andrew empsom on pvw forum is the man to get bits from,if you are gonna do the chains,make sure you change the guides ad tensioners too,might as well do the clutch while you have the gearbox off,oh and the rear main oil seal too.its a nice job to do,but time consuming,try and get the cam locking tool or make one if not,I can photocopy the origianl workshop manual for you if you like for a small fee.