Add a Tachometer

[wacio]

Originally Posted by 5th_bike

The voltage drop is simply from the wire resistance, your headlight draws several amperes so part of the battery voltage gets lost as heat in the wiring. To get a better reading, connect the wires closer to the battery, or on a circuit that doesn't draw much current. At the horn, the voltage only drops a bit when you honk. The yellow wire at the horn is 12V, I connected the +12V (red) wire of my tach there.

Not connecting it to headlight bulb wiring. I'm using brown wire that was some option in harness - also in the headlight enclosure. From schematic it does not seem to be connected to anything else...

BTW: Checked voltage at the horn - its 11V. Maybe my ground somewhere is weak