Question about 2003 Yamaha YZ 125

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Tons of smoke coming out of exhaust

I have a 2003 yz 125 new bottom end new top end i took apart and i cant find anything wrong it starts up and blows smoke like we are BBQn new air filter new plug still smokes really bad can u help.

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  • 2,050 Answers

A bad crank seal on the right side, if bad, will **** transmission oil into the combustion chamber. This will smoke badly.

Posted on Jul 16, 2010

  • Mista B Apr 07, 2011

    Yep aggree with dmsr63, right hand side crank seal will probably be shot. Either that or you have seriously overloaded your pre mix lol. Right crank seal seems to be a problem on the YZ, had 3 go quite recently on 3 different bikes.

    Mista B.



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I asked a question yesterday about my 125 seizing up; well today i tore apart the top end and all looks good ,can't find anything wrong no metal shavings or scaring in the barrel, any advice? The motor...

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My blaster 200 is blowing alot of white smoke

I agree, Too much oil in the mix. I run at 40:1 at the moment but have also used 50:1 in the past with no problems.
Drain the fuel tank and re-fill with fresh 40:1 mix.
Tip the bike over on its side to run out the carb.

Good Luck.

Jun 30, 2009 | 2003 Yamaha YZ 125

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