[Chickenman]

I've exhausted my local resources with this problem to the tune of about $400.00 in labor alone. My Honda 400 Foreman (1996 TRX 400 FW) after a mile or so quits completely or begins to sputter as if starving for fuel. The carburetor has just been re-built, fuel tank has been purged twice and the fuel selector valve on the fuel tank has been checked to ensure it has no obstructions. I have just replaced the fuel lines with OEM hose. It has a new NGK plug and I'm running 93 Octane fuel. I'm beginning to wonder if I have a bad coil and after the machine heats up the coil produces less spark.

 

[misterclean59]

Check the valve lash. I had a Honda XR 250 L that did the same thing. A tight intake valve would cause the engine to loose compression when hot. Hot this helps because it is a free repair!

 

[subzerosoundman]

I am not sure how hard it is to check the valve lash, but it sounds kinda hard to me.
So I would start with looking at the fuel supply by opening the float bowl drain screw
at the bottom of the carb and draining the fuel into an empty water bottle.
Do this first when the engine is off. Then again after it stalls out.
See if there is a difference.