Motorcycle Repair: Carburetor Problem ?, honda ct 110, needle valve

Question
Hi Chris
I have an old 82 Honda CT 110 Trail Bike . The bike runs with the Choke open at idle but if I       
accelerate rapidly while riding the engine will die or cut out . If I close the choke while  riding , the bike will run with out cutting out and pick up speed and run almost normal but when I slow down to idle the engine will die . I have cleaned out the carb , soaked in it carb cleaner over night , blew out the ports and holes w/ air pressure , cleaned the carb screen , put in new gas , ck'd the fuel lines for obstuctions cleaned the tank and at this point I am lost, the bike still does the same thing even after doing all of the things that I did .The spark plug is new , I took it out after a few miles and it is black.. to much fuel I guess ( Not Good ) .Is my problem a carb jet problem or what ? Any help with this problem would be much apreciated ...
Thanks much , John ...

Answer
Hi John.
 Have you checked the needle valve to see if it fell out of it's guide or perhaps that it may be set to run too rich.

If the needle valve is still in the slot, then set it to the other guide mark that is on the needle.  It could be set too rich.

There is also the possibility that the main jet is set too rich.  If everything else is correct or has no affect on the way the bike runs, then lean out the mixture 1/4 turn at a time till it runs correctly.

Let me know what happens.
Good luck.
FALCON