What is the best oil to use in a blaster?

Bel-Ray or Yama-lube it is my experience that Bel-Ray gives very good protection and Yamaha has spent the time developing the oil specifically for the two-stroke Yamaha's. I have owned both Tecate 4's and TRX250R's and either ran Bel-Ray or the manufacturers oil and rebuilt them once each year atleast a top end rebuild just to be safe and the wear was minimal.