Because a filter doesn't always clean out the thicker mucousy clumps of oil and they collect on side walls, static parts, things like that.. over the lifespan of the vehicle (this bike has done 72000 km, 20k of them by me over 6 months) but oil changes only take out the free moving oil. that's why you can get oil flushes which are supposed to help dissolve the static clumps.Why would you get gunk in your oil after 1000 miles?
I do know that the oil went from Amber translucent to Dark translucent grey within a week of putting the stuff in
Now when I tap some off to do a check it's opaque black... Time to change.
Attorney rate it definitely did seem to make my bike quieter and it just felt 'happier'.. I can't say I really noticed any performance gains