I'd check for vacuum leaks around the intake manifold, ducting between the intake manifold and the maf, and the vacuum hoses under the acoustic cover. Use a can of carby cleaner with a nozzle so that you can focus the spray. Preferrably do this on a cool engine, start the motor and let the idle settle, then systematically spray the carby cleaner around the intake duct and manifold and listen for the idle to drop and recover.
Good luck and let us know how you go.
Riding in style