Just wondering if it matters what fuel to put in my mc21?

I normally put in bp ultimate, but just wondering if i should be putting in premium or regular unleaded?

I don't know if it matters or not. I use pretty much any of the 98 RON stuff, excluding Vortex (heard way too many bad stories about carb'd bikes and that stuff).

I had the dyno tuning done for my mc18 on whatever Mobil's 98 RON stuff is ("Synergy" maybe?) and got 61 or so HP out of the bike on a 30degree day, so it can't be too bad.

VB