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2003 KX250 - Fouled plugs and spooge - HELP

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Hey everyone, I am having a pretty aggravating plug fouling problem with my bike.  Also, I get a significant amount of spooge come out the tail pipe.  If i clean it, it will be dripping on the swing arm in about 2 or 3 riding hours.  Bike fouls a brand new plug almost always.  Change it, get a ride in, may foul that new plug the next day.  If not, will almost always foul the next time the bike is started.  When it fouls, it will fire, go through a few power strokes and just bog down, game over.

 

Bike info: bone stock 03 KX250, very little use, about 20 woods rides (beginner riding) on the bike.  I use bel ray H1R (have also used MC1) premix, about 38:1.  BR8 NGK plugs.  Has been doing this a long time, ever since the bike had maybe 4 rides on it.  The bike did sit for quite a while in its life, had 90% of the factory tire on it when I got it a year ago.

 

I have taken the bike twice to a reputable bike mechanic here, pilot and needle jets have been replaced.  He said there was a nasty buildup of a chocolate looking gunk in the float bowl.  Crank seal is supposedly good.

 

HELP?  thanks in advance

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forgot to mention, the 2nd time i took it to the mechanic, he mentioned the powervalve was not actuating as well as it should be.  Could this be part of the problem?  Any more symptoms I would be seeing if this was the case?  I do not know a lot about these bikes as you can tell, this is my first.

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  Adjust your air screw out, for highest idle.

  If the problem persists, go to a smaller pilot jet.

Go to Google and search for jetting specs for you year and model, preferably not from Kawasaki.

You should buy a service manual if you are really going to ride this bike.

  Even though you say you have low hours on the motor, the seals go bad just sitting.

  If you have any power loss combined with 'spooge', you probably have a bad crank seal. It is common.

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Thanks for the reply Krannie.  I have some questions based off your responses.  As you can tell, I don't know much about this bike so just wanting to get some more information.

 

 

How would higher idle help out this problem?

Why would a smaller pilot jet help?

I do have the service manual.  I have some mild mechanial aptitude, is replacing the seals something average joe can do with the manual?  Any idea how big of a job that is? 

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The powervalve not being at it's best could be caused by the excessive oil in the exhaust. It tends to gum up the powervalve. It does sound like it's running far too rich. Adjust the air screw towards the leaner end. If it's just at lower RPMs and low throttle opening, it's the air screw, or pilot jet. If it does it at higher RPMs at half to open throttle as well, you've got a bigger problem. 

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What is everyones thought on my fuel/oil choice?

 

I usually run about 36:1-38:1, premium ethanol free, Bel Ray synthetics MC1 or H1R.  Manual calls for 32:1

 

Is my fuel (significantly) too rich?  I know plenty of people run 40ish:1 or even 50:1, but I dont understand why this is so common since the manual calls for way richer.

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You are using the terminology in your last sentence incorrectly.. Less oil equals a RICHER gas concentration. So 32:1 is actually LEANER than 50:1 simply because you have less gas in it. Since you have gone from 32:1 to 36, or 38:1 you have actually INCREASED the amount of gas per tank, and subsequently made the mixture RICHER.

 

The fouling plugs & splooge could be from a mixture that is too rich (jetting is off), or bad internal engine seals allowing crankcase oil to get into the engine side and burn. This happens on Hondas but I can't say it's a problem with Kawasakis as I have never owned one.

 

BEFORE YOU DO ANYTHING ELSE do a leak down test now to confirm that the engine is healthy. This is step 1. If you fail to identify a worn piston/ring and start chasing jetting you could be wasting a bunch of time & money. Only if the engine top end checks out as good, move on to what I have typed below.

 

You can start by measuring your oil level cold and then riding the bike a while and then letting it cool completely and measuring it again checking to see if it is dropping after riding it. If the oil level is NOT dropping, then move on to the jetting. When is the last time you have set, or adjusted, your floats? Floats over time come out of adjustment due to wear of the viton tip on the needle. Over time the floats creep higher & higher within the bowl causing the engine to run richer & richer. Start by checking & setting your floats to the correct level before you change any jets. While you are adjusting the floats remove all of your jets and record the numbers on them. Clean them with carb cleaner and verify that none of the ports, or holes, in them are plugged up. Any blockage, or corrosion, or plugged ports on any jet means you should replace that jet with a new one. Don't try and clean them, just throw them away and put a new one in. If the jets check out okay, put the jets back in, set the floats, then close the carb back up and ride it again. If it is still running rich, you can then start messing with the jets by first going to a smaller pilot jet and or raising the needle clip position. I would only do one of these at a time. Start by dropping the pilot jet at least 2 sizes, then adjust the air screw. When you get the motor running the best it can after adjusting the air screw then you can verify if the pilot is the right size or not. Count the number of turns needed to seat the air screw. If it's more than 3 turns out you are still too rich on the pilot and need to drop at least another 2 pilot sizes. If it is 1 turn or less out from being seated, then you are too lean on the pilot and need to go up at least 1 pilot size.

 

I'm willing to bet that your floats are out of adjustment or your piston and ring are worn excessively.

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Your biggest improvement here will be needle height. The needle is your jetting from off idle to about 3/4 throttle. trail riding is 99% in this range. Try lowering the needle and see if motor gets crisper and spooge starts to decline. You will need to clean your pipe and silencer before the spooge will go away.

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