New NSR 250 MC28 rider.

I think I messed up pretty badly. I used 2 stoke oil that is similar to you use on small engines. After just 3-4 miles, I broke down, I was able to ride it back home in 1st gear on and off. I know I need to drain it and some how flush my oil. What else should I be doing? I've been looking for a service manual on the forums but I can only find a parts manual. Any help will be appreciated.