I was running a synthetic blend when I 1st got my Raptor. I changed the oil in my 250 right before the piston/cam install, and I used conventional since I knew I would be changing it again soon. After the piston install (saturday) I would go start it every other day (3 days mon, wed, fri) and let it just warm-up basically, then shut it down. Then I went and rode it for 2.5/3 hours, taking it easy of course. After that I put in full synthetic, now it's time to run it hard. I don't remember how I broke it in when I got it, but the piston looked like $#!t when it was removed.