how to read a spark plug

2smokin

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this is different from plug chops even tho he mentions the porcelain thing and treat it like you would a plug chop but its not ... well here you go 1;12 am and i find this hope it helps

Reading spark plugs is a essential part to engine tuning. Selecting the right plug will reduce tendency to knock and be sure that your engine is running in a healthy safe zone.

Reading Spark Plugs

Reading spark plugs is a task most people overlook when finishing the tune on a vehicle but really it is one of the more important things to handle before finishing with the car. A good plug read can tell you what the mixture is like, if the heat range is appropriate, and if there is too much timing (or to little). It is definitely not a replacement for good scanning/datalogging but a better result will be had if you do pair good plug reading and datalogging together.

Reading the ground strap
Reading the ground strap is a easy way to tell if the plug you are using is too hot or cold of a heat range. It will also give you an idea if the timing is too low or high. For timing you'll also want to check the section about reading the porcelain. The general rule of thumb is you want the annealing mark, that is the spot where the ground strap changes color, to be in the center of the bend in the spark plug. Don't go crazy chasing this! I would say if your somewhere between the center plug example and the third example you are in a good area. Note that timing can change the location of the anneal mark but generally its a function of plug heat range first, timing second.

3.jpg

Heat range is too hot! The annealing mark on the ground strap has gone past the bend to the base and has even taken up the first thread or two. Step plug range down at least one step. Timing may also be too high, check section on reading porcelain also.

2.jpg

Heat range is too cold. Annealing mark is just at the tip. Sometimes if the plug is too cold the anneal mark will not even show up on the ground strap. Sometimes in this situation more timing can be used.

1.jpg

Heat range checks perfect. No change needed.

Reading the spark plug porcelain
Reading the spark plug porcelain is a very important step and requires good eyes, magnifying glass, or otoscope. This is to be done with a brand new plug and a full throttle pass or dyno run. It cannot be checked accurately on a plug that has idled or drove around too much. For best results kill the ignition at the top of the dyno pull or track pass. If your spark plug has little black specs all over it that typically is an indication of a slightly too hot plug or a engine that consumes a little oil. The black specs are fuel and oil flash frying on the porcelain. It is not a reason to get too excited unless they are silver or metallic. If you are able to see little silver or metallic dots/specs on the porcelain be aware, that is a indication of detonation. Often you will see signs here before you can ever hear it. Back off timing and also check the ground strap to make sure the heat range is not too high.

4.jpg


Reading the mixture
The last item you can check by reading the plugs is the mixture. This is a tricky thing to do sometimes. Different types of fuel show up differently for example E85 just about not show up at all while some racing fuels will turn orange or rusty looking. The best way to do is is to make sure all forced induction or nitrous engines have a good medium dark shade with normal street gas. A naturally aspirated engine will have a every so slight shade of gray with normal street gas. Typically 93 octane and a high 12 to low 13:1 AFR will just barely start to take a shade of gray. The best way to check your plugs mixture is with a otoscope or by cutting the threads off the plug with a lathe.

The amount of shading and the color are going to depend on the engine and fuel used. Benchmark what you have and work from there.

Note that we are looking at the shading at the very base of the porcelain. The fuel that can be seen with the naked eye is the mixture at part throttle and idle. The fueling that happens at wide open throttle is at the base of the plug only. Also be aware that this is to be done with a brand new plug and a full throttle pass or dyno run. It cannot be checked accurately on a plug that has idled or drove around too much. For best results kill the ignition at the top of the dyno pull or track pass.



6.jpg



Example of a good running spark plug
In the example you will notice that the porcelain is clean and without metallic specs - this indicates that detonation is not present. You will also notice a light shade of gray at the bottom part of the porcelain - this indicates a good mixture. The last thing to notice is that the anneal mark happens exactly at the bend in the ground strap - this indicates that the plugs are not too hot or cold.


8.jpg




heres another again i did not write this ... im just full of curiosity and i hope it answers questions
 
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heres another again i did not write this ... im just full of curiosity and i hope it answers questions




Reading Spark Plugs and Jetting (2-Stroke Only)
I've been getting a few PMs about jetting and how to read a spark plug on a two-stroke engine. Two strokes are a slightly different beast, and are often misunderstood.
First, when it comes to reading two stroke spark plugs, forget most of the charts you see on line. Those pictures are of four stroke automotive spark plugs!
Second, always err on the side of rich, rather than lean! Also, read the next paragraph, and let it roll around in your mind while looking at the rest of this

Two strokes receive all of the engine lubrication through the oil mixed with the gas.
Gas mix ratios are expressed as parts of gas / parts of oil.
For example 32 / 1 or 32 to 1 means you are mixing 32 parts of gas to 1 part of oil. This provides more oil than a mix of 40 / 1 or 40 to 1.
Carburetor jets are a precise fixed orifice, they pass a certain amount of fluid. Jetting is the act of changing that set amount of fluid flow.
This is a hard concept for a lot of folks to grasp, but changing the oil to fuel ratio changes your "jetting" also. The fixed orifice flows the same amount of liquid,
but changing the make up of that liquid effectively also changes the "jetting"!
Keep this in mind, it' will come up again later. But, onto and back to spark plugs!

