Thank you very much kwackboy, if you send me the address I will try to pop in next week.
Just for the peace of mind, I don't want the Suzuki service charge me for something is doesn't need changing....
Infield: the engine was fairly warmed up (after 8-9 miles riding), clutch out (in natural)
Bake might had a good point about the hot weather, today the sound was barely noticeable.