I have an old PICCO P60 rear exhaust bought about 10 years ago , I stored it disassembled , and now I don't remember wich way to mount the piston and the rod , because I wonder if the piston has a side that must be in the exhaust position or not , and the rod has a small hole in one side (for lubrification I suppose ) , it must be mounted facing the ball bearing or not ??