OK, here goes
These pictures will probably, (almost certainly), be different than what you usually see. Why? Because what is usually shown are four-stroke automotive plugs!

First, let me show you a few different types of plugs you will probably run into, and a few you may never see.
The first, is your "garden variety" standard spark plug, that most of you probably have in your bike:

StandardPlug.gif


You may also see the next kind of plug, the fine wire electrode spark plug. Most of these will be made with an "exotic" metal like platinum, gold, copper, etc. and may be referred to as a "racing plug". They are usually priced a little higher, generally fire better under adverse conditions, but really don't make a noticeable difference over the "standard" plug

FineWireElectrodePlug.gif


The next plug is a multiple ground electrode spark plug. These too are usually a fine wire / exotic metal plug. No real difference over a "standard" plug, but a new twist to improve on firing under adverse conditions.

MultiGapElectrode.jpg


The last plug used to be a very popular "racing plug" when CDI ignitions first came out about 25 years ago. If you do much "vintage" bike restoration, this type came stock on the early Yamaha and Suzuki MX bikes. It's a surface gap or retracted gap spark plug.

SurfaceorRetractedGapPlug.gif




Another thing to watch is reach or the length of the threaded shank of the spark plug. Generally there is three different reaches of spark plugs. If you have any doubt over what you need consult your owners manual, shop manual, or worst case, pull the head and look! Time and money wise, you are way ahead doing that than breaking a piston crown, and risking a bent rod! Here's an example of the different lengths.

PlugReach.jpg



OK, lets look at the kinds of things you'll see while getting your jetting sorted out.

The first picture is of a correctly jetted plug. The center electrode and the bent side ground electrode should be a nice medium to light tan. The outer threaded shell on this plug is just slightly wet, and could use just about a 1/4 turn less air screw, but is looking pretty good over all. If your's looks looks like this, you are 95% there!

NearPerfect.jpg



Next, let's look at some unhappy plugs, some that you are quite likely to see. The first plug is from a very rich engine, that also need the air filter cleaned. Not only is it a wet / sooty black, but it shows a lot of fine dirt that has gotten sucked through the filter. The second plug is also too rich, but is a dryer "sootier" black. I's closer to the correct jetting, but still probably at least 2 sizes too big on the main jet, and could probably use the needle dropped one clip.

CarbonFouled.jpg


WetFouled.jpg



The Next plug you may see too, but not for long. Why? Because it's lean, and too lean on a two stroke means too much heat is being generated. Note: this carb is off all over, the outside threaded shell shows it to be too rich on the idle or pilot jet circuit, but lean on the main jet circuit. You can't really fix this by adding oil (remember that paragraph I asked you to read and keep thinking about) because the extra heat will cook off the oil, resulting in the second spark plug picture. The one coated with melted aluminum from the top of your piston. If this piston doesn't seize to the cylinder wall, there will be a hole melted through the top of the piston, and the bike looses all compression.

RichIdle-LeanWOT.jpg


PartialSiezure.jpg



Something else to consider; plugs have a heat range, a rating that tells you how much heat transfer or retention the plug is rated at. This will also affect your jetting, and give you one more suttle tool to work with.

ColdvsHotPlug.jpg


NGK and Champion plugs have an oposite heat range number system.

NGK Heat Range: Lower number is hotter, higher number is cooler.
IE: BR8XX is hotter than a BR9XX, and a BR8XX is colder than a BR7XX.

Champion Heat Range: Higher number is hotter, lower number is colder.
IE: N2X is hotter than a N1X, and a N2X is colder than a N3X

Heat Range Crossover:
NGK-----Champion
BR7XX-----N3X
BR8XX-----N2X
BR9XX-----N1X

Common NGK Plug Types:
BR8ES or BR8EG = Standard Plug
BR8EIX = Iridium Plug
BR8ECM = Compact (shorter and easier to change)
BR8ECMIX = Iridium Compact Plug


When making jetting changes; first, settle on an oil to gas mix ratio and stick with it! It really doesn't matter whether it's 32, 40, or 50 to 1. Pick a good quality oil you trust, follow the manufacture's mix ratio, then worry about your jetting. Why?

Adding more oil to your gas makes the mixture leaner (more oil and less gas), subtracting oil from your gas makes the mixture richer.
For beginnings, let's assume you motor is jetted correctly. Now, lets assume you jetted that bike using a 38 to 1 oil mix. If you change that mix to 32 to 1 you have leaned out the bike (more oil means less gas) if you change to a 40 to 1 mix you have richen up the bike (less oil means more gas).

