Instruments

The instruments are the panel in front of the handlebar: speedometer, odometer, often a fuel gauge, rev counter and warning lamps for neutral, high beam, indicators, oil and the engine (MIL). Older bikes use a mechanical speedometer driven by a cable; newer ones use an electronic unit fed by a speed sensor.

What it does

The instruments tell you speed, distance, fuel and faults. Electronic clusters need a steady 12 V supply, an earth and signals from sensors and switches. Water getting in, vibration, a weak battery or a poor plug make them reset, flicker or go dark. Mechanical speedometers fail when the cable or drive gear wears.

Signs it is worn or failing

• Instruments or dashboard are dead.
• Speedometer or odometer does not work.
• Warning lights flicker or come on wrongly.
• Fuel gauge reads wrong.
• Fogged glass or water inside.

When to replace it

When it has power and earth at its plug and the sensor signals are good, but still does not work; or the case is broken and lets water in. Some parts (bulbs, glass) can be replaced alone.

What to match when buying

• Match make, model and year, plug and wiring. Speedometers are calibrated for wheel size and sensor; a wrong one reads wrong.
• In many countries changing the odometer reading is illegal. Keep a record of the old reading when fitting a new unit.
• Mechanical clusters: match the cable fitting.

Fitting notes

• Home job: Check power to the instruments, then Check the speed sensor or Replace the speedometer cable.
• Key off before unplugging. Fit the rubber mounts so vibration does not reach the unit.

Reference (K-Light 125)