Nothing in the octane to address or affect tappet clatter. Octane is literally the ability of the gasoline to resist pre-ignition or detonation, also called pinging. Octane is not a measure of the amount of energy stores in the gasoline. Pre-ignition is very dangerous for an internal combustion engine. And the burn cycle starting at the wrong time adversely affect performance. What a higher octane does is it allows you run a different engine tune, one that might allow a more aggressive performance oriented timing. On a stock engine, regular gas should be fine. And switching only the octane of the gasoline will not lead to any more performance.
Having said all that, I have always ran higher octane in my Fury. I did have my ECU reflashed, so I am getting benefits from the higher octane. In addition, I have been running no-ethanol pure gas. I run this in both my bikes. No real gains in mpg or performance per say, but I prefer it for them as they can tend to sit idle longer, specially in Colorado winters.
