1998 Kdx 200 fuel leaking from carb

[Oscar N]

Hey guys, just bought my first dirt bike, a 98 kdx 200, so I still have a lot to learn but I'm having some trouble with it. My problem is when I turn the fuel valve on it leaks fuel out of the overflow lines. It used to only do it when the engine was off but now it does it when the engine is on too. I have cleaned the carb and I've checked the float needle several times to make sure that it isn't damaged or getting stuck. When I was checking the needle I held it in lightly with my finger and poured some petrol down the line to see if it was leaking and nothing got through. I also checked the float height and it's at 16mm as the manual says. I have no idea what to do next so any help would be really appreciated. Cheers guys

[Davenay67]

How are you checking your float height? Be sure that the float needle is not being depressed at all by the weight of the floats when you take the measurement.

If that is correct, then your float needle and assembly is still either sticking or has some dirt preventing full closure to stop the fuel supply.

[doakley]

Could the float needle be just that worn in an 18 yr old bike but look good to his eye?

[bultaco4ever]

Mine was doing the same thing. A professional mechanic took some scotch bright scrubbing pad and tore it into a small thumbnail size piece. He crammed it down the float needle/fuel inlet and scrubbed the seat area. (use a flat head screw driver or something to swish the pad around) You may have some varnish from old gas that is forming. The seat surface may not be flat. The scrubbing may remove imperfections. It fixed mine.

And start using a fuel filter after you get it fixed.

[Davenay67]

Mine was doing the same thing. A professional mechanic took some scotch bright scrubbing pad and tore it into a small thumbnail size piece. He crammed it down the float needle/fuel inlet and scrubbed the seat area. (use a flat head screw driver or something to swish the pad around) You may have some varnish from old gas that is forming. The seat surface may not be flat. The scrubbing may remove imperfections. It fixed mine.

And start using a fuel filter after you get it fixed.

Mine was leaking slightly too. In a similar fashion to the post above, I took a Q tip and polished the float needle seat with some metal polish. Made sure to get out the polish out afterwards. Super shiny seat and zero fuel leakage afterwards.

[Oscar N]

How are you checking your float height? Be sure that the float needle is not being depressed at all by the weight of the floats when you take the measurement..\

Yes I made sure it wasn't being depressed by the weight.

Could the float needle be just that worn in an 18 yr old bike but look good to his eye?

If the float needle is worn wouldn't it have leaked when i held it in with my finger?

Mine was doing the same thing. A professional mechanic took some scotch bright scrubbing pad and tore it into a small thumbnail size piece. He crammed it down the float needle/fuel inlet and scrubbed the seat area. (use a flat head screw driver or something to swish the pad around) You may have some varnish from old gas that is forming. The seat surface may not be flat. The scrubbing may remove imperfections. It fixed mine.

And start using a fuel filter after you get it fixed.

It could be that because when i got the bike he said that it had been sitting for a year or so and hadn't had much use. When i first took the carb apart there was quite a lot of varnish left from old fuel. There may still be some in the needle seat area as i cant take it out so it is hard to clean it properly, i will try your suggestion and also maybe the metal polish and see how it goes. What fuel filter do you recommend?

[bultaco4ever]

Inline filter. I posted a picture of mine a few days ago. Do a search for the 'Fuel Filter' thread