It needs to be tightened down hard. If the bolt is damaged then replace it with a decent quality flanged bolt of the same size (M8 x 30mm long, or use an un-flanged bolt with an M8 spacer) and replace the flanged nut with an M8 spacer and an M8 Nyloc nut to prevent it from vibrating loose again. The damage to the mount occurs when the bolt is loose so it needs to be kept tight. If you need an actual torque value, 25ftlb should be enough to hold it all together. There is enough flex in the tubes of the fairing subframe to not need any movement in that mount.