It's a 2004 749S thing. They're very sensitive to cam timing settings and need to be set up correctly. From the factory it'll probably be incorrect as Ducati released updated settings after the bikes were produced. You need to go to a Ducati dealer and get a full setup - cam timing, CO2 and idle. A Ducati delaer would have done this as part of the PDI but I doubt the Yamaha dealer would have.
I know this becuase I have an '04 749S too
