Installed a cheap tachometer on the 1990 Sportster. I’ll upgrade it to something nicer one day, or not. Really only installed it cause the wiring was already there and it was cheap.

The tachometer has 5 wires – 2 for 12V, 2 for ground, and 1 for the engine signal. I tied the two 12V wire together, and the two grounds together (they are separated like this for key position – do you want the face lights in both on key positions – for simplicity yes).

Red and short-black to 12V, green and long-black to ground, yellow with black line to engine signal (the pink wire coming from the coil). Soldered the connections and covered with heat shrink. Installed the pins and connected them to the wiring harness in the headlight.

Mounted it using the mounting bolt for the headlight cover on the front forks. This tucks it in nicely next to the speedo.

Fired it up and it works. Here is a short video of the installed tach doing what an installed tach does.

This tach goes to 13,000 RPMs, the stock one goes to 8k. You are well beyond redline if you get halfway around this dial.

This tachometer is definitely cheap, not sure how accurate it is (or if I care), but it looks kind of cool and was easy to install.

Installation kept me busy for about 90 minutes 🙂 I’ll run it till it breaks, or maybe I’ll find a better one at a swapmeet or something.