Wet Spark Plug

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Mar 29, 2006
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#1
My 04 yz85 won't start. I took out the plug and its wet. I try the old lighter trick and dry it off..put it back in and give the bike a couple kicks. Still won't start. I don't know what to do. Is it just flooded? How do I fix this? Thanks..im the local newbie idiot so there..haha
 

ellandoh

dismount art student
Mi. Trail Riders
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#2
needs a new plug, its permanently ruined. jet it with the info you can find here and this will quit happeneng
 

ellandoh

dismount art student
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#4
til it fouls again, yes if thats all there is to it
 
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#5
so what exactly can i do to stop it from fouling the plugs after i get a new one? -thanks a lot for your help
 

ellandoh

dismount art student
Mi. Trail Riders
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#6
Spanky's jetting guide:

A correctly jetted carb makes a tremendous difference in the torque, midrange pull, top-end pull, and over-rev of your engine. If you have never jetted your bike correctly, you will almost certainly gain some performance at some point in the bike's powerband. A cleanly jetted pilot circuit can be the difference between having to clutch the bike out of a turn or not. The needle can make all the difference in the world for the power of the machine in most situations, as it controls the throttle range that most riders spend most of their time using. A correctly sized main jet could mean the difference between being able to rev out high enough to not have to shift one more time at the end of the straight, or the power falling flat on top and requiring you to make that extra shift.

Are you fouling plugs? Many people will tell you all sorts of band-aid fixes, from running less oil, to running a hotter plug. Both are incorrect fixes for plug fouling. It's all in the jetting.
The only way to know what jetting changes you will need is by trial-and-error. No one can give you jetting specs, because every bike is different, every rider has a different style, and jetting is totally weather dependent. Unless the person telling you what jets to use is riding an identical bike, on the exact same track, at the same time, his recommendations are meaningless.
Jetting is fairly simple, and is a useful skill to learn if you ride a two-stroke and want it to perform at it's best.
It's very important that you start with the pilot circuit. The reason is simple. The pilot circuit affects the entire throttle range. When you are at full throttle, the main jet is the primary fuel metering device, but the pilot is still delivering fuel as well, adding to the total amount of fuel that your engine is receiving.

Before you start to rejet your bike, you need a clean air filter, a fresh plug (actually you need several plugs to do plug-chop tests for the main jet), and fresh fuel. One important detail: Make sure the engine is in good mechanical condition. If your engine has a worn top-end, fix it first. Trying to jet a worn out engine is a waste of time. The same goes for reeds that don't seal properly, and a silencer that needs re-packing. Worn reeds will mimic rich jetting, and worn rings will mimic lean jetting.

Before you start the jet testing, install a fresh plug. Set the float level to the proper specs, an incorrect float height will affect your jetting all across the throttle range.

Warm the bike completely, and shut it off.

As already stated, start with the pilot circuit. Turn the airscrew all the way in, then turn it out 1.5 turns to start. Start the engine, and turn the idle screw in until you get a slightly fast idle, or hold the throttle just barely cracked, to keep the engine idleing. Turn the airscrew slowly in, and then out, until you find the point where the idle is fastest. Stop there. Do not open the screw any farther, or your throttle response will be flat and mushy, and the bike may even bog. This is only the starting point, we will still have to tune the airscrew for the best response.

Now is the time to determine if you have the correct pilot installed in your carb. The airscrew position determines this for you, making it very simple. If your airscrew is less than 1 turn from closed, you need a larger pilot jet. If it is more than 2.5 turns from closed, you need a smaller pilot jet.

Once you have determined (and installed it if it's necessary to change it) the correct pilot jet size, and tuned the airscrew for the fastest idle, it's time to tune the airscrew for the best throttle response. Again, make sure the bike is at full operating temperature. Set the idle back down (the bike should still idle, despite what you read in the Moto Tabloids), and ride the bike, using closed-to-1/4 throttle transitions. Turn the airscrew slightly in either direction until you find the point that gives you the best response when cracking the throttle open. Most bikes are sensitive to changes as small as 1/8 of a turn.

