Try our new info resource - "Aladdin's Cave" (Main menu)Just added a separate link to Ash's Dropbox thread (shortcut)
It could well be Piki that the chain is overtight, when the engine is just spinning over it's not a huge problem but as soon as the engine starts to load up then the chain does as well, this causes it to overtighten to the point where it's stressing the others parts, the tensioner blade, the chain itself and the guide, even the horseshoe. Not saying this is the case but it's feasible. IF it is this you need to sort it before something snaps, if the horseshoe is stuck you may be able to get it unstuck through the sump, not enough to fix it but maybe just backing it off a little so it doesn't make the chain whine. It will need sorting at some point though, sooner rather than later.
Big problem with all the adjusting is you keep burning your hands on the exhaust, i have put up several times a link to knocks and rattles mod kit for the tensioner bolt which whilst it does not free the horseshoe or make the plunger free is a well made stainless kit to repair the lockbolt and no i do not have anything to do with the firm