Question about 2005 kawasaki KX 125

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2005 Kawasaki KX 125 exhaust black smoke

I have a 2005 kx 125. It's running too rich. Shooting black mist out of the exhaust. Looked at carb but don't know what I need to do to lean it out????? @

Posted by wieczorekjoe on


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Gregg Mahin

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  • kawasaki Master
  • 63,339 Answers

Hi, Wieczorekjoe your instrument gauges and lights can alert you to most electrical and engine issues they can not warn you about failed engine gaskets or seals so your engine has to resort to old fashion alert methods of colored "SMOKE SIGNALS" here is a breakdown of their meaning:
1. COLORLESS OR SLIGHTLY BLUE SMOKE on start-up means your air/fuel mixture is the right composition and everything is well burnt in your combustion chamber.
2. BLUE SMOKE on startup is usually caused by failed valve seals dripping oil into the combustion chamber when the engine is not running.
3. YELLOW OR BROWNISH SMOKE at start-up means your air/fuel mixture is too lean. Too lean means that there is low fuel but high air mixture in your combustion chamber.
4. WHITE SMOKE on startup may be caused by a blown head gasket allowing coolant to enter the combustion chamber and may start dripping out of the exhaust pipes or mufflers. Smoke while riding is usually caused by worn out or damaged valves, seals, guides, pistons, rings, or cylinder walls.
5. BLACK SMOKE on startup is usually caused by too much fuel in the combustion chamber this can be due to air/fuel mixture adjustment too rich, accelerator pump improperly adjusted, faulty choke or not in the off position, air filter dirty and clogged, faulty carburetor float needle and seat, pilot jet too large, fuel injectors leaking, smoke while riding is usually caused by the main jet being too large or a damaged carburetor.
It should be noted that aggressive or abnormal throttle operation will cause these conditions to manifest themselves exponentially.
For more information about your issue and valuable "FREE" downloads that you will need for viewing or printing please click on the links below. Good luck and have a nice day.
KX250F Smoking out of exhaust What needs replacement
Carburator Theory and Tuning
OEM Parts for Kawasaki 2005 Kawasaki KX125 Owner Manual

Btw, I’m available to help over the phone in case u need at

Posted on Mar 02, 2018


5 Related Answers


Arnie Burke

  • 6385 Answers

SOURCE: how do i adjust the carb for a lean idle and a

careful please-ajust r for pros specially wen it comes to jets-to lean or to rich can fry an engine-u can do some studying in library sec 629 or purchase books on carb procedures

Posted on Aug 20, 2009


michael schultz

  • 1068 Answers


turn it clockwise. you should by rule of thumb turn the screw all the way in (until it stops) then back it out 1 and a 1/2 turns then start the bike and adjust from that point. it is the best way to do it.

i would take the carb off and clean it throughly to insure no dirt r grim is the cause of the extra fuel.
good luck man

Posted on Sep 23, 2009

SOURCE: how do i adjust my carb for my honda crf 70 its either

To know if it is too rich or too lean or if its ok , you will have to remove the spark plug i.e. after a short run.
If the spark plug is blackish sooty thn its rich, if its totally whitish thn its lean, if is brownish, its ok.

To adjust this you will need to set the air-mixture screw. Tighten it all the way in slowly taking care not to overt tighten it as you may damage the tip of the screw, thn unscrew it 2 &h alf to 3 turns outwards, start your bike's engine and monitor, you may thn go either way alittle to suit the idling.
Best would be to replace the saprk plug.
Hope this helps!

Posted on Nov 21, 2009


  • 3567 Answers

SOURCE: wont idle unless i havethe throttle barley turned

The idle circuit is still plugged up or it would not be giving you this problem. Remove the carb and dis-assemble it then soak the parts in denatured alcohol for 30 minutes. Then use a spray carb cleaner to finish the job. Spray into all the little holes in the carb body. Especially spray into the air screw and throttle screw holes. Reassemble the carb and LIGHTLY seat the air and throttle screws then turn each of them one and one half turns outward. This is the factory setting. Before putting the slide back into the top of the carb, move the clip on the jet needle one notch lower on the needle. This will richen the low end fuel mix. Install a new spark plug and clean the air filter. Please rate my answer. Thanks.

Posted on Feb 09, 2010


  • 57 Answers

SOURCE: carburator is to rich

On bikes since 1980, I believe, the mixture screws are preset at the factory and then the hole is plugged. This is to prevent adjustment for emissions standards (****), and to make you bring it to the shop every time it needs adjustment, so they can "re-jet" your carb, for example, you get new exhaust, or new air cleaner, you are supposed to get it re-jetted. There is even a warning that it is illegal to adjust the carbs. What a load, lol. Anyway, you can drill the plugs out (very carefully, don't want to hit anything important) and adjust the screw. I would only do this if you have checked your intake and exhaust to make sure its flowing freely, and even cleaned your carbs thoroughly.

Posted on May 08, 2010

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dose this carb also have a high/low mix
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I have 1994 fxdl the plugs keep getting caked with black soot and fauling out which makes me believe its running to rich, its also backfiring,thru carb and exhaust, i want to know how to lean it out

Before I can tell you how to lean your carburetor out, I need to know what kind of carb you have. But, there are other possible causes for your problem. The factory usually jets the original Keihin CV carb too lean to meet EPA emission requirements. The most probable cause is running the enricher too long while warming the engine up. The enricher on any carburetor provides an extremely rich mixture. So rich that it will foul plugs if allowed to run for too long. You should only use the enricher long enough to warm the engine to the point to where you can keep the engine running with the throttle grip. Once the engine will run with the throttle grip, simply idle the engine up and use the throttle grip lock to hold the throttle at this setting and push the enricher knob in. Other causes could be that the needle is not seating properly and allowing the carb to load up with fuel. If this is the case, you should have noticed that the engine is idling extremely rich and poorly. In this case, you'll have to at least drop the float bowl off and replace the needle and check the float setting with the new needle. The Kiehin CV must be positioned on an angle to set the float properly. If you still have reason to think that you need to change your carb's jetting, re-post telling me exactly what carb is on your engine.

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Where is the mixture screw on a suzuki 125cc intruder vl 2008, as it appears to be running rich and no manual, plugs get black and wet.

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Were is the fuel fiter

the factory does have a sort of filter that they install on the fuel petcock( on/off fuel switch mounted under tank) but it is a screen( usually plastic) you have to take the 2 screws off and remove the on/off switch to get to it( drain fuel first)......but they hardly ever get clogged!!!! you can check,but i dont think thats your problem...sounds to me like your either running to rich or to lean which will be a carb issue.... do you foul plugs allot?or get a black oily residue leaking from exhaust?( to rich or to much fuel to engine from carb ) if not then sounds like its running to lean.( not enough fuel) ( rich or lean will cause it to bog when hammering on throtle..) if your running lean i would remove carb and clean with carb cleaner( might have a partially pluged jet in the carb.......

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Backfiring on deceleration from exhaust pipes

May be running too lean or too rich. Check the color of your plugs, black dry and sooty means they are rich, white with blisters lean.

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You're either running too rich, or plugs that are too cold.
My first guess, from scanty info: you've changed the exhaust pipes, are running too lean on top (need a different main and maybe needle and cutaway, too) and "fixed" the mixture with as screw on the carb that just adjusts idle mixture.
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What do people mean rejetting? rejetting what ur carb?

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Please see the attached link for your use.

If you do need to replace the jets you'll need to remove the carb(s) and tear in to them abit; the jets themselves just screw in and out. Take care when handling, their brass and can be damaged easily.

I hope this may have assited you,

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