Help me see the obvious...please

6 replies to this topic
  • Goosedog

Posted June 12, 2007 - 05:11 PM


OK, so I went to do some simple carburator maintenence on my YZ426 tonight and now it won't start.

The task was replacing a worn out needle and emulsion tube with new OEM parts. My bike's got some considerable hours on her and it was getting near impossible to lean it enough with a worn out tube and needle.

After a simple switching out of parts I re-assembled and went to test joy. I scatched my head for awhile and decided to put it back as it was knowing those new parts couldn't have killed the bike but had to be sure. Still, no fire but an occasional pop.

I really just need a fresh set of eye's to see whatever it is I can't, figuratively speaking of course.

  • kxman

Posted June 13, 2007 - 08:03 AM


You had the slide out didn't you? The thing doesn't go back in like it looks like it should. If that isn't it I don't know.

  • Goosedog

Posted June 13, 2007 - 01:55 PM


You had the slide out didn't you? The thing doesn't go back in like it looks like it should. If that isn't it I don't know.

Nope, you don't need to pull the slide out to change the needle and the e-tube accesses from the bottom. My latest guess was that by tilting the carb 45deg, I might have pulled a wire loose with the throttle cables but that's not it. I'm going :thumbsup: here trying to figure this one out.

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  • onecolumbyte

Posted June 13, 2007 - 04:28 PM


My guess would be fuel screw. You didn't say but I'd start there.

Also, check your coil. I almost always have to remove it to get at the carb and the first time I didn't tighten it back up. Gave me fits trying to start it with no spark.

  • yz_for_me

Posted June 14, 2007 - 01:16 PM


Make sure you got a good seal around the carb boot. I know when I've turned my carb to make an adjustment, sometimes the boot doesn't quite seal right when you turn it back.

  • 642MX

Posted June 14, 2007 - 03:17 PM


Are you sure you didn't flood it which may have fouled the plug? If you have an extra plug, it maybe worth a shot.

  • Goosedog

Posted June 14, 2007 - 04:13 PM


This morning I took it all apart again and re-assembled very slowly and methodically and low and behold she fired right up.

I had checked the coil ground, flooded bowl, fouled plug and fuel screw theories (thanks) but believe in the end it was the cylinder side boot that didn't get sealed properly due to haste.

Leason learned, take your time and do it right...but man I hate those gremlins that sneak by your logic. :thumbsup:

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