Since I bought my bike (2005 RM250) I have noticed some pinging. It had some head work and a 265 kit put in by Eric Gorr. Eric said that it will be fine to run on pump gas, so i've be using 91 octane with no ethenal. like i said, though, the bike has been pinging. So today for a Hare scramble i rode in i used some octane booster and the bike rand great (besides getting a little extra oil on the rear fender, but that has more to do with me lugging the bike than with the jetting i think) anyway, i am wondering what octane gas people are using or what people recommend to get the best results. I know there are a few places around here that sell race gas, but i have no experience with it and would like some direction.