Remove both covers lock the powervalve pulley by sticking something through the lining hole. Undo the allen bolt on the right hand side of the powervalve.
After that it'll just pull out. I screwed a spare bolt into the pulley side of the valve then grab that with grips and tug on it. (tap it with a hammer if it's too stiff : The grips i mean not the valve itself :) ) They are usually quite stiff to pull out because of the rubber seals getting dry/covered in crud.
There's two pins inbetween both parts of the valve when they come apart! make sure you don't lose them. (stick something up the exhaust port to catch them incase they fall out of the valve)
Job done.
-- Edited by dtrdave on Monday 13th of September 2010 01:51:55 PM