I got the same growling at take off sometimes on my -09 500 r. also have a wisseling sounds when driving at 70 kmh and its very anoying. had it at the workshop and they rugged up the edges in the clutch, ( the sounds comes from that the gripping part of the clutch gets worn, like shined when its supposed to be a rugged surface. anyway two weeks after its been in the workshop the growling is back so i just think that the clutch is of a bad quality.
So i heard of a brand called malossi a scooter sparepart brand for tuning and found this, maybe its time for a change?? check the link!!!!
http://www.malossistore.be/Prodotto.aspx?type=M&MM=MO/KYXC500&C=5213333I think this cluth might get our scooter a quicker take off too.. =)