Thank you to all who 'chimed' in on this.  My first expedition into a typewriter and I'm in awe of the design, engineering and precision of the mechanisms; the only thing close might be watch repair. There sure are tiny screws and springs buried in there.  Certainly makes my ham fisted motorcycle repair work seem simpleminded by comparison.
     I did get the bell out, polished to a mirror shine and reinstalled without damaging anything else and without losing any parts along the way. Minor improvement, but the 'clunk' is louder than the bell.  Clapper is correctly positioned, best I can tell.
     I did wonder about a spacer under the bell but didn't try and doubt I have a washer small enough.  Regardless, I'll let this ride for a while.  
    You all have helped a lot with ideas that inspired enough confidence to get into this sweet machine a bit.  Thanks!