Question about 2005 KTM EXC 125

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Spark plug fails after two hours of riding??

Bike runs like a dream but after about 2 hours riding the bike may cut out or when its turnd off it will not start again without a new spark plug, spark plug will be black and wet spark plugs im useing are br9es need help!!

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Either you got the wrong type plugs (too cold) and/or that bike is running way too rich! Time to use a tool like ColorTune to get to the bottom of it. Who normally works on this bike? If you don't do the work yourself, then better to take it to a reputable shop/mechanic.

Posted on Mar 18, 2014


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Posted on Jan 02, 2017

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SOURCE: new spark plugs last 10-15 minutes of riding

Hi and welcome to FixYa,

Offhand, the only factor to be checked that could foul a sparkplug for your bike would be the 2T oil injector/pump. There is too much 2T oil going to the combustion chamber. Either the injector would require restricting or for some reason, there is also 2T oil in the fuel tank (pre-mix).

Good luck and Thank you for using FixYa. Happy Holidays.

Posted on Dec 07, 2008

  • 25 Answers

SOURCE: My motox bike is a ktm 250sx 2009 and when i ride

Check the post you submitted yesterday. There are a couple solutions listed for this issue.

Posted on Jun 11, 2009

  • 217 Answers

SOURCE: Black plugs

Black Plugs are indicating that your bike is running too rich(too much fuel to air mixture) you need to have the carburator adjusted,more air.Good Luck.

Posted on Sep 09, 2009

  • 3917 Answers

SOURCE: bike cut out while riding


Check for a clogged filter. You need to clean the carbs.

Please get back to us if you have further query or else please accept this "particular" solution.

Thanks for contacting

Posted on Sep 20, 2011

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