A. My answer is yes, but don't overdo the amount or use it too frequently to be on the safe side. My recommendation is to use Sea Foam, an effective, but mild additive. I doubt very much that the fuel additive caused your FZ750 engine to blow.
Comment: The answer to this is somewhat controversial in the Virago Tech forum. 9 out of 10 will say yes, and offer personal experience to support their answer.  I have used 'Iso-HEET' by Gold Eagle, to remove water from my gas, and I have used 'Sea Foam' with every tank since both bikes were purchased with no ill effects. Most people report no problems, but a few have said that they have heard of someone who did. My opinion on that is, problems when an additive were used in a Virago are probably just urban legend. 'Sea Foam' and most other additive manufacturers list motorcycles on their containers and/or claim they are safe for all engines.