How to Connect a Universal Motorcycle Tachometer

The aftermarket motorcycle equipment industry offers several different handlebar-mounted universal tachometers that can be installed in virtually every motorcycle. These tachometers use one of two methods to transfer rotation of the engine to the tachometer's indicator needle: a cable driven off of the engine's crank or camshafts, or an inductive pick-up that detects electrical pulses from the spark plug cables. Cable-driven tachometers are intended as direct replacements for factory-equipped tachometers. However, an inductive-type tachometer can be equipped on a motorcycle that was not fitted with a tachometer from the factory.

Things You'll Need

• Socket wrench and sockets
• Allen wrench set
• Combination wrench
• Phillips-head screwdriver
• Pliers
• Multimeter
• Electrical wire taps
• Black electrical tape

Instructions

Cable-Driven Tachometer Installation

1. Remove any body or fairing panels to provide access to the engine as needed, using a socket or Allen wrench.

2. Unscrew the tachometer drive nut from the engine, located either on the crankcase of cylinder, using a combination wrench. Push a new tachometer cable into the engine, then screw the tachometer drive nut into place over the cable.

3. Mount the universal tachometer onto the motorcycle's handlebar or the upper fork clamp using the bracket included with the tachometer. Tighten the tachometer bracket bolts using a socket wrench.

4. Screw the upper end of the tachometer cable onto the threaded post on the rear of the tachometer. Screw the tachometer cable nut into place using pliers.

5. Route the pair of wires on the back of the tachometer to the opening at the back of the headlight.

6. Remove the headlight outer trim ring using a Phillips-head screwdriver. Pull the outer ring and the headlight bulb out of the headlight. Unplug the headlight socket. Splice the tachometer's red, positive wire into the headlight socket's low-beam wire.

7. Turn the ignition on but do not start the engine. Flip the headlight dimmer switch into the low-beam position. Turn on a multimeter and set it to read a 12-volt DC scale, using the meter's settings knob. Place the meter's black probe in the headlight socket terminal connected to the black wire. Place the red probe into the remaining pair of wires, one at a time. The wire that indicates a 12-volt reading is the low-beam power wire. Turn off the ignition and remove the multimeter probes.

8. Splice the tachometer's red, positive wire into the headlight socket's low-beam wire and the black, negative wire into the socket's black wire using electrical wire tape. Turn on the ignition switch to verify the tachometer illuminates. Check that the tachometer is spliced into the right headlight wires if the tachometer does not illuminate.

9. Reconnect the headlight bulb to the headlight socket. Push the bulb and the outer trim ring into the headlight, then screw the trim ring screws into place. Reinstall the fairing or body panels removed earlier.

10. Start the engine and observe the tachometer. If the tachometer display does not indicate the engine's rpm, make sure the tachometer cable's square drive tips are seated in the tachometer and the engine. Stop the engine if the tachometer is operating correctly.

Inductive Pick-up Tachometer Installation

1. Remove the seat and any body or fairing panels to provide access to the motorcycle's spark plug cables as needed, using a socket or Allen wrench.

2. Mount the universal tachometer onto the motorcycle's handlebar or the upper fork clamp using the bracket included with the tachometer. Tighten the tachometer bracket bolts using a socket wrench.

3. Route the black and red wires on the back of the tachometer to the opening at the back of the headlight. Route the remaining wire, the inductive pick-up wire, to one of the spark plug cables.

4. Wrap the inductive pick-up wire five complete times around the spark plug cable, then wrap both wires with a single coil of black electrical tape.

5. Remove the headlight outer trim ring using a Phillips-head screwdriver. Pull the outer ring and the headlight bulb out of the headlight. Unplug the headlight socket. Splice the tachometer's red, positive wire into the headlight socket's low-beam wire.

6. Turn the ignition on but do not start the engine. Flip the headlight dimmer switch into the low-beam position. Turn on a multimeter and set it to read a 12-volt DC scale, using the meter's settings knob. Place the meter's black probe in the headlight socket terminal connected to the black wire. Place the red probe into the remaining pair of wires, one at a time. The wire that indicates a 12-volt reading is the low-beam power wire. Turn off the ignition and remove the multimeter probes.

7. Splice the tachometer's red, positive wire into the headlight socket's low-beam wire and the black, negative wire into the socket's black wire using electrical wire tape. Turn on the ignition switch to verify the tachometer illuminates. Check that the tachometer is spliced into the right headlight wires if the tachometer does not illuminate.

8. Reconnect the headlight bulb to the headlight socket. Push the bulb and the outer trim ring into the headlight, then screw the trim ring screws into place. Reinstall the fairing or body panels removed earlier.

9. Start the engine and observe the tachometer. If the tachometer display does not indicate the engine's rpm, make sure the pick-up coil is wrapped tightly around the spark plug cable. Stop the engine if the tachometer is operating correctly.

References

• Trailtech Vapor Installation Instructions; Trail Tech Incorporated
• Acewell ACE-3200/32XX-AX Series ATV Computer User's Manual; Acewell Meter