Wrapped the rogot in paper and tape to prevent metal shavings from the file process to stick to the magnets, getting metal dust off the very.. and i mean VERY strong magnets is no fun...
no more jagged surface !! 8)
Then i removed both bearings and checked them for smoothness, the pulley side bearing had a very small amount of roughness to it, barely noticable really.
I used a light oil and applied it to the edges of the sealed bearings, spun them up and work the oil in, flipped them around and put the motor back together, powered it up and zoom zoom.. nice and smooth once again. 8)
Re-installed the chain, and went for a short test ride, so far so good !!