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jetting ?

2984 Views 12 Replies 6 Participants Last post by  t-rex
i was wondering if you jet something what do you all have to get to this this...do you need to new exhaust if you have stock one? and i have a gas leak that is coming from the drain to and it's like pouring out while it's running and off if i don't turn the petcock to off i did just the floater and it's good and i check the vave float to and it was good but i replace it anyways.. so i'm wondering what in the world else it could be while my carb was out i clean it out with carb cleaner to...does anyone have a clue i'm very tired of watching my gas it the ground and wasting my money on gas when i have this leak please help..... oh one more thing what are you guy talking about when you say this "plug test first" how is this done? just wondering to. :icon_ cry::icon_ cry:
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i was wondering if you jet something what do you all have to get to this this...do you need to new exhaust if you have stock one? and i have a gas leak that is coming from the drain to and it's like pouring out while it's running and off if i don't turn the petcock to off i did just the floater and it's good and i check the vave float to and it was good but i replace it anyways.. so i'm wondering what in the world else it could be while my carb was out i clean it out with carb cleaner to...does anyone have a clue i'm very tired of watching my gas it the ground and wasting my money on gas when i have this leak please help..... oh one more thing what are you guy talking about when you say this "plug test first" how is this done? just wondering to. :icon_ cry::icon_ cry:
When you go up in jet size you will be increasing the amount of fuel going to your engine, so you would need to increase the airflow through your engine to keep the air/fuel mixture correct. So, yes you would need an aftermarket filter and exhaust to flow more air. That's where the plug test comes in. You pull your plug out and look at the color of the end of the plug and you can tell if it needs more or less fuel. When the fuel mixture is right it will be a light brown or tan color.

The carb should have a drain hose and an overflow hose. The drain hose has a screw in the bottom of the bowl to close it off. If that is the one that is leaking, then the screw is either loose or damaged or the o-ring is gone off it. If it is leaking from the overflow hose, then your float is bad or your needle valve or seat is bad. I know you said that you replaced the float and needle valve, but if the overflow hose is leaking, it's still got to be the float or needle valve or seat because that's what cuts off the fuel from entering the bowl and yours is not cutting it off. But since you replaced everything, look and see if it's your drain hose leaking instead of the overflow hose.
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sometimes just taking off air lid you have to rejet.plug test is see what color the electrode the white part is.it should be a brownish color.black=rich if its still white its lean.
I think he's wanting to rejet, though. If he's wanting to get any real performance, then he would probably need to get an aftermarket filter and exhaust.
For some reason, I couldn't find the carb at the link you posted, but you are talking about a 400 EX, aren't you? I can't remember, but that carb might use the same hose for the drain and for the overflow. It seems like the drain and the overflow connect together on the inside of the float bowl if I remember right, but I would check the drain screw. Sometimes they leak and fuel will run out the hose just like if the float is bad or stuck open. If you look on the inside of the bowl you should see how the drain circuit connects to the overflow circuit. You might try to tighten that screw up a little. You can see the drain screw in the diagram below.

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If you look on the inside of the bowl you should see how the drain circuit connects to the overflow circuit.
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