The sound of a thousand people screaming and running for the door. Any mineral based 10w40 is fine for the first 10k miles. Then use either the same, mineral based, or go onto synthetic......whichever your wallet prefers.
My local shell dealer was horrified when I opted for 'Helix super' instead of the 'Extra special Super-dooper,synthetic,only for motorcycles' oil....then again,he's a shop assistant and I'm an engineer,and I save a wad of cash using the 'proper' mineral oil!