I recently purchased a new 3" Betson/Imperial trackball.  The problem is it has very little roll time.  With a strong stroke, it only gets about one second of roll.
The first thing I tried was to break the bearings in with a drill.  I drove them for ten seconds in each direction and it made no difference.  
Today, I put two drops of 3in1 on each bearing.  I was sure this would do it but, to my surprise, there is no improvement.
Are trackballs supposed to roll a lot?
One ting I do notice is that the structure where the rollers are held, press the bearings against the rollers putting some extra friction there.
Any input will be appreciated.