Needle Valve Set or Float out of Adjustment

4 replies to this topic
  • jdswanny

Posted March 02, 2009 - 08:06 AM


I have 01 yzf 426. The carb drips fuel out of overflow hose when the engine is off. THis happened two years ago and I replaced the needle valve set. The carb stopped dripping fuel. The problem is back. I looked at the needle valve set and it appeared to be in good shape.

My question is can the float be out of adjustment and that is causing the fuel to come out of the carb or is it the needle valve set again.


  • grayracer513

Posted March 02, 2009 - 09:36 AM


It can be out of adjustment, but if you think about it, there isn't much way for it to get out of adjustment once it's been set, unless it's been handled somehow.

If the bike sat for a long period, the soft tip of the needle may have dried and shrunk a little, and if that's the problem, it may correct itself after the needle absorbs some fuel and swells back into shape.

One thing that happens rarely is for the float itself to become soaked and heavy. I should say that this hardly ever happens any more because the foam used to make the floats is so much better now.

But dirt is a real possibility. Try opening the float drain and while it's open, turn the gas on. Draining the bowl will let the float drop and pull the needle clear of its seat, and running gas over it may dislodge whatever is preventing the needle from seating.

If you had it apart, you should have been able to check the level setting at that time, but if you haven't done so, and nothing else works, you should probably check it.

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  • jdswanny

Posted March 02, 2009 - 10:12 AM


The problem started again in Jawbone this weekend. I pulled the carb and gave a good cleaning (removed the needle valve set, cleaned and inspected). It stopped leaking for half the day but started again. Could be there was some dirt in it, I removed the dirt when I cleaned it, and then some more dirt found its way back into the needle valve set. I am trying to avoid the $50 for new needle valve set. Jawbone F&*@! my bike up. I managed to rip my pipe off of my bike on one of 12 come offs. Don't know how some of those trails were ever cut.


  • Birdy426

Posted March 02, 2009 - 12:25 PM


There's an O-Ring on the float seat that seals the brass fitting against the carb body. This O-Ring does tend to get old and start to leak. I've had to replace it on both my 426 and my son's 250. Of course you can't get the O-Ring fromthe dealer without buying the entire needle and seat assembly.

You can, however, order it from Sudco. You can also ordeer a new needle without the seat assembly, as witht he rubber tipped needle, the seat almost never wears out. O-ring is about a buck and the seat is about 6 or 7 (but they have a 25 dollar minimum order). I tried to match the O-Ring up at otion Pro, but they didn't have anything close. Your local parts store may be able to order from Sudco without the minimum buy if they have an account. None of mine did...

  • jdswanny

Posted March 02, 2009 - 01:42 PM


Thanks for info. I will give it a try.

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