Looks like you have been here a while , but since this is your first post ... Welcome to the site !!
What i would check is the Chain Tensioner for the cam , i am suspecting its the chain tensioner that came apart , did you hear any loud tapping or slapping like your drive chain might make but coming from the engine ??? , did you notice any hard starting issue ?? , or difficulty or irregular idling ??
It looks like the tensioner exploded (it happens) and the pieces have got ground up by the timing chain , unfortunately with that amount of debris (you did not show the filter) i would be worried about pieces getting into the bearings and causing more issues , if this is the case i would suggest (unfortunately) tearing the engine down and inspecting all the engine side bearings (transmission is completely separate on these engines so i doubt any debris got into it , but it still requires a complete disassembly to get to the crank bearing , if anything (to save you some heartache and teardown) remove the flywheel (make sure you use the correct puller specifically for your bike) and inspect the crank bearing , if you do not see any shavings in the actual bearing and the engine turns over by hand with no binding (remove the plug and turn the engine over by removing the large round plug on the clutch side , and using a socket/ratchet on the balancer shaft , slowly rotate the engine to "feel" for rough spots) , and if it feels free then you might have caught it in time
I would also if all checks out , flush the engine with some clean oil (it does not have to be good oil just cheap "clean" oil and a new filter and check it after a minute of running , this would be after you replace the tensioner (if it is in fact the tensioner) , .......... If , it is not the tensioner , then a complete engine tear down would be necessary to find the failed part which would most likely be a bearing