As 81 Blackbird mentioned, I had on old post describing the procedure I use for resetting the odometer numbers. But apparently all old posts are gone now.
You can change the odometer numbers to whatever you want. You can reset to 00000.0, or in my case, I was installing a better looking odometer, and wanted to set it to the original mileage that was on my ugly original odometer. Here's the text of my old post about how to do it. I've found that the numbers line up pretty straight when doing it this way:
Take the speedo apart and remove the odometer assembly from the speedo head. How to adjust the numbers may be difficult to explain, but I'll give it a shot. Hold the 5 metal pins on the bottom of the odometer in place as you rotate the 1st wheel on the right(the tenths wheel) forward. When the 2nd wheel turns to the number you want, stop and hold only the left 4 pins. Now rotate those 2 right wheels together, while still holding the 4 pins, until the 3rd wheel turns to the number you want. Now just hold the 3 pins on the bottom, and turn the 3 wheels together to turn the 4th wheel to the number you want. Now hold 2 pins, and turn the 4 wheels together to rotate the 5th wheel to the number you want. Then hold the one pin left and turn the 5 wheels together to rotate the 6th wheel to the number you want. All the metal pins should be lined up on the bottom and you should have the number you want on the top, opposite the pins. It sounds complicated, but once you get started, it's easy and only takes a few minutes.