Let’s get positive

Troubleshoot your reg-rec issues and never go flat again

All bright on the night?

If the engine turns over slowly when you press the starter it’s often an early sign that the battery isn’t fully charged and in a bike that’s used regularly, this can indicate a problem with charging. Also, when the bike is running, headlamps that dim when the indicators or brake light are used are another sign something’s not quite right with the charging system.

Meet the multimeter

Next, you’ll need to equip yourself with an electrical multimeter. These hand-held testers are inexpensive and easy to use and allow you to measure various electrical values, such as resistance and voltage, across differing ranges. For a simple bike battery voltage test, turn the dial to the V (voltage) section, and the pointer should be set to the 20v range.

Rectify the problem

Most charging issues stem from a fault with the regulator-rectifier – the component that takes AC current from the alternator and changes it to DC and regulates the voltage to suit the battery’s requirements. Usually it’s a relatively straightforward fix. First of all you need to work out whether it’s the reg-rec or the battery that is at fault.

Assault on battery?

With the multimeter set to the 20v range, check the condition of the battery with the bike’s ignition turned off. A healthy battery should give a reading of at least 12.6v. If it reads less, place it on charge for a couple of hours, then leave for half an hour before rechecking the voltage. If the voltage has dropped to less than 12.6v replace the battery.