Question about 2003 Yamaha YZ 125

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How to clean carb on yz125?

I have a 2005 yz125 and the bike runs well in low to mid power but when I open the throttle there is no power. It feels like the gas cuts off and the bike **** down. What do I need to do to clean the carb? Do I just pull it off and spray carb cleaner? Do I need to double check anything else? Thanks in advance for the help...

Posted by wyser6 on


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ALWAYS have a fire extinguisher on hand when working on carburetors.
Remove the water trap bowl at the bottom of the petcock, (gas valve). Is there any water or trash in the bowl? Drain a cup of gas from the tank. Is there any water or trash in the cup? Dump it, clean it and re-mount it, ( not all bikes have a water trap bowl ).

Drain the carburetor. There should be a large plug on the bottom of the carb float bowl. Remove the plug then replace it after the fuel drains. Turn the gas back on and wait a minute for the carb to fill with gas. If the bike doesn't start and run properly then shut off the gas and remove the carburetor from the engine.

Remove the float bowl and clean the entire carb with a spray carb cleaner from the auto parts store. Wear protective goggles to avoid getting spray in your eyes. Spray into all the little airways and fittings in the carb. Remove the idle screw and the air screw on the outside throat of the
carb and spray into the screw holes as well.
Be sure to put these two screws back in the same hole they came out of. IMPORTANT > do not tighten these two adjusters down. Only screw these in until they LIGHTLY seat. Now turn each adjuster one and one half turns outward. Put the rest of the
carb back together, clean the air filter and install the carb. Let the float bowl fill then start the engine. This process should get you back on the road. Post a comment to get back to me if it doesn't.

A “very helpful” rating for this answer? Thanks

Posted on Jun 16, 2009

  • Jamie Harper Jul 05, 2013

    I did all that already. Do you have any other advice?




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My dirtbike bogs in 1st gear and doesnt idle..then then in high revs it runs great that if a slow down it bogs and shuts off

Posted on Jul 13, 2009

  • mx boy jay Feb 18, 2011

    you need a BR9EG spark plug. that will solve the problem (:



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