Most bikers probably have been in a situation when the motorcycle just refuses to start and it might be down to some sort of electrical problem. Here we highlight the most common issues, how to detect and resolve them.
Fitting a voltage meter (with a switch, so it doesn't constantly drain the battery) helps detecting many electrical problems, including:
This is the most common problem as motorbike batteries are small due to space constraints and some manufacturers are also trying to reduce the overall weight of the motorcycle
You can hear the starter motor cranking, but it does not have enough power to start the engine. The sound gets weaker as the leftover juice from the battery gets drained and you hear the starter give up sooner and sooner at each attempt. When the battery is completely drained it won't make a sound.
The starter motor keeps cranking constantly and powerfully (you cannot hear it dying off) as you are attempting to start the vehicle is a sign of a charged battery
Most car and motorcycle batteries are 12 volt, they just differ in capacity, so it can take 2-3 days to fully charge a car battery with a motorbike battery charger. For example it took 60 hours to fully charge a 48 Ah car battery deflated to 6.4 volts with an Optimate 3 motorcycle battery charger.
The alternator generates electricity and recharges the battery while the engine is running
The bike shows symptoms of a flat battery after longer journeys (10 miles+) or even dies off while riding. Check the voltage at the battery with a multimeter, it should increase while revving the engine.
After jumpstarting the motorcycle runs fine means it is supplying the ignition system with enough power. Attach a multimeter to the poles of the battery to check the voltage (should be between 12-12.6 volts with ignition off), then start the engine (should go up to around 13 volts) and rev it (now it should peak to over 14 volts).
Starting the motorcycle blows the fuse immediately killing the electrical system to prevent further damage
The motorcycle starts fine in neutral, but when first gear is engaged the engine stalls immediately
If the motorcycle fails in start in neutral or still runs after a gear is engaged
The motorcycle does not start at all or only when the clutch is pull/released at a certain position
Unplug the connector under the clutch and create a direct electrical connection between the two contact points the try starting the vehicle
Intermittent starting problems or clicking sounds from the starter after the engine started
Electrical testing of the starter relay with a multimeter is required