I fully understand you Don;D
I have NOS speedometer and tachometer for my K6 in their boxes. Too good to be used.
The original speedo is still working and has all history. It reset itself 10 years ago.
Important to store with face up so it will not leak needle damper fluid inside.
But, if your bike does not have any alternative, use them.
Or use a later setup, K3-K6. Often found on eBay, MPH versions