Why does my 04' Crf250r take a million kicks to start?

I'm usually able to fire up the bike in ten kicks, but after i've been running it and shut it off, it takes a million to start it again. The plug is new and the fuel is clean high octane stuff and the bike backfires minimal. I realize this is the first year for the honda 250 race bike so it was the first "experimental" bike. Can anyone help me and tell me if re-jetting it or if valves need to be replaced or shimmed? thanks