This time I changed my oil, when I was finished, I emptied the old oil from the oil pan and discovered an 8mm copper washer. I have already had the engine running and topped up the oil, but discovered no leaks. Can someone tell me where this washer may belong? I'm thinking one of 2 places, Oil drain bolt left side crankcase or oil drain bolt for oil filter. HELP!!!! Can I still use the bike til my next change or will I have to drain the oil and put this washer back on before I ride? Keep in mind that I am getting her ready to be put up for the winter.