Try putting the spark plug gap to as little as 4mm , this will may it easier for the ignition to provide a spark. When you poured the petrol into the spark hole , did the bike fire? You said you have cleaned the carburetor , if it is a Dell'orto it is possible you have installed the floats upside down. Check that the high tension spark plug lead is connected to the spark plug cap correctly. If it is a resistor type plug cap , it may be faulty. Good luck.