I ran my first track day at Shannonville on a Yamaha FZ6R (not as much power as your Monster) with Bridgestone BT-021's with about 2000 km on them. I ran in the green group with 15 minute sessions, and I melted the tires. After about 6 laps each session in the afternoon, I could feel them getting really greasy. Even the starter (from Riders Choice) commented that I'd better replace them, just by looking at them before I went out. I put Pirelli Diablo Rosso II's on before the next track day and it was an unbelievable difference. I would say, be prepared for them to get greasy later in the day. They really can't handle the heat they'll generate on the track.