John
It took me a couple of beers to finally work out how to get the bl**dy drum belt back on, it was always way to long!
Put the belt around the drum and pinch together with the ribbed faces together, release the spring, take the left and right sides of the belt around the right hand side of the white roller, take the belt back around the grooved engine pulley using the slack with the spring released. Replace the spring and the left hand side of the belt will be on the right hand side of the white roller, the right hand side of the belt will go from the engine pulley straight to the drum. There will be no belt on the left hand side of the white pulley.
Hope this makes sense.
Cheers
Paul, April 2008