Question about 2005 kawasaki KX 250

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I have a 2005 kx 250 2 stroke and it keeps eating plugs

I have tryed diffent plugs br8 br9s and tryed diffent mixs with the fule and 2 stroke am goin to try cleanin tank and fule lines and then try a new plug but if ne one has ne idears plz message me thanxs dan

Posted by eyz69 on

  • Sharky Feb 07, 2012

    I don't know why anyone would be mixing 32:1. This is ONLY for pure mineral oils. If you're using a semi synthetic oil, you can safely mix at 40:1 & if you use a fully synthetic oil you can safely mix at 50:1. I have been doing this for 20yrs & haven't had a single problem with any of my bikes, jet skis, lawn mowers, chainsaws, etc etc etc. Use an iridium plug, at correct plug gap & follow the mixing suggestions I just mentioned & you will have the best performance from your machine.



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NGK brand spark plug BR8ECMVX is the stock plug for the bike. The proper gas / oil mix is 32 to 1. That means 4 ounces of 2 stroke oil per gallon of gas. The posting was not clear as to just what the problem is. If you are burning up plugs there may be a air leak in the intake system making the bike run lean. A lean fuel mix runs hot.

Posted on Jun 25, 2009



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Hey dan, I own a 2005 kx250 also , had a heck of a time jetting the bike to not foul plugs but here's what I did ,lower the pilot or low speed jet to a #48 (stock is #50 ) this will clean up the bottom end and make it a little snappier , If you're going to ride the bike wide open alot like in sand riding you could leave the stock #160 main jet in , If trail riding you'll want to drop to a #158 main jet this is all for sea level to approximately 1500 feet and 60 to 75 degrees, if you ride in 55 degrees and below you'll want to richen up the mixture to stock specs or more ,I'll use a #50 pilot and #162 main jet for 50 degrees and if it gets hot like 90 to 100 you'll probably want to raise your jet needle clip up one clip position (2nd from top is stock) to the notch on top of needle , all of these suggestions are what I use here in Oregon just make sure you're watching the plug color all the time especially when leaning the engine out it should be a light to medium dark brown in color, If it gets leaning towards a white color on the ceramic under the electrode you're in danger of seazing the engine, the last thing is run your premix 32 to 1 with a 50/50 race gas to pump premium ( if you can afford to) and that will help both keep plugs from fouling and prevent pinging of the engine , Also you need to use a old plug that has color on it when you're jetting , that will make it easier to see if your running lean. I'll bet this sounds like quite a hassle but once you get it sorted out you won't be eating $11.00 spark plugs anymore .I hope this helps , I haven't fouled a plug now for 2 years.

Posted on Jun 27, 2009


sean wood

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Put a b7es pulg and run fuel mix 40 to 1 i thinks thats is 250 ml oil to 10 l feul and your air screw2.5 turns out

Posted on Mar 05, 2013

  • sean wood Mar 05, 2013

    check your reed vaules



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You don't always run 32:1. It depends on what king of oil running. If using racing oil most require 50:1. It says it on the back. 32:1 is to much oil and will foul plugs expecially if you do not run it hard. The plugs I always ran were br8es and br9es. Both ngk

Posted on May 24, 2012


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Hi, I have a 2005 kx250 with no spark plug problems 32:1 gas mix ( I use AMS Oil) and a Ngk-br9eix and you should be all set.

Posted on Aug 17, 2010

  • Anonymous Aug 17, 2010

    Sorry that should be a NGK-BR8EIX


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SOURCE: my 1974 250 2 stroke will not start. I have a new

With a bike that is 35 years old lots of things could be the problem. I will list what to look for in a "most likely" sequence but with a mind to some of the easy things to check first.

  • Got gas and is it turned on? Clean air filter?
  • Have a buddy kick the starter while you look for spark.
  • Assuming no spark, How good is your battery? Fuses good? Kill switch on or shorted to the bars or elsewhere?
  • carb, head, intake manifold and carb mounted tight?
  • Does the carb intake manifold have reeds? What condition are they in?
  • I don't recall for sure, does the bike have CDI? If so, have the dealer test it and the coil.
  • If no CDI, when was the last time the points and condenser were replaced or points filed and set? Get the coil checked.
  • Remove the flywheel cover. Take hold of the flywheel and, without turning the wheel, lift the flywheel up and down then left and right. Any movement or was the flywheel rock solid? If movement then the crank bearings need replaced along with the crank seals.
  • Speaking of crank seals, how old are your seals? The bike ain't gonna run with bad seals.
This is a pretty good list of things that should keep you busy for a few hours. Wish I were there to help. It's been a long time since I serviced an old Yamaha 250. I was a shop mechanic for ten years.

Let me know what you find out.
Please rate this answer. Thanks Brandon!

Posted on Apr 02, 2009

ollie reece

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SOURCE: hey! ,i have a 06 kx 250 2 stroke and shes not giveing any fire !

sounds like your coil is packing in try the coil on another bike buddy if this works on another nike get back to me

Posted on Sep 06, 2009



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SOURCE: 2 stroke ratio

32:1 to 40:1 is fine.if you go any more than 40:1 your just wasting money and will foul plugs! any less than 32:1 and the top end is not protected.....

