My only input is I found that I bound the flapper valve (central exhaust valve) from pushing the left side bearings too far in. I wouldn't have noticed except I had the jug out doing a topend, then while putting the pv assembly together I bound the flapper. Pulling the bearings back out a mm (ish) solved the issue.
here is a video showing the problem:
http://www.youtube.com/watch?v=FQJs2qM3rT8