Worth checking the flywheel nut. I need to do mine too!
Pipe bang from a bit of extra fuel on the pilot. If I coast in gear downhill my bike will knack or ignite unburnt fuel in about every 5-10 seconds. Still not as often as I've seen some other brands of bikes do it either.
Usually becomes more noticable the higher you try and set the idle.
A little reading:
http://www.powercdi.com/manual/combu..._bangs/en.html