That's how I messed up my CRM. I was racing a guy and had the throttle locked back for a couple of kilometers. When I rolled off it started smoking bad. Still had really good power but I knew what it was like before, more and pretty clean running. Me mechanic chastised my severely.
I still keep the speedo at the top on the NSR but I never leave it wide open for more than a few seconds. I modulate it up an down a bit, not sure if it helps though.