The idle rpm seems to be a little bit variable and not the same on the side than on the central.;)
It goes down at 1500rpm nd then after 20s 1100rpm, does it seems to be usual ?
else how could I make it normal ?

Ther is a idle adjustment knob on the left side of the bike. about the size of a nickel, right by the carbs, you dont want to go to low and make sure the bike is warm and choke is off. What is the lowest it gets to in neutral, warm, choke off? I beleve normal is around 1000 rpm. hope this helps