How to Wire a Sportster Tachometer

by Tom Becker

The Harley-Davidson Sportster line of motorcycles is designed with all the performance and convenience of modern motorcycles combined with the classic design of vintage Harleys. They don't always come exactly like you want them right out-of-the-box, so knowing how to add custom accessories, such as gauges, is necessary for customizing your Sportster. Harley-Davidson manufactures a tachometer kit that can be used to add a tachometer gauge alongside the factory-installed speedometer for a custom gauge setup.

Step 1

Remove the two bolts at the top of the speedometer with a 1/4-inch hex wrench then remove the speedometer. Unscrew the two bolts securing the handlebar clamp in place with the 1/4-inch hex wrench. This clamp is in the center of the handlebar. Set these two bolts aside for later use.

Step 2

Unscrew the upper fork bracket cover with the 1/4-inch hex wrench. The upper fork bracket cover is located beneath the handlebar where the front forks attach to it.

Step 3

Remove the four Torx screws on the sides of the rear riser cover with a T-25 Torx driver. The rear riser cover is just beneath the location of the handlebar clamp.

Step 4

Pry out the tabs on either side of the electrical harness panel with a standard jeweler's screwdriver. Pull the electrical harness out of the riser to expose the Deutsch connector. This is the connector that controls the electrical wiring of the components in the handlebar. Disconnect the Deutsch connector.

Step 5

Use the jeweler's screwdriver to pry the secondary lock out of the Deutsch connector. The lock is made of orange plastic and has four square holes and 12 small circular holes. This will expose the ends of the wires of the handlebar components.

Step 6

Remove the following wires: Orange/White (slot 1), White/Green (slot 2), Brown/Purple (slot 11) and Black (slot 12). Do not remove any of the other wires. Remove these wires one at a time by prying up the locking tab holding each one of them in place with the jeweler's screwdriver then sliding the wire out.

Step 7

Cut the black wire leading from the Deutsch connector to the speedometer with a pair of needle-nose pliers.

Step 8

Unscrew the speedometer reset switch boot counterclockwise until it comes loose.

Step 9

Remove the two screws securing the back plate onto the speedometer with a 3/32-inch hex wrench. Remove the back plate and wiring harness from the back of the speedometer. Remove the speedometer gasket from the base of the speedometer. Pull the speedometer out of its bracket, leaving the upper gasket in place.

Step 10

Place the speedometer in the dual bracket included with the Sportster tachometer kit. Reconnect the speedometer's wire harness to the Deutsch connector.

Step 11

Assemble the wiring harness for the tachometer by placing the orange wire into the far left hole, the black wire into the next hole to the right (after the large plastic divider) and the pink hole into the next hole to the right. Cut off the opposite end of the orange wire with the needle-nose pliers.

Step 12

Snap the completed wiring harness into the back of the tachometer. Slide the tachometer into the empty side of the dual bracket, next to the speedometer.

Step 13

Locate the black wire that you cut earlier which ran from the speedometer to the Deutsch connector and strip the insulation from its end with wire strippers. Strip the ends of the black wires from the tachometer and speedometer and twist them together. Crimp the two wires together using the connector supplied with the tachometer kit with a crimping tool. Do the same with the orange wires.

Step 14

Insert all the wires into the Deutsch connector in their correct slots then replace the orange secondary lock.

Step 15

Remount the electrical wiring harness panel by prying its securing tabs with the jeweler's screwdriver and snapping it into place. Replace the handlebar clamp and secure it in place with its two bolts but do not tighten them. Replace the front riser cover with its four T-25 Torx screws. Replace the upper fork bracket cover with the 1/4-inch hex wrench.

Step 16

Install the new dual speedometer/tachometer bracket into place on the handlebar clamp and bolt it in with the 1/4-inch hex wrench. Tighten the handlebar clamp bolts with the 1/4-inch hex wrench.

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