I have a 2007 300 XC-W, and  gas pours out the over flow tube. I bought a rebuild kit and it seemed to fix the problem for a couple days. But now it's leaking again. I was hopping the rubber on the float valve was worn. Could the brass seat where the valve rest be worn? And if so is that fixable or is it new carb time? Also if the float height was way off could that cause it to leak gas? Everything I've read says the float height should be 16mm. My float barley reaches 16mm if you pull on it a little.

Thanks

racesla, on 19 September 2012 - 10:44 AM, said:

I suppose anything is possible but wouldn't think the brass seat would be worn, maybe dirty. Did you look at the seat closely when you replaced the needle? The 16mm float height that you mention is for older KTM's that used a different PWK carb. The float height for the stock carb that came on the 07' models is @ 6.5mm. Due to a somewhat extreme angle that the carb is mounted at, some KTM riders change the float height to @ 8mm.

Do you have a fuel filter on the bike? I've had a problem like this on  a guys quad I worked on. I would clean carb and it would work for a few days then start leaking. I found dirt would get stuck and keep it open. So I ended up putting a fuel filter on and it stopped the problem. Another thing that can help fix it is take a drill bit to the brass seat. I always use my fingers and twist it. Since the brass is soft it will just resurface it and take away the grim if it dirty. or a Q tip with fingernail polish remover. The drill bit trick works great though.

hassy,
Glad you said that about the seat. I was trying to wrap my head around how the rubber tip of the needle could wear out the brass seat. A guy in the sevice department at the local Honda/KTM shop told me that. As far as I could see the seat looked fine. Also the 6.5mm on the float height sounds much more in the ballpark to where mine is set at. I'll check it tomorrow. I first noticed the leaking when I was swaping main, and pilot jets. When I would screw the drain plug back on and turn the fuel on the fuel would start to pour out the bottom drain hose, and the one on the right side of the carb. After I would start the bike it would quite. But then I noticed it leaking when I was out riding when I stopped for a sec and I looked down and it was leaking then also. Plus since I got the bike one of the first thing I remarked about, was how bad the fuel economy was. Which makes sense if the fuel is poring out as I ride.

Is there anything beside to high of a float level that would be causing the fuel to flow out the hoses? I thought the bike was jetted kind of odd when I got it. It came from sea level in Texas. I'm at 4,500 feet in Montana so I figured it would be running a bit rich. It had the stock main jet, 40 pilot, but the clip on the needle was on the number one, leanest top position.

Thanks for the info.

No it doesn't have a filter. I did hear about the drill bit trick. I was worried about mucking up the seat.

Thanks

racesla, on 19 September 2012 - 10:21 PM, said:

Its not bad when you do it by hand...since your not putting a lot of pressure it won't muck the seat up or take a lot out. I just do it to take off whatever could be in the way. But get a filter for the extra protection. There is a few times I get a leak right after I get done messing with a carb. I just take a screw driver and tap the carb with the plastic side and it seal the needle...sometimes the float will stick when empty and going to full.

Yeah i didn't even think about the floats sticking. I'll get a filter and a sharp drill bit today.

Thanks

Did you simply try lowering the float level by a mm or two?  Seems like the place to start...

I dropped them down a couple mm yesterday and it was still leaking. I'm going to really take a  close look at everything and make sure the floats aren't hanging up someplace. I did notice there's little bit of junk in the bottom of my gas tank so I'll take the petcock off and give it a good flush.