Dorman10

It’s like it’s not letting enough fuel flow down to the carburetor, but nothing it’s stopped up from all we’ve tested

Taking apart the carburetor now to see if something from the tank went down in it. The floats in the carb aren’t doing their job anymore because it leaking gas out to the run off hose

Ok so this is going to sound weird, but blowing in the hose to the gas cap seems to keep it running on top end, like it needs pressurizing. 

What would be the ideal main jet for me to use with the set up i have:

440big bore kit

stage 3 hotcam

ported heads.  
slip on HMF pipe

450 had its own cap. I ran it with the cap on and off. Ran it with a bottle too and it still has the issue. Had a vent cut in the bottle and everything. Could it be electrical, like in the stator and firing?

450 tank with a bigger petcock and it’s till starving for fuel. It runs the bowl out in top end

I’m going to put a 450 tank on it tomorrow and see what happens. I haven’t tried actually riding with the gas cap off. Then I’ll try a bottle, and then I’m putting a small fuel pump on it. I have to get this problem figured out

Well guys, the new petcock still didn’t do the trick. I’m still starving for fuel on top end. 😞

I’ll definitely keep y’all posted. Hopefully the new petcock solves it. If not, i have a little fuel pump from Advanced Auto I’m going to slap on there. 🤷🏼‍♂️

But, running it until it shut off and turning the gas off and seeing that the bowl was empty is definitely telling us that is a fuel issue. Thanx for that tip Slammed Ranger

Thanx for all the input guys, i actually went ahead an ordered a new OEM Petcock and I’m going to try that once it comes in. I have a clear fuel line on there so i can see that the fuel is passing through there smoothly and it is not crimped. I ran it on jack stands to watch the fuel run through the line in all gears. 
Shot in the dark, could it be anything electrical or have to do with the fire. I have a brand new plug in it (was doing the same thing with the previous plug). 

I ran it on reserve and on on, each time it cut off i immediately turned the gas off and it’s running the all the fuel out of the bowl

Filter on the petcock looked good. It’s not clogged.  All the screws in the slide arm are tight. I just ran it until it died and turned the gas off. Opened the drain bowl and almost nothing came out 

Yes OEM Honda carburetor. The one i took off was OEM as well, that’s why i got a new one to see if that was the issue 

Yes i have the lid off, that was one of the first things i tried. That’s the only thing I’ve done with the air system 

I need some help guys. I have a 02 400ex with a big bore 440 kit, stage 3 hotcam, ported head, and brand new carburetor currently with a 200 main jet in it, yet it seems like it still running out of fuel on top end. I’ve tried every jet from a 148 to a 200 and I’m having the same issue. It runs good and hard up until I’m going through 4th gear around 60mph and then it just started shutting down like I’m out of fuel. Sometimes if i keep playing with the throttle i can keep it running before it shuts off, but most of the time it just shuts off. It will crank back up without hesitation after about 5 seconds like I’m having to wait for the bowl to fill back up with fuel. There is no black smoke coming out the pipe or anything to show that I’m running too rich. I just need some help, so somebody please tell me what they think is the problem