excessive fuel leaking from yz125

6 replies to this topic
  • john15i177

Posted July 02, 2008 - 11:29 PM


i noticed that when i come to a stop and i let my bike run idle, theres always a small puddle of fuel forming beneath my bike. i got off the bike and saw that it was coming from this line...
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i traced the line back to the carburetor, and it goes in right below the tip of my finger here...
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does anyone know whats causing this and how i can fix it? i dont think its normal that my bike is spewing out all that fuel. its mostly when its in idle too. well i guess it might be that i just never notice it while im riding. either way, i hope this is a common issue because i have no idea what to do about this. this is a 2002 yz125.

  • Slackkinhard

Posted July 02, 2008 - 11:42 PM


Your floats are sunk, or your needle has some dirt in it. Prolly the latter...pull your carb, clean it out real good. My guess is you will have to replace the float needle, it prolly has a "ring" indent in the rubber that is not sealing properly.

Good luck!

  • Mikek671

Posted July 03, 2008 - 04:27 AM


As stated take off the bowl and clean everything out real well, when putting it back together also check the float height - if it is not set correctly it can also cause the overflow condition you have. Proper setup for height is shown in the shop manual, simple to check and correct.

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  • john15i177

Posted July 17, 2008 - 02:40 PM


hey guys, sorry it took me a while to get started on this fix. so i got the carburetor out but im not exactly too sure what the proper float height is on an 02 yz125. do i just rip this all apart and just give it a good wipe all around? how do i adjust the float height? and is the float needle that long needle connected to the throttle cable?

float needle?
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  • T-roy JK

Posted July 17, 2008 - 03:33 PM


No, that is not it. In the bottom pic where you are taking the screw out of the float pin. when you remove that screw and pin the float assembly will drop down and the float needle will be connected to the float. the way it works is when the float rises up, it pushes the float needle into the hole and block the gas from comming in. if the top of the float needle looks ok then lower the setting by bending the float assembly to where it pushes the needle a little higher. It only takes a small amount. Your manual should have this in there. use needle nose pliers to bend just the center where it touches the needle.

  • john15i177

Posted July 17, 2008 - 04:08 PM


i took that screw out and the needle looks fine. but what would i actually be bending? i feel like the only way i can bend it is by bending that center pin down a little to drop the needle lower. im assuming that im supposed bring it up. i want the needle to go up if i have a bunch of gas leaking out from the piss tube, right?

haha, man i picked such a bad day to do my first carburetor fix. im trying to go riding tomorrow and i have to work until 11pm tonight. i probably shouldve washed my bike before i started this too.

  • john15i177

Posted July 19, 2008 - 12:10 PM


ok i get what youre talking about now. the tab that holds the float needle up. i pushed it a little ways upward, cleaned all the crap out and threw it all back together. my piss tube still leaks gas, but only when i turn my bike off. but it stops once i turn the gas off. i guess thats good enough, for now. thanks guys

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