Spark Plugs

[johnnysneds]

Some useful info on Spark Plugs.

Most dirt bikes will use the "CR8E" rated Spark Plug. Ie WR's, YZ's, DRZ's, KLX's and many many more.
You will also be able to use a "C8E" and are 1/3rd of the price of the aforementioned. The missing "R" stands for resistor and the plugs with these eliminate frequency interference. You should be ok unless you have a TV fitted to your handlebars, but watch out if the better half phones you and your doing 250km/h :

There is also the CR7E and CR89 which refers to the working temperature of the plug. The higher the number the lower the temp of the plug. Make sure you select the spark plug recommended by your bike manufacturer and the gap is correct.
Iridium plugs improve on performance but will burn out quicker than a stocker.

 

[KTMphil]

I just put an iridium plug on the DRZ today, it definitely seems to be running smoother (might just be its a new plug though).

Some useful info on Spark Plugs.

Most dirt bikes will use the "CR8E" rated Spark Plug. Ie WR's, YZ's, DRZ's, KLX's and many many more.
You will also be able to use a "C8E" and are 1/3rd of the price of the aforementioned. The missing "R" stands for resistor and the plugs with these eliminate frequency interference. You should be ok unless you have a TV fitted to your handlebars, but watch out if the better half phones you and your doing 250km/h :

There is also the CR7E and CR89 which refers to the working temperature of the plug. The higher the number the lower the temp of the plug. Make sure you select the spark plug recommended by your bike manufacturer and the gap is correct.
Iridium plugs improve on performance but will burn out quicker than a stocker.

 

[bigntall]

When racing enduros we used to have to run the "R" resistor plugs to avoid eletrical interference to the Enduro computers we ran. I wonder if the electrical charging system without the resistor in the plug can negatively affect a GPS in anyway?? Anyone with insight?

 

[KTMphil]

When racing enduros we used to have to run the "R" resistor plugs to avoid eletrical interference to the Enduro computers we ran. I wonder if the electrical charging system without the resistor in the plug can negatively affect a GPS in anyway?? Anyone with insight?

I've emailed one of the top yacht navigation electricians in the U.S who will get back to me with his opinion on the interference .

 

[Midnitemapper]

[center:6botcp7l]Resistors[/center:6botcp7l]
There is also a resistor built into the spark plug cap on most bikes. It is easily pulled out by unscrewing the bronze cap with the clip connector inside the rubber boot.I sometimes just wrap it with tin foil and replace it or replace the resistor with a solid piece of metal. In many years messing with motors ect, the only interferance I could ever detect is am radio noise.

I have tested many GPS units, and never could detect any interferance while holding the unit next to the plug wire or otherwise. I do isolate my gps power through a converter, on my bike I run 2 Isolated floating ground systems with seperate alternater windings, along with 2 Metal Halide systems.
The metal halide systems start at 23,000 volts equivalent to a spark plug voltage. If that voltage ever got astray it would certainly fry your gps and maybe nock you off your seat!
That is the "starting voltage" for these systems. Once up to temp, (bulb) they usually run on 90V dc.
Running 2 gps units on my bike I am carefull to have then seperated by about 6 inches so they do not interfere with each other.

So I run non resistor plugs, and take out the internal resistor also.
Now my bike is a Kicker! Not really enjoying trying to get er going while bogged in mud or in a river!
I want it to fire first time!
So I want max spark at low rpm, (kickstarting).
Removing the resistors may make it fire in the first rather than 3rd kick, if the plug is dicey that is.
So in marginal condtions the additional voltage may make a difference while starting, (maybe). However up and running, the small additional voltage will never be noticed!

I have rewound my stators magneto windings to increase the output voltage to 150volts ac (at starting) from the normal 90-100v.(output voltage at the plug could have gone from 20,000 to 30,000v?) Of course I opened the plug gap almost double.This was an XR600 which I could easily kick start bare foot!

Most, if not all, small bikes ignition systems are "magneto"and are totally separate from the the bikes charging or lighting system.So if your battery is dead you can just push start your bike, unlike a car whos ignition power is derived from one electrical sytem including a battery. Battery dead no spark, no matter how hard you push a car.

 

[KTMphil]

Spark plug advice from one of the top navigation electricians that works on super-yachts:

"
Well, I'd say that it shouldn't and that most bikes made for the American market wouldn't.
Non resistor plugs and ignition systems that have been even lightly "breathed on" would surely be the exception..
Spark gap ignition generates radio frequency noise much akin to lightning at locally high levels of power.
It can cover large chunks of the frequency spectrum and generate harmonic emissions well out of that frequency range.
So, the answer I suppose is that with non resistor plugs, an aftermarket coil or breaker system, sure there could be interference that could effect GPS reception.
Usually the coil is under the tank and that's commonly 12- 18" from the bar mounted gps..
bikes are very compact in their systems arrangements and can be tricky when trying to resolve interference issues.."

 

[dellboy218]

Don't forget that the leads also play a part in the equation, Carbon impregnated and the wire alternative. A trade off between RFI (Radio Frequency Interference) and resistance with associated energy loss. I agree with the guy on the yacht (I work on somewhat larger yachts up to 320,000 ton) that it shouldnt affect a GPS with the frequencies they use. If one does suffer interference then the first step is to determine whether it is power line derived or via the ''air.'' As most GPS will be running on 5V with a dc-dc converter from the bikes supply it is already isolated to quite a degree. If it is running on its own internal batteries you will have already got your answer. Airbourne interference can be screened out to quite a degree. If the GPS is attached to a plastic mount then (if possible) spray the mount with an electrically conductive paint (I have used a nickel loaded paint in the past) which can then be earthed. Cooking foil is also useful in such cases.
One thing to remember about 'Lectrics and spark plugs. Electrons like to gather on sharp edges and points ready to jump if the air breakdown potential is achieved. They get very lazy on rounded edges!

 

[Steve Canyon]

They may well be a thing of the past soon, there looking at using lasers now...

Wont be very easy to gap them on the side of the road...

 

[dellboy218]

Yes indeed, now that would be something wouldnt it.
http://www.bbc.co.uk/news/science-environment-13160950

 

[Steve Canyon]

Apparently they can adjust the length of the beam to ignite the fuel/air right in the middle of it's mass.....

Not sure I would want a belt of one.. :