i dont run synthetic and a straight 30w you dont need synthetic its only lubingthe crank and gears IMO non synthetic is fine for a 2stroke but 4 stroke a must..
If you run the CORRECT oil and GOOD oil you don't have to change it every week! and the clutch runs in that oil too! it needs the CORRECT! oil or you'll burn it up!
This IS the sh*t!!!!!! Red Line Oil: Gear Lubricants