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Non Resistor Plugs?

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Per NGK

 

Frequently Asked Questions

Q: When should I use a resistor spark plug?

A: NGK "R" or resistor spark plugs use a 5k ohm ceramic resistor in the spark plug to suppress ignition noise generated during sparking.

NGK strongly recommends using resistor spark plugs in any vehicle that uses on-board computer systems to monitor or control engine performance. This is because resistor spark plugs reduce electromagnetic interference with on-board electronics.

They are also recommended on any vehicle that has other on-board electronic systems such as engine-management computers, two-way radios, GPS systems, depth finders or whenever recommended by the manufacturer.

In fact, using a non-resistor plug in certain applications can actually cause the engine to suffer undesirable side effects such as an erratic idle, high-rpm misfire, engine run-on, power drop off at certain rpm levels and abnormal combustion.

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I had read that but I have ran it abit and it has no side effects I can tell. What if I have a resistor plug cap laying around..would that be the same? I just dont need to fry a coil...lol

I got these some time back from a ex pro rider that was cleaning out his gear...I never even thought about the resistor until I read a thread about the R plugs..

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I've ran R type and and NR and never noticed any difference. Bikes ran the same, looked the same, etc etc. At a race I will do a front to rear check of my sons bikes after every moto. I never noticed anything.

 

The only reason I get BR8eg rather than B8eg is because my wifes store stocks them and I don't have to order them. I buy a box of 10

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My experience with this topic is extensive. Noise suppression is HUGE with ignition systems around electronics. It's one of the biggest problems to battle in vehicles with computer systems. Your engine and frame are also great antenna. You may not ever be able to actually feel any difference between the plugs, but your electronics definitely do. The engineers have selected that plug after lots of work, and following basic electromagnetic suppression rules. Your electronics get severely stressed around electromagnetic noise. They may not fail immediately, or ever, but it's not good. This is also the best way to make electronics fail in very strange ways, such as being intermittent. Hard failure modes to diagnose properly. The ignition system is also expecting that 5k resistance there. When it's not , you add current which likely isn't expected by design.

Run the right plug. There is a lot happening without it that you can't see. And none of it is good. Just my .02.

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If I may divert the thread and ask a question to Limagrunt0331:

 

The 1989 - 1994 Kawasaki KDX200 has a United States spec B9ES plug, but the UK has a BR9ES plug.  Do you know why they would be different?  I have wondered this for a long time.  Thank you for sharing.

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The UK and Europe overall have much tighter, and different test procedures than the US. I would assume the R is for added resistance, and EMI suppression to meet their standards. I'm only assuming based off the above comments that the R indeed adds resistance. I'm no expert on the plug nomenclature. The products designed for the UK typically have much more EM suppression compared to the US. Even the test procedure is different. US is typically governed by UL whereas the UK had an entirely different organization, and therefore different test procedures. Even the labs meet different specs.

Just stick to the manual specs unless you know for sure what the differences are.

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