Posted on Jun 10, 2010

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2003 Kawasaki KX 250 keeps fouling spark plugs

Hi, Nicholaswink and the usual suspects are:
1. The first thing to do if your spark plug has been fouled is to check the air filter. If it's really dirty, that makes it difficult for air to get through to the engine, causing a rich condition. Either clean it thoroughly with some Air Filter Cleaner or buy a new filter. Before you put it back in the air-box, treat with some air filter oil or spray. "WARNING" adding too much oil can also clog up the filter, resulting in another fouled plug.
2. While the gas/oil ratio doesn't equate to what the jetting is, you can still foul plugs, or worse, if the mixture is wrong. Depending on your bike, it's best to look at your owner's manual for the correct ratio. For most 2-stroke motocross bikes, a ratio is 32:1 or 40:1, the gas being 32 or 40, and oil being 1. For those that don't it, it means that for every 128 ounces (one gallon) of gas, you add 4 ounces of 2-stroke oil for a 32:1 ration, or just over 3 ounces for a 40:1 ratio.
If you have too much oil in the mixture (such as 12:1), then you will probably end up fouling the plug because it is more difficult to burn that much oil. Don't try to cut corners with the oil though, because it's very important for your dirt bike's engine. 2-stokes need the oil for lubrication on the cylinder walls, so if you don't have enough (or any for that matter) then the cylinder walls will run dry, causing it to overheat and seize the engine very quickly. So it's very important that you put in the right mixture pre-mix to your 2-stroke gas tank.
Also, 2-strokes have reeds that air and fuel go through into the cylinder, so if they are cracked or broken the bike will not run right. This could cause the plug to foul, so before you go out and buy anything expensive, make sure the reeds are still good.
3. While this usually isn't the main problem, it could be that your spark plug isn't burning hot enough. Having a hotter spark will ignite the fuel stronger, leaving less residual gas/oil in the cylinder that could cause the plug to foul. This "ISN'T" the best choice, but I'd say it's safe to go one plug hotter than stock. Keep an eye on the plug color you're looking for a light tan color anything whiter and you could burn a hole in your piston. Spark plug manufacturers aren't always the same, so make sure you find out how they rate them.
4. Almost every motocross bike comes rich from the factory (especially Honda 2-Strokes when they were being made). It's usually a pretty simple fix, but many riders are too lazy and would rather continue buying plugs instead of spending a few bucks on jets.
5. Piston rings badly worn or broken.
6. Faulty ignition coil low output.
For more information about your question and valuable "FREE" downloads that you will need for viewing or printing please click on the blue links below. Good luck and have a wonderful day.
KX 250 Fouling plugs PLEASE HELP
2003 KX250 killing plugs not fouling
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2003 Kawasaki KX250 Owner Manual

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My kx 250 has no compression i put reg gas in and rode i think ran out of gas then tyred to jump it and it siezed up and now i try to kick it over and it gos half way and no compr

If it's a KX it's a 2-stroke and requires oil to be mixed with the gas. If you didn't have a gas oil mix, it is probably seized and maybe even damaged the crank. These bikes have excellent owners manuals that have all the info required to rebuild the motor, and 2 strokes are fairly simple. Good luck!

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I have a 95 rm 125 i keep fauling plugs i mix my gas 40 to 1 and use penns oil 2 stroke mix im using a br9 and a br8 plugs i guess i need a special one but its 35 a plug also my bike when the power band in...

If your fouling plugs, my guess is that your premix isnt quite right and possibly your piston rings are on their way out. BR8/9 should be running your bike fine, we use BR9's in our bikes and we have no proplems. As for your powerband issue, sounds like a jetting problem. Could possibly be a clogged jet. Id suggest stripping the carb and cleaning it out, blow through all the jets, with WD40 or similar so that you know they are free and clear. Put it back together and give it a try.

Mista B.

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differnt brands of oil, suggest different ratios. The oil packaging will give recommended mixes
starting at 25-1 for the cheaper mineral oils, to 50-1 for the more expensive synthetics.

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What is the oil mixture ratio for a 2005 kawasaki 250

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1 Answer

2002 kx 250 2 stroke wont start

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86 kawasaki kx250 rich mix problem

"Learn to like smoke for awhile. Smell the aroma". Pardon the humor. I couldn't resist. Chances are there is oil built up in the crankcase. It is going to take some time for the oil to dissipate. How long? I don't know. It all depends on how much is in there. Cleaning the muffler is no help since the oil burning is coming from the crank not the muffler. If you are careful, and keep a vigilant eye, you could cut the gas/oil mix in half to 64 to 1 instead of the normal 32 to 1. That would mean only 2 ounces of oil per gallon instead of the normal 4 ounces. Let the crank add the rest. This will help burn the crank oil excess, but BE CAREFUL. When the crank drys up you had best not ride until more oil is added to the gas.

A “very helpful” rating for this answer? Thanks!

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