2000 yz426 smoking alot

7 replies to this topic
  • Mxrider1190

Posted April 09, 2008 - 04:26 PM


I was at my friends house today and he wanted me to try the bike out with the 01 clutch mod. So when I started it it was smoking like my yz125 when I first start it, It did it for about a minute and then went away, I was alot of smoke. then he told me it did the same thing yesterday when they took it out of the basement and fired it up. the oil is'ent over full, and it runs really strong. what do you think it could be??, I was thinking oil could have got in the carb when they carried it up the stairs.

  • grayracer513

Posted April 09, 2008 - 05:38 PM


Usually, when you see oil smoke on startup, but the bike does not continue to smoke after it runs a while it's a sign of bad valve guide seals.

  • BRYANS01

Posted April 09, 2008 - 06:34 PM


i posted on here awhile ago with the same prob., gray said the same thing to me so i changed the valve seals and now no more smoke.

  • Mxrider1190

Posted April 11, 2008 - 05:26 PM


If it is the valve guide seals can he ride it, It doesnt smoke at all when it warms up. when he started it up today it only smoked alittle not nearly as much as before.

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  • grayracer513

Posted April 11, 2008 - 05:33 PM


Yes, if he warms it up and checks the oil level first.

  • DeeCee

Posted April 11, 2008 - 07:33 PM


I suspect the problem will not go away however and will probably get worse. I had a similar issue with my TTR250 recently. It started to smoke on start up and just got worse. I presently have the head and cylinder off to change the valve guide seals and gve it a general top end recondition.

  • grayracer513

Posted April 11, 2008 - 07:44 PM


You're right, it won't fix itself. But he can ride it in the meantime.

  • Mxrider1190

Posted April 11, 2008 - 08:03 PM


thanks, he was hoping he could put it off to the winter.

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