03 YZ - NEED HELP BAD - Excessive fuel use

Here is my situation that I have dealing with for several months now. I first noticed that I was using excessive amounts of fuel this summer on rides with my mates. They have CR450s, WR400 and WR450. We are all about the same skill level and when we would fuel up I would take 1.6 gallons to their 0.8 gallons. This was not the situation last summer. I was getting more miles and using the same amount of fuel as they were. I cleaned the spark arrestor screen, air filter and changed the packing in my exhaust (which was jet black). I still was experience the problem. The bike was/is fouling plugs and sounds clogged at low rpms, even after making the above maintenance items. I took the bike to a mechanic who adjusted the valves, which were out a little. The intake being 0.002 from midpoint. He replaced the main jet from the 165 I had in to a 160 (162 being stock) and put in a air fuel mixture quick adjust screw. This still did not resolve the issue. We then went through the carb again checking the float position, jets and accelerator pump. All seem to be in good working order. I am still having the same issue. I did notice a few drops of gas from the head vent tube and the exhaust at idle when pegged is black, but not black when riding. It doesn't seem to run bad just a little clogged at low end and burns double the amount of gas then it did in the past. I don't know where to look next. Anyone have any idea as to what it could be? Could it be the CDI or TPS units.


Check the float level, and the float needle's ability to seal against fuel with only light pressure applied.

I did have the float level checked not sure if the ability of the needle to seal off fuel with a little pressure. How would I check the needle and the seal capability?

Thanks for your support.

Float bowl off, carb upright and connected to the fuel line. Hold the float up against the needle so that it almost, but not quite, compresses the little spring loaded pin in the needle all the way, and turn the gas on (NO cigarettes, sparks, open flames, or hot things nearby!). It should hold fuel from running past the needle seat with that much, or very little more, pressure. If it can't shut the fuel off, it needs to be replaced.

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