These wet black rings are the fibre washers that seal the ends of the rocker shafts. They get very hot and are subject to oil seepage from the rocker box.
I need some new ones.
They are not a standard fibre washer - they have a large outer diameter of about 3/4 inch but the hole in the centre is for 5/16 inch - unfortunately they are out of stock at Draganfly:
So here are the bits we need. At the top of the picture there is a 20 mm punch which I have turned from bit of handlebar on the mini lathe. Below that is the special washer and the nut that fastens the rocker shaft in place; top left is the punch used to make the central hole. The new washer is to the left - it's the grey one.
Below is the mangled original.
