TOPIC:

I'm starting the process of tearing apart my gauges and controls to get them looking more like a cafe rat and I've found just about everything I need thanks to a number of threads here. The one thing I'm missing is a good solution for a tach.

I've found a number of electronic tachs that match the speedo I already purchased but they're all described as being for use with a twin with dual fire ignition. From what I know of tach signals I think this will work with my quad but I would feel better with the blessing of those who know better than I.

My KZ550-F1 is already running a stock electronic tach so the plan is to just hook into the factory wiring.

I THINK dual fire means two plugs per cylinder. I think one coil fires both plugs to get better combustion. I think I should probably not comment on Harley lingo as I have never owned a Harley although in my advanced middle-age crisis mode, I keep getting drawn to fake tatoos and Motor Company orange and black colors... I have a buddy who wrote a VERY (as in anal) description of how to install an electronic tach on a Vulcan you might find of interest. The wiring part required a resistor I believe:
home.comcast.net/~manjo1111/BUBF/TACH_Install.htm

The tach signal on the 550's comes from one coil. Each coil behaves exactly like a dual-fire coil on a parallel twin.

The nomenclature is somewhat ambiguous, though. By "dual-fire", I mean a coil which fires two different cylinders. Some manufacturers call it a "dual-fire" system if there are two coils each firing a single cylinder. Other manufacturers call it "dual-fire" if one coil fires two cylinders. That's some craziness in the Harley world.

If an aftermarket tach works on a 360-degree parallel twin with a single coil (like the KZ400 and KZ750 twin), then it should work on the 550 four. But if it doesn't, it's not difficult to make an adapter to combine coil signals. I use a car tach on one of my 550's which required a little adapter.