Typically the oil doesn't prevent proper break-in since the oil it has in the first 500 miles is for that purpose. The full synthetic is recommended because of its polymer content, which the transmission requires for adequate lubrication. Most of the metal wear in the first 500 miles is in the tranny, not the motor (remember it's only 8.5 to 1 compression). The motor is usually bedded at the factory, but the transmission needs break-in (which is why it shifts easier and more quietly over time). Going with half-synthetic will not harm the motor, but due to polymer break-down under the shear stress in the transmission, its lubricity will decline more rapidly than full synthetic, therefore requiring an earlier change than the recommended 6000 miles with full synthetic.
Course it's your bike, if you want to risk the trans giving you nightmares that's within your right. 2 pennies now consumed.