Bills & parts is true, talking is a ? and was the chain guides also replaced.
so only 2,600 Km is about 2 months riding, are bills DATED 2 months ago. check oil colour and smell it.......burnt or not, clutch plates smell are things to look at and clutch free travel if large is Ok if very short means need replacement. gaskets, new: springs, frictions and steels plates. isn't a hard job to do just pay attention to details like what way were the steels punched out and remove any burr's off them cogg's an look at the basket of mating to steel cogg's, you can add stiffer springs (slighty more) to have less slippage.