2008 YZ450F DRD exhaust on the way but I want to order a wash plug now. I measured my stock exhaust hole at 3.5 mm or about an inch and a half. I'm not sure what size the new pipe will be and the plugs have some over lap in size but I'm not sure which will fit best with new pipe. Does anyone have a good fitting plug for a drd exhaust. ( part # 7404).