Install Speedway Instruments microTach tachometer on 2004-later Harley-Davidson Motorcycle

Step 3 Test and clean-up

Step 4: Now is the time to test to make sure everything is working. Turn the key switch to accessory. The tachometer should display a "0" if you connected to the accessory power. If it doesn't light up, check the splice connections using a voltage detector or Digital Volt Meter(DVM). You can open the cover and probe for voltage on the metal part of the splice connector. Make sure there is approximately 12V between the Red and Black wires going to the tachometer. If not double check everything, including wire colors, proper seating of wires in splice connector, everything.

If you have the "0" lit, then go ahead and start the bike. The tachometer should read between 800 or "8" and 1200 or "12" RPM's It is likely going to bounce between 2 or 3 numbers when idling. Rev the engine a bit to make sure everything is working. If there is a problem with the reading check the white wire to make sure it is spliced through well.

Shut the bike off, and button up. If the splice connectors are going to be visible such as behind the headlight or near the neck, then it is best to wrap them up in electrical tape. The self-sealing kind is good. Wrap it nice and tight to keep as much moisture out as possible.

Put everything back together, if necessary use blue threadlock to make sure things stay back together.