Try our new info resource - "Aladdin's Cave" (Main menu)Just added a separate link to Ash's Dropbox thread (shortcut)
Adjusting the timing can have no affect whatsover on the tappets, but altering it can make different mechanical noises appear and dissapear, check the exhaust gaskets are not blowing at the head as that can sound very much like a tappet
blowing at the head as that can sound very much like a tappet