The camshafts are locked into position, using a locking tool, therefore the cams/belt won't move so the bottom pulley is jumping.Originally posted by ChrisB
Why would the belt have jumped a tooth? You have left things tensioned up haven't you? You're just turning the crank which drives the belt as normal. Belt will tension and loosen as the cam lobes compress the springs.
I have just been looking on the net for one of those tools shown above, a few places have them but they say they are for the 1.8 & 2.0