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the 'R' in spark plugs

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Posted by: aharoncross---------------------

hi I have CR-250 1998
I bought B9EG sparkplugs , and the problam is the service menual says I need BR9EG , will it cause demage to my bike if I'll put B9EG???
do you know which kind of bikes uses the B9EG ???
thanks
!!


Posted by: MoO_coW---------------------

R is for resister. It has something to do with protection against your CDI or something I think though. I know several people who have used a non resister plug and havent had any problems.


Posted by: helio---------------------

Now I am using a R plugs to avoid any damage in my ignition...You could also take a look at NGK website in order to learn a bit more about them, or do a good search on this forum about this...you will see alot of thread about this matter.
BTW a R plug only costs a bit more...but replace a ignition will cost alot of money, so I decide to run under safe mode(no differences concerning the power).
Good rides.


Posted by: SprtrxRidr---------------------

So what is the differences (besides physical) between a standard NGK-R and an NGK-IX (Iridium).

Has anybody tried one of these plugs? I want to know if its really worth the $16.


Posted by: MoO_coW---------------------

There have being several threads and pretty much everyone says a regular ngk plug is just as good as the $16 ones.


Posted by: nos96---------------------

I was told that the "R" plugs have resistors, but they are not necessary on a dirt bike, they were made for big bikes like the gold wing that use many different electrical instruments. Mainly, the resistor will help engine noise from interfereing with your electronics like the radio, which you dont have.


Posted by: Chili---------------------

Quote:
Originally posted by Rich Rohrich


I consider it pretty foolish to save a few cents on non-resistor plugs and put you CDI at risk. Of course that won't keep the cheapskates of the world from using them anyway.


The above is a quote from Rich on previous thread. I would tend to take Rich's opinion on pretty much any advice I've seen so far during my short time on this board.


Posted by: biglou---------------------

From the NGK website:

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.


Posted by: Rich Rohrich---------------------

Quote:
Originally posted by MoO_coW
There have being several threads and pretty much everyone says a regular ngk plug is just as good as the $16 ones.


... with nothing but conjecture to back the statement up. :silly:


Posted by: jmics19067---------------------

Rich,
After following your posts about jetting and even taking a stab at your trick question involving plug heat ranges between you and Jeremy. Can I ask why you used an ES plug for your race and an EV plug for Jeremy?

I can understand the importance of heat range and thanks to you know a lot more about how to read it. I also understand the importance of a resisor plug. I can also understand why a precious metal plug would be more expensive but is there any performance to be gained or is it a a bullet proofing issue <the precious metal plug not wearing or eroding as fast> ?


Posted by: Rich Rohrich---------------------

Quote:
Originally posted by jmics19067
Can I ask why you used an ES plug for your race and an EV plug for Jeremy?


On a bike like the CR125 I always keep a box of BR8ES plugs on hand for jetting purposes. Once the jetting is sorted for the conditions the appropriate heat range EVX plug goes back in, unless the engine is really being pushed super hard (odd fuel, extended extreme loads, etc. ) then I'll run an EGV
It has been my personal experience over the years that running an EGV or similar gold based plug buys you a margin of safety when you are trying to tune to the ragged edge. The melting point of the gold center electrode (and good copper core plugs) is very close to the temps seen during severe detonation. If the engine suddenly starts to knock hard enough the center electrode tends to burn out and shut the cylinder down before it does any real damage. It acts sort of like a fuseable link. It's something I learned running air-cooled turbocharged street/drag bikes. It saved a few motors over the years.
The platinum tip in the EVX plugs melts at a temp nearly 1300 degrees (F) higher than the gold or copper plugs so it will hang in and let the engine frag itself before it will stop firing. The upside is the plug will tend to last a really long time in part because of this.

As for performance, on roadrace two-strokes I found the fine wire precious metal plugs seemed to tolerate lean WOT mixtures better. It could be they are just propping up the notoriously cheap japanese OEM ignitions, it's hard to say for sure, but it always appeared to be worth the expense over the course of a race when compared to a standard ES plug. It's a much tougher call with MX bikes because it's been my experience that only about 1 in 20 MX bikes are jetted anywhere near correctly, so small differnces in plug type is the least of most rider's worries


Posted by: NO HAND---------------------

Quote:
Originally posted by Rich Rohrich
...it's been my experience that only about 1 in 20 MX bikes are jetted anywhere near correctly...
:scream: I'm glad to find out my bike is one of those lucky one out of 20 . I'll bet if more riders would spend some time reading here, the dirt bike misery would be less frightening.


Posted by: jmics19067---------------------

Quote:
The melting point of the gold center electrode (and good copper core plugs) is very close to the temps seen during severe detonation. If the engine suddenly starts to knock hard enough the center electrode tends to burn out and shut the cylinder down before it does any real damage. It acts sort of like a fuseable link.

that is awesome information. I mistakingly read more into your other post than the obvious. Use the cheaper plugs to jet and plug readings and then use the expensive plugs to ride/race when you are spot on. While that is rather self explanatory I was wondering <at the time> what was your tuning secret between the 2 different types of plugs<other than the obvious flying right over my head>

Quote:
It's a much tougher call with MX bikes because it's been my experience that only about 1 in 20 MX bikes are jetted anywhere near correctly, so small differnces in plug type is the least of most rider's worries

my experience also but from a completey different perspective ....... but I am learning!!!!!!!!!!


Posted by: Luke Davey---------------------

The 'R' in the plugs means resistor and the sole purpose of it is to reduce electro magnetic inteference which can cause havoc with eletronic ignition and cause car radios to produce static sound due to the electro magnetic signal and the frequency(engine rpm) they are avilable because there are road bikes that use the same plugs as used in dirt bikes. Also silicon cables are used to reduce electro magnetic inteference. The newer NGK plugs have a large blue R on the side to signify a resistance plug


Posted by: derekk87---------------------

i have used non resistors occasionally when thats all i had and didnt have any problems but i run resistors when i can find them



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