If you're changing your oil and filter, don't forget the strainer, opposite side to the oil sight glass, 17mm (?) bolt, side fitting, spring loaded.
These break down over time and disintegrate - my 2001 R1 had 11,000 miles on, serviced it just after purchase.
Check the picture!
Kawasaki part number 16097 1058, around £10.
Wow! >:(
Mine still looks like new.
Thanks for the heads-up.