Unsure if an Aprilia Moto 6.5 qualifies as a thumper - but it is a 650 single! I bought the bike (a 1997 model) a few months ago and as yet haven`t got it to start properly. Cold, and with the choke applied, it runs (ticks over) for a few seconds and then dies: it`ll do this forever without actually firing up properly. On removal of the spark plug after the attempts, the plug appears to be dry. It doesn`t sound or feel as though it`s getting enough fuel - it`s as though the bike is trying to be started from cold without the choke. Fuel is getting to the float chamber. All the usual things have either been replaced (HV coil,spark plug HV lead and cap) or checked; wiring, compression, ECU unit etc. The original carburetor, a Mikuni BST40, has been thoroughly cleaned and overhauled with a new float assembly, rubber diaphragm,`O`rings etc. Convinced it was the carb, I replaced it with a new one but the problem still remains. Can anyone help please?