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XR400 Gas Petcock not working

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Has anybody found their gas petcock to malfunction?

I put mine in the 'Off' position and come back to my bike and fuel is running out of the carb all over the place. The valve does not seem to be turning the gas off.

I pulled the tank and sure enough, gas is running right out no matter what position the valve is in.

I'm sure I can replace it, but I was just trying to figure out what may have caused this.

Also, should the carb allow gas to just run right through it so that it dumps out on the ground when the bike is not running?

Thank you

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Don't know about your other questions, but as to your last one, I often forget to turn my fuel petcock off after returning from a ride, and even after a couple of days there is no fuel spilled on the floor or anything leaking from the carb...

In fact, the carb isn't even flooded, because I've hopped on it and it started right up like normal.

Good luck guy.

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When the gas in on/off and you are not running it it should not flow out. You may of just got some things gummed up. Try taking it apart and cleaning everything first. Buy a carb rebuild kit and you'll get all new seals for the carb.

I'd start there and see what happens.

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If it's running out of the vents then your float needle must not be seating correctly. Bike must not run very well?

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Sounds like your petcock is broken or clogged.

As for the carb, sounds like it has a stuck float bowl.

I had that happen once. It just drooled out gas.

I pulled the bowl and cleaned it out.

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Thanks for the info.

I was out in Moab when this happened, I'm wondering if maybe some sand got into my tank. Seems like that would cause both the petcock to get messed up as well as a stuck float. That moab sand is pretty fine, I could see that stuff making it past a filter. Yikes, sand in the motor can't be good!

Well the bike was running awesome the whole time out there. Must have been the lower altitude! Still have stock jetting on this thing and it does not run so well when I'm up in the mountains. Seriously bogs down above seven thousand feet. That will be this winters project.

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when i bought my xr400, the petcock was doing the same thing--leaking gas in every position. i took it apart, and inside is a rubber grommet-like piece with a specific shape designed to let and stop flow in certain positions. I took the piece and turned it around, or upside down (don't remember exactly) but, this solved the problem by relocating the worn part of the rubber to a different place that wouldn't interfere with the function of the petcock. I think we had to drill out and replace some rivets, but that was easy.

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If it's running out of the vents then your float needle must not be seating correctly. Bike must not run very well?

Oh yeah. Forgot to mention the float too. I always forget about that. If you got sand in there you may want to take it apart anyway and clean it out.

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Sounds like your petcock is broken or clogged.

As for the carb, sounds like it has a stuck float bowl.

I had that happen once. It just drooled out gas.

I pulled the bowl and cleaned it out.

yep stuck float bowl, gummed up petcock.......

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