plug type (to "R" or not to "R", that is the question)

Ok. This may sound dumb but I am no electronics wiz or even amateur but........the plug. WR vs. CR. Resistor plug vs. non resistor plug.

We all know the CR needs the R plug as it has the digital ignition vs. the analog in the WR but many think (formerly including myself) that the WR can run either.

A friend explained it to me this way. The resistor plug came out when the HEI ignitions came out in cars to deal with noise suppression due to the HEI system interfering with electronics especially the car radio. These systems, like the digital systems in a CR run at over 40,000 volts. Thereby needing the resistor. The Analog WR runs at about 30,000, far below and not as hot by about 25% of the CR cousin. Something he mentioned is that because it he WR ignition is not as hot and if you run the R plug, it cannot keep up with the performance it was designed for due to getting less voltage and will eventually carbon up/dirty up over a period of time. (As he explained this I began to think what he was saying could be that the plugs look and performance could be interpreted as a sign of off jetting....hmnnnnn) He also said some stuff I forgot the scientific crap to but the R plug in the analog ignition has the system running through the resistor and doing what resistors do and it also looking for what it is supposed to be resisting but there is nothing there for it so sometimes it may get "confused" ( believe me by this point I was!.......really this guy talks about ohms law and quantum physics when we have a few beers and bench race..jeez.......give it a rest! Supposed to talk about bikes and chicks)

Anyhow I tried a BR9es, then a B9es, then a b9eg, then aBR8es, then a B8es, then a b8eg. Of course there was a little difference between the 9's and 8's as it is still cold here (just a little crisper with the 8) but I did notice the bike liked the non R plugs better with the eg being the best. Really can't pinpoint the eg over the es..........just felt that way.

Point of this is that have some of us WR owners been chasing our jetting due to running an R plug????????? The motors are the same as CR but as previously mentioned, the timings are different and I would suppose the ignition curve is too..

Any thoughts?


Great question. Have been asking this question for years and have gotten no definiatve answer from any one. I think it is a valid issue on the noise suppression for car radios. No one has said but think it has something to do with possibly causing some type of RF interference with the ECU and some of the electronics. One thing I do know is on some of the 125's if the coil wire comming out of the coil to spark plug just dangled and was not run back along the frame support rail and zip tied down, then back to the plug would inadvertently cause the bike to just shut down. ASk my son and Chiodi both were in the final launch mode on a jump when this happened. The symptoms of this are, On the gas hard and just quits, will start back up and seem fine then just does it again at a later time. Was very hard to figure out as it is very inconsistant. Later George

If you go by the owners manual it calls for a "R" plug on the WR. I have run both on three differant WR's and never noticed a differance.

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