I dropped wossner in to my -11's throat. 2 earlier were original S3 and lasted 40hours and 60 hours. After that so loud piston slap both times thay I thought my bearings have failed... Hope to that wossner lasts longer. I've allways used good premix oil, clean airfilter, proper jetting etc...
Must be something wrong in those oem pistons... my bike has now 125 hours in it and there shouldn't be need for piston change at these hours...