The airscrew is not a set-it-and-leave-it adjustment. You have to constantly re-adjust the airscrew to compensate for changing outdoor temps and humidity. An airscrew setting that is perfect in the cool morning air will likely be too rich in the heat of the mid-day.

Now, it's time to work on the needle. Mark the throttle grip at 1/4 and 3/4 openings. Ride the bike between these two marks. If the bike bogs for a second before responding to throttle, lower the clip (raising the needle) a notch at a time until the engine picks up smoothly. If the bike sputters or sounds rough when giving it throttle, raise the clip (lowering the needle) until it runs cleanly. There isn't really any way to test the needle other than by feel, but it's usually quite obvious when it's right or wrong.

Last is the main jet. The main jet affects from 1/2 to full throttle. The easiest way to test it is to do a throttle-chop test. With the bike fully warmed up, find a long straight, and install a fresh plug. Start the engine, and do a full-throttle run down the straight, through all gears. As soon as the bike tops out, pull the clutch in, and kill the engine, coasting to a stop. Remove the plug, and look deep down inside the threads, at the base of the insulator. If it is white or gray, the main is too lean. If it is dark brown or black, the main is too rich. The correct color is a medium-dark mocha brown or tan.

Once you have a little bit of experience with jetting changes, and you start to learn the difference in feel between "rich" and "lean", you'll begin to learn, just from the sound of the exhaust and the feel of the power, not only if the bike is running rich or lean, but even which one of the carb circuits is the culprit.

The slide is also a tuning variable for jetting, but slides are very expensive, and few bikes need different slides, so we won't go into that here.

Keep in mind, even though this article is intended primarily for two-strokes, four-strokes also need proper jetting to perform right, although they are not quite as fussy as their oil-burning cousins. The only real difference in the two is with the pilot circuit. Two-strokes have an air screw that you screw in to make the jetting richer, and screw out to make the jetting leaner. Four-strokes, on the other hand, have a fuel adjustment screw that you screw in to make the jetting leaner, and out to make it richer.
 

Patman

Pantless Wonder
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#7
Setup the jetting in the carb for your specific location, fuel you use and riding style.You might try droppping the needle one position but doing a throttle chop will be the best way for you to get an accurate read of the plug.
 
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#9
Sounds to me like you're flooded. Turn the gas petcock off, drain the bowl, kick the bike over several times with the plug out to help get the excess fuel out, and put the plug back in and try it. Sometimes you have to take the plug back out and dry it off a few times before it clears out well enough to run.
In the future, make sure that you don't open the throttle at all when starting the bike. I usually open the fuel for a few seconds so the bowl can fill, but I turn it back off until it's running so that if it does get flooded, there won't be more than a bowl full in the crank case.
 
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#10
yzjumperz said:
My 04 yz85 won't start. I took out the plug and its wet. I try the old lighter trick and dry it off..put it back in and give the bike a couple kicks. Still won't start. I don't know what to do. Is it just flooded? How do I fix this? Thanks..im the local newbie idiot so there..haha
The Yz's are jetted horribly rich from the factory. Fouling plugs will be the name of the game until you get it jetted correctly.

For starters you may want to try:

A 135 main
NAPE needle (this is a stock 2005 KX85 needle)
3.5 slide (stock 2005 KX85)
48 pilot

This should get you very close. The most expensive piece will be the slide. You should be able to get the rest of the parts for around $30. The slide helps cleanup right around 1/4 throttle and can be added as finances allow.

The above jetting is what we are currently running at just above sea level. Your optimum final jetting specs may be different.
 
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#11
I have a 2007 Crf 230f i reject my carb yesterday and installed a 130 main and a 45 pilot jet and it seems to run fine but i pulled m spark plug out and on the threads it smells and looks like there is a little gas on it but the tip of the spark plug is completely dry. any info would be nice