When you get your jetting close to that 95% spot, making any radical change can push you over the line from safe and clean to "push it home"


http://www.702sportbikes.com/showthread.php?11233-Reading-Spark-Plugs-and-Jetting-(2-Stroke-Only)

thanks for he info http://www.702sportbikes.com/member.php?180-Supertrunk
 
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Well, if you look carefully at a spark plug, you will notice it has some characters printed on the side.....

Lol, JK, nice going, the more people that learn how to read plugs, properly, the better.
There are books about plugs. When I started 'tuning' and learning how to build performance engines (cars), I saw how in depth plug readings can be!
One can tell almost ANYTHING about the engine state by looking at the plug.
 
heres another again i did not write this ... im just full of curiosity and i hope it answers questions




Reading Spark Plugs and Jetting (2-Stroke Only)
I've been getting a few PMs about jetting and how to read a spark plug on a two-stroke engine. Two strokes are a slightly different beast, and are often misunderstood.
First, when it comes to reading two stroke spark plugs, forget most of the charts you see on line. Those pictures are of four stroke automotive spark plugs!
Second, always err on the side of rich, rather than lean! Also, read the next paragraph, and let it roll around in your mind while looking at the rest of this

Two strokes receive all of the engine lubrication through the oil mixed with the gas.
Gas mix ratios are expressed as parts of gas / parts of oil.
For example 32 / 1 or 32 to 1 means you are mixing 32 parts of gas to 1 part of oil. This provides more oil than a mix of 40 / 1 or 40 to 1.
Carburetor jets are a precise fixed orifice, they pass a certain amount of fluid. Jetting is the act of changing that set amount of fluid flow.
This is a hard concept for a lot of folks to grasp, but changing the oil to fuel ratio changes your "jetting" also. The fixed orifice flows the same amount of liquid,
but changing the make up of that liquid effectively also changes the "jetting"!
Keep this in mind, it' will come up again later. But, onto and back to spark plugs!

OK, here goes
These pictures will probably, (almost certainly), be different than what you usually see. Why? Because what is usually shown are four-stroke automotive plugs!

First, let me show you a few different types of plugs you will probably run into, and a few you may never see.
The first, is your "garden variety" standard spark plug, that most of you probably have in your bike:

StandardPlug.gif


You may also see the next kind of plug, the fine wire electrode spark plug. Most of these will be made with an "exotic" metal like platinum, gold, copper, etc. and may be referred to as a "racing plug". They are usually priced a little higher, generally fire better under adverse conditions, but really don't make a noticeable difference over the "standard" plug

FineWireElectrodePlug.gif


The next plug is a multiple ground electrode spark plug. These too are usually a fine wire / exotic metal plug. No real difference over a "standard" plug, but a new twist to improve on firing under adverse conditions.

MultiGapElectrode.jpg


The last plug used to be a very popular "racing plug" when CDI ignitions first came out about 25 years ago. If you do much "vintage" bike restoration, this type came stock on the early Yamaha and Suzuki MX bikes. It's a surface gap or retracted gap spark plug.

SurfaceorRetractedGapPlug.gif




Another thing to watch is reach or the length of the threaded shank of the spark plug. Generally there is three different reaches of spark plugs. If you have any doubt over what you need consult your owners manual, shop manual, or worst case, pull the head and look! Time and money wise, you are way ahead doing that than breaking a piston crown, and risking a bent rod! Here's an example of the different lengths.

PlugReach.jpg



OK, lets look at the kinds of things you'll see while getting your jetting sorted out.

The first picture is of a correctly jetted plug. The center electrode and the bent side ground electrode should be a nice medium to light tan. The outer threaded shell on this plug is just slightly wet, and could use just about a 1/4 turn less air screw, but is looking pretty good over all. If your's looks looks like this, you are 95% there!

NearPerfect.jpg



Next, let's look at some unhappy plugs, some that you are quite likely to see. The first plug is from a very rich engine, that also need the air filter cleaned. Not only is it a wet / sooty black, but it shows a lot of fine dirt that has gotten sucked through the filter. The second plug is also too rich, but is a dryer "sootier" black. I's closer to the correct jetting, but still probably at least 2 sizes too big on the main jet, and could probably use the needle dropped one clip.

CarbonFouled.jpg


WetFouled.jpg



The Next plug you may see too, but not for long. Why? Because it's lean, and too lean on a two stroke means too much heat is being generated. Note: this carb is off all over, the outside threaded shell shows it to be too rich on the idle or pilot jet circuit, but lean on the main jet circuit. You can't really fix this by adding oil (remember that paragraph I asked you to read and keep thinking about) because the extra heat will cook off the oil, resulting in the second spark plug picture. The one coated with melted aluminum from the top of your piston. If this piston doesn't seize to the cylinder wall, there will be a hole melted through the top of the piston, and the bike looses all compression.

