You can change to synthetic oil and anytime. If you want cleaner oil from the start, the "Complete Oil Change" thread Glider spoke about basically puts an adapter and hose assy were the oil filter would go, and after filling the oil tank with fresh oil, run engine til last bits of old dirty oil (about 16 ozs (2 cups or so) pumps out clean via clear drain tube into your catch container. The kit is about $130 for most bikes, cheaper on the Dynas because of their oil plumbing is easier and simplier to drain.