Broken odometer on an '81 Seca

Last week I got an '81 750 Seca. Great bike, et cetera, a few problems, one of which is a broken odometer. I've calculated it and it turns over one tenth of a mile every seven miles. I'd like to get it fixed so I can log mileage and fuel economy and so forth.

I've tried disassembling the cluster and got it down to the tach and speedo plates with the gauges in the back. I couldn't get the rest out because the metal pin used to reset the secondary odometer (also broken) keeps it in place. I also don't want to break the circular base for the speedo needle to get the face off. The actual speedometer works perfectly. I would imagine the gears have stripped or something along those lines. Does anyone know how the odometer actually works? Could it be an electrical problem or is it probably just stripped gears? Does anyone know of a way I could get to the gears without forcing or breaking anything? Is there any way that I could fix it or am I pretty much stuck buying a new instrument cluster? Any suggestions would be awesome. I couldn't find any other posts that were specific to the odometers on the Seca, so I apologize for any redundancy.

Thanks.

 

i had mine on a 82 maxim apart once and if i remember correctly the odometer was a gear drive, no electronics and looked like it wasn't meant to
be taken apart
if the speedo works and the odo works a little i'd say some gears are worn and slipping, is there a long worm gear in there ? thats a good place to start

 

Pictures???