RichIdle-LeanWOT.jpg


PartialSiezure.jpg



Something else to consider; plugs have a heat range, a rating that tells you how much heat transfer or retention the plug is rated at. This will also affect your jetting, and give you one more suttle tool to work with.

ColdvsHotPlug.jpg


NGK and Champion plugs have an oposite heat range number system.

NGK Heat Range: Lower number is hotter, higher number is cooler.
IE: BR8XX is hotter than a BR9XX, and a BR8XX is colder than a BR7XX.

Champion Heat Range: Higher number is hotter, lower number is colder.
IE: N2X is hotter than a N1X, and a N2X is colder than a N3X

Heat Range Crossover:
NGK-----Champion
BR7XX-----N3X
BR8XX-----N2X
BR9XX-----N1X

Common NGK Plug Types:
BR8ES or BR8EG = Standard Plug
BR8EIX = Iridium Plug
BR8ECM = Compact (shorter and easier to change)
BR8ECMIX = Iridium Compact Plug


When making jetting changes; first, settle on an oil to gas mix ratio and stick with it! It really doesn't matter whether it's 32, 40, or 50 to 1. Pick a good quality oil you trust, follow the manufacture's mix ratio, then worry about your jetting. Why?

Adding more oil to your gas makes the mixture leaner (more oil and less gas), subtracting oil from your gas makes the mixture richer.
For beginnings, let's assume you motor is jetted correctly. Now, lets assume you jetted that bike using a 38 to 1 oil mix. If you change that mix to 32 to 1 you have leaned out the bike (more oil means less gas) if you change to a 40 to 1 mix you have richen up the bike (less oil means more gas).

When you get your jetting close to that 95% spot, making any radical change can push you over the line from safe and clean to "push it home"


http://www.702sportbikes.com/showthread.php?11233-Reading-Spark-Plugs-and-Jetting-(2-Stroke-Only)

thanks for he info http://www.702sportbikes.com/member.php?180-Supertrunk
 
This is my plug after about 2 hours riding, can anybody give me any info about it. View attachment 9708
It all depends on a lot of variables.

Was the engine idled for a while before removing?

Are you oil injected?

Was the run prior to removal WOT or somewhere on the needle.

What oil do you use.

As an example, I run Maxima 927 or Castrol R30 at 25:1, a slightly rich mix, and if I removed my plug After idling for a few seconds from a hard WOT run, it would be wet and as black as the Ace of spades.

The recommended way to ascertain jetting from plug condition is with a plug chop.
 
very nice wording blaaster
I did the plug chop,brand new plug, ran through gears 1-6 full throttle, pulled clutch while still wot and hit kill switch, then rolled to a stop and pulled plug, bike was fully warm, and plug still looks almost brand new with a VERY faint tan line. Also seems to bog down a little around 2nd gear at 1/4 throttle and past that it runs strong and fast, trying to upload a video from my phone of riding it. top picture inside of plug is only dirty from trying to cut with hacksaw by hand (dirt), second picture is after the WOT run^
20140425_234133.jpg
20140425_231855.jpg




Amsoil double foam air filter. stock air box with cover on, stock mikuni carb, air screw 3 even turns out(where it runs the best) gold series fatty fmf power core 2 silencer, tors is bypassed (removed the tors black piece out and run with my own idle screw in it), main jet 230, pilot jet 35, boyesen power reeds dual stage(two flaps), 93 octane gas, need to know where to go from here with what my plug looks like and what is done to it.
 
Looks lean!

Set the float level.

Needle in the middle slot.

Adjust the idle as per specs, 3 turns out on the air screw is excessive if you have the stock 32.5 jet in there.

Try a #280 - #290 main and chop again.
 
Looks lean!

Set the float level.

Needle in the middle slot.

Adjust the idle as per specs, 3 turns out on the air screw is excessive if you have the stock 32.5 jet in there.

Try a #280 - #290 main and chop again.
35 pilot jet auto oil mixer still, 3 turns out seems to be where it runs best.
 
ditch the auto oil injector .. {will save you big headaches in the furure} its very simple to do
http://www.blasterforum.com/threads/how-to-remove-oil-injection-without-a-block-off-kit.3272/

but after you remove it premix you gas and oil preferably to 32:1
and yes you look lean with an aftermarket pipe you should not be at a 230 whatsoever{plug chop every time you change anything regarding exhaust/intake}
i would not ride the bike{until you jet correctly} for fear of running to lean and seizing it up {by by topend}
follow blaasters info 280 and plug chop your way down
as for that 35 pilot ...hmmmm im not sure if you wanna keep it and run 3 turns out or go down to 32.5 and 1 1/2 turns out { i believe either will work}
 
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