Here you see the beginning, the tensioner on the left of the chain wheel is respectively a thin wedge, a fat wedge and a roller. The wear is within limits if the fat wedge is less than 6 mm proud of the pressed steel holder, it is 4 mm here, so why does it rattle! The timing is preserved by the two zip ties holding the chain to the cog and my bootlace is supporting the chain so that it does not slip off the crankshaft pulley and lose the timing. Full marks for dexterity, the whole lot was falling apart and I got my lace off my boot with one hand! Only an idiot would proceed further.....