Hi guys - I need a little help. I'm going to do an oil change on the weekend and have been told I need a sump plug crush washer. I tried to buy one today but the shop didn't know what size I need and I've searched for the answer to no avail. Does anyone know the size for a GPX250 or the magic words I should google? Also, I got an oil filter that the shop said would fit my bike and it has 2 rubber rings in the box. One large and one small. Is the large one the O ring? Thanks for any help!