Following on from part 1 of my carb/ running issues I have now re-built the carb to exact Aprilia specifications. For good measure I replaced the spark plug which is a NGK BR10EG and I also had to replace the battery as mine was dead and wouldn't except a charge, I bought a Motobatt 12N5.5-3B from Busters.
With everything back together the bike fired in to life, ran sweetly and most importantly the carb didn't over flow which points to the float weight all along.
Now that I am happy that bike is running correctly I can move on to some more restoration type jobs.