2002 YZ426 fuel screw LEAK

4 replies to this topic
  • Vector12

Posted September 30, 2010 - 06:14 PM


Fuel dripping out of the fuel screw. From Sudco I ordered a new remote set up. Spring on the screw, then Washer with the oring on top of the stack.

I looked into the hole, and no extra parts in there. Installed the new setup and it's still dripping. Installed the new spring, washer and oring on my Ziptie Screw and same problem.

I dropped the bowl and the gasket is good.

Just for giggles I put Teflon tape on the screw threads and it still leaked. I'm not sure this is a good idea. ??

I haven't set the float height, and I need to look for a crack or leak in the bowl that leaks into the cavity the screw goes in.

It drips about 1 drop every 4 seconds.

Any quick ideas, I'm sure I'm overlooking something.

I bought the bike with the leak, and a missing o-ring, thinking it would be an easy fix.

The bike runs great, so I don't think the level of the fuel is as high as the small hole where it's really close to the slide.

Thanks guys.

  • mmfowler33

Posted September 30, 2010 - 08:18 PM


I just had the same issue as you on an 03 WR450 I recently bought. I couldn't figure out why it was leaking so I set the float height a couple of times and it still wouldn't stop. I pulled it out one more time and looked in the bottom of the bowl - there was a crack around the small drain screw that was just letting a little gas out. One of the previous owners had evidently overtightened the screw, which cracked the bottom of the bowl. I fixed it with JB weld - but I may just buy a Superbowl or Powerbowl or whatever sooner or later. Anyway, it works well for now, just cant drain the bowl with that screw anymore - gotta use the main drain. Maybe that's the problem with yours too.

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  • William1

Posted October 01, 2010 - 05:07 AM


If the leak is not a crack, then replace the rubber gasket on the bowl. And remove the Teflon tape completely, hopefully none is in the carb threads.

  • GCannon

Posted October 01, 2010 - 07:54 AM


If the Bowl is not cracked. Then carefully check the o-rings on the fuel hose inlet brass elbow that swivels. these o-rings may be leaking and the fuel running along the bowl/carb body mating surface joint and since the carb tilts forward it may appear that the fuel is leaking at the fuel screw.

BTW get rid of that teflon tape on the fuel screw before it ends up in your idle circut.

  • Vector12

Posted October 01, 2010 - 06:50 PM


Thanks guys.

I dropped the bowl again, and the bowl held fuel just fine, nuts no smoking gun.

I got all the teflon tape out, and I swapped out the rubber gasket for the bowl, now no more leak, other one looks fine, but it's not.

I triple checked for cracks, and also checked the swivel.

You guys rock!!

Big Thanks

It did take me 30 kicks to get it started,lol. I was to careful not to flood it, but you still need some gas for the beast to start. Once I got it running I settled the Fuel screw to 1 1/2 turns out and set the idle, now she starts easy, time to get her out in the desert for some plug chops.


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