Carb Leaking

[trailrider894]

Recently picked up a 2001 400ex. It was bone stock and had very little use. Carb kept leaking from the overflow so I rebuilt it. That fixed it for a little bit, but the problem returned. It needed to be re-jetted after installed a slip-on so I took it apart cleaned it a little bit and tried again. Still leaks, from both of the drain hoses at times. So yesterday I took it apart again, all the way down to the last bolt. Sprayed out everything I could think of and blew it out with air as well. I also found some fuel in the oil, but that was to be excepted for the situation. So I changed the oil and re-assembled the carb very carefully and was sure to follow the manual to a T. Took it out and rode it for about 30 minutes. It ran fantastic. No sputtering like before and I didn't notice any fuel leaking out or rich symptoms. I decided to let it sit for a few minutes with the petcock on to see what happens and welp, you wouldn't guess. But there it was... leaking from the overflow again. What am I missing here guys? everything inside of the carb is new except for the float and even that has been swapped out between another spare carb I have, (It made no difference).

[400man]

sounds like the float needle valve is worn or still has trash in it? its not stopping the flow of fuel into the carb.

[DragonGunner]

sounds like the float needle valve is worn or still has trash in it? its not stopping the flow of fuel into the carb.


Agree….you need a new needle valve, the rubber tip is worn. Clean in there real good with carb cleaner and q tip also.


Dang this forum has one foot in the grave if not both.

[400man]

Agree….you need a new needle valve, the rubber tip is worn. Clean in there real good with carb cleaner and q tip also.


Dang this forum has one foot in the grave if not both.

yea, its a shame. but there is so much useful info buried in this site, I still search here when I need answers. Although I dont ride as much as I used to a few years ago, Im never giving up on my quads. seems like sxs's have taken over the offroad world, and Im gonna bet in a few more years yamaha will quit making all their sport quads too.

[honda400ex2003]

Id also vote for a bad needle valve (the one connected to the float) or the float is not properly set. make sure the float is in spec when you have it apart. the needle valve should probably take care of it though.

steve