Motorcycle Repair: 96 rebel 250 carb problem, rubber compounds, honda rebel

Question
i have a 1996 honda rebel and i believe it is having carb problems. i can ride it occasionaly but after it warms up it starts running like crap. i will be going down the road and it will act as if i just pulled the clutch in. it looses all power. once i get to the side of the road and i pull the throttle it tries to die. it kinda acts like it isnt getting any gas. i have completely pulled the carb apart, cleaned it (a lot of black soot came out of it). replaced the old spark plugs and did an oil chance on it. sometimes i could just let it cool off and it would start right back up and it would run good again. yesterday i had to pull the filter off and after that it ran a whole lot better. than today i was on my way to class and it acted up again and this time i couldnt get it started. what the heck is up with it. i am about to sell it if anyone is interested. i am getting so tired of the non-reliability. any suggestions? how can i fix this problem?

Answer
Carolina, Two things may be happening. There is a black rubber packing in the fuel valve on the bottom of the tank that can break down and cause debris in the carb also the black fuel lines from the tank down to the carb can break down causing problems in the carb. Because there is no fuel filter installed at the factory and the fuel we are getting now can mess with the rubber compounds in the fuel line makeup. Even if you add a filter in line there is still the old line from the filter down to the carb. See if you can replace the lines and inline filter drain the carb of old fuel and see if it runs better.