What type of oil goes in a yz250?

If your asking about pre-mix oil that you mix with the gasoline, they recommend Yamalube "R" (Yamalube racing 2-cycle oil) Mixing ratio : 30:1 or Castrol A747

For the transmission and gearbox, Yamalube 4 (10W-30) or SAE 10W-30 type SE motor oil.