1981 kz1000...some questions on my bike there

+1
The tachometer that originally came on the bike may have been replaced without replacing the entire cluster.

Patton wrote: Is there a connector between tach and main wiring harness to check for being clean and tight?

The bike at hand originally had a manual tach drive that has been replaced with an electronic tach/voltmeter combo unit.

The original wiring harness would not have a connector for an electronic tach.

Perhaps the combo unit is itself without fault, but wired incorrectly.

The wiring diagram from the KZ750 without the PUSH/VOLTS button could be instructive in this regard.

Good Fortune!

Here's a direct link to the KZ750-N1 wiring diagram in KZr's FILEBASE, which shows wiring for the tach with voltmeter.
www.kzrider.com/filebase/search/finish/1-general/264-z750n1

Note that the diagram shows a switch between tach and voltage.





Good Fortune!