Here is a tread from the Euro z1000sx Forum:
If the link doesn't work the good bit was:
a) The problem is the tachometer (rev counter) display gets out of sync with the rest of the bike.
b) The bike importer (i.e. Kawasaki UK, or, in my case, Kawasaki Europe directly) are the ones who know of a procedure that has a chance of re-syncing the display tachometer with the bike. This, to me, means that it's obviously not an entirely isolated incident.
c) If the re-syncing procedure does not succeed, you are going to need a new display.
2. When this problem first appeared, I had taken the battery of the bike for winter storage. So I've first tried taking out the battery again and putting it back on. This did not help.
3. Reading on this thread that maybe interrupting it during start up would help it reset, I tried that too. It did not work. Further more, I believe this has a chance for them to later refuse warranty on the clock (unless you're in good relations with your dealer). Since the replacement for the display might be your only chance, you should NOT do this (I was too curious for my own good and tried it anyway).
4. What DID work for me was that old adage - ride it 'till it goes away
I went for a good spin, put it back in the garage (tacho still stuck at 7k). Several hours later I started it again and this time, it got reset to 3.5k. Aha! An improvement!, I said to myself. So I went for another spin and, again, after ending the ride and letting it sit for a bit, when I restarted, it synced back perfectly. SUCCESS!
5. My theory is this: note that in the start-up sequence, the tachometer briefly gets pushed bellow the 7k rpm mark. I believe this is the system trying to collect data on tacho sync and correct it. I'm not sure how it works, but it might be that there was some erroneous entry due to the battery being removed and that the system needed to gather enough data for an average measurement to exclude the aberration registered and reach the correct sync point. So this is where I believe the ride might have helped - maybe it gave sufficient measurements
Anyway, my clocks are back in sync with the bike without needing the bike shipped 400km to the nearest dealer which can execute the importer's sync procedure.