system a dirtbike has (magneto).

It was a combination of reed block/reed change and plug change that virtually eliminated my 4-stroke/load-up problem. Beside that, the pull from right off the bottom of the throttle improved considerably (even before the rad valve came out).

The reason the hose shoots farther with a restriction is the pressure goes up. I don't think putting a fine wire plug in your bike will increase the voltage from the coil. Actually, the reverse may well be true depending on conditions inside the engine. If (as NGK says) the fine wire fires EASIER, that will be with less voltage, not more. The voltage builds in the coil until the field breaks down (jumps) the resistance of the gap in the plug. The point is that the fine wire plug is MORE LIKELY to fire in 'difficult' conditions, and a plug that fires is far ahead of one that don't!

Heck, if I wanted a plug that only worked 50% of the time, I'd ride a 4-stroke!!

FYI...
http://www.ngksparkplugs.com/techinfo/spark_plugs/partnumberkey.pdf

I run a BR8EVX plug I have a 2000 200 and I fouled like 3 plugs the first three weeks I owned the bike . I switched to a BR8EVX and then I havent fouled one yet!! I replaced the last one after a year and I am going to replace this one after another year. Just because... I even loaned my last one out to a cr250 two weeks ago... it still worked! after being in my rear pouch that long..