all this crap is comming from somewhere. i'm at half the milage, and have no metal on the magnets whatsoever... not to mention rest of the crap on the screens...
how was your last oil change?
how is your air filter? is the airbox/tb area clean? could something have gotten into the engine through the air intake?
several parts in the engine are made from non-magnetic metals, and i think there is even some plastic in there too (cam-chain runners?)
yes, you could risk it, put new oil in, run engine for a while, then check... but what if it is not slow wear over 100's of kms, but a seriuos failure within last few km's?? by the time you see it, it might be too late.... (been there, done that - it was a plugged oil jet, crank shaft bearing seized, took few mms off the crank )
few things that can be done quite easily without pulling the motor out:
1. check if air box/tbs clean
2. check for oil in coolant
3. compression check - easy to do... not likely this will tell you much, but very low values or large difference between cylinders could shine some light on the problem...
4. pop off the head covers, see if everything there is clean and cams look good...
5. check the clutch... though if all this stuff came from the cluch, you'd likely have noticed it slipping, but again, easy to do, get it out of the way 1st.