I just started using Star Tron Gasoline Additive in my new motor....
Amazon.com: Star brite Star Tron Gasoline Additive: Sports & Outdoors
...my next door neighbor has been using it in his 2 stroke lawn mower for over a year and swears by it.
I can hardly wait until my DAX GT50R is fully broken in. As it sits now with my 1-1/2 inch friction drive roller-it hits 35 mph *easy*.