pwotoole

I'm assuming that the input to the gas engine tach ckt is from the low side of the ignition coil, which are probably pulses. I have a wiring diagram of the bike's electrical system, and that appears to be the case. Wires are routed from the electronic ignition, and other parts of the electrical system, to a point on the handle bars where a tach can be connected. 3 connections, one is ground, one is 12v, the third comes from a common connection between the ignition case and one side of the ignition coil, which, I'm assuming, comes from the low side of the coil. (or "transformer", mechanics prefer "coil")
Harley didn't put tachs on bikes like mine, keep prices down I guess, but they were kind enough to provide the wiring - in hopes that the bike owner will buy one of Harley's expensive tachs, for well over $100, sometime in the future.

Motorcycle parts are very expensive compared to car parts; they like to put a lot of chrome on them, and stuff. But that doesn't really explain the high prices.
Paddy

Sceadwian

They sell far fewer of them, that explains the high price.

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Sceadwian

One custom fabricated Cmos chip will cost you your next child.
One custom fabricated Cmos chip and 10 million other likes that will only cost you 1.5 times your next child =)
Most good motor heads or serious bike junkies usually have access to a machine shop or friends that do.

It's the mathematics of mass production.

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