What to Do When Your Motorcycle Won’t Start: Tips & Fixes

WHAT TO CHECK WHEN A MOTORCYCLE WON’T START

SCENARIO 1: A SILENT STARTER

If you press the start button and nothing happens, but lights and instruments are active (indicating you have battery power), follow these steps to try and diagnose the issue:

• Check that the OFF/RUN switch is in the RUN position. Even if you never use this switch, it may have been set or moved to OFF accidentally.

• To engage the starter, many motorcycles require the clutch lever to be squeezed against the handlebar or that the transmission is in Neutral, and some motorcycles require both of these steps. This is to prevent the motorcycle from starting in gear. When the clutch lever is pulled tight against the handlebar, it will engage a small switch. Sometimes this switch can become stuck, and you can reset it simply by squeezing and releasing the clutch lever a few times. Some motorcycles will start without pulling the clutch lever if the transmission is in Neutral – this is a way to bypass the clutch switch.

• Some motorcycles also have a safety switch on the side stand. The stand must be retracted (up) for the motorcycle to start. Because it is under the motorcycle, this little switch can get dirty and stick accidentally. You can easily clean it with soapy water and a toothbrush or rag.
  
  

SCENARIO 2: YOUR MOTORCYCLE HAS NO JUICE

When you try and start your motorcycle, if the instrument display but lights do not activate when the ignition key or switch is turned on, there is no power from the battery reaching the motorcycle electrical system. Start by checking:

• That the battery terminal leads are tight and free of corrosion.

• Most motorcycles have a main fuse between the battery and the wiring harness. This is usually a large two-prong fuse. If the fuse is blown, no power can flow from the battery. Some motorcycles may carry a spare fuse or two near this main fuse holder. Try replacing the blown fuse. If the fuse blows again, there is likely a short somewhere in the electrical system, and you should take the motorcycle in for further service.

• The battery could be completely discharged. Use a voltmeter to check the voltage across the positive and negative terminals.
  
  

Learn more about how to charge a motorcycle battery.

If the motorcycle quits running while you’re riding, won’t restart and the battery seems weak or dead, the problem could be that the charging system has failed. As you are riding, the motorcycle lights and fuel pump have most likely drained the battery to the point where the motorcycle can’t function. Either charge or change the battery, and with your voltmeter check the voltage across the positive and negative terminals with the engine running and throttle advanced above idle. The meter should indicate 14.0 to 14.7 volts. If you only see about 12 volts, no charge is going into the battery, and you should have a service technician check the system.

SCENARIO 3: YOUR MOTORCYCLE HAS SOME JUICE

It takes full battery power to turn over the starter. If you push the start button and hear a click, or a series of clicks and the starter does not engage, your battery may be weak but not dead. There may be enough power to activate the lights and instruments. This situation is often caused by accidentally leaving the parking lights on or by leaving a powered accessory like a portable GPS or audio system turned on when the motorcycle is parked. If you are riding with several accessories, especially with heated gear, you may be drawing more power from the battery than the motorcycle charging system can replace. Eventually the battery will be drained to the point that the motorcycle can’t function. To trouble-shoot this situation:

• Check that the battery terminal leads are tight and free of corrosion.

• If there’s an obvious issue – you left the parking lights or an accessory on, for example – turn those items off and simply charge the battery using a battery charger.

SCENARIO 4: THE ENGINE CRANKS BUT THE MOTORCYCLE WILL NOT START

If the starter engages and cranks the engine, but if just won’t fire, try these trouble-shooting tips:

• Check that the battery terminal leads are tight and free of corrosion. Late-model motorcycles require specific voltage to function.

• If your motorcyle is equipped with a fuel petcock – the valve that controls flow of fuel from the tank – make sure it is in its “ON” or “Prime” position. On older motorcycles the petcock is manual. Other motorcycles may have a vacuum control to turn the petcock on and off automatically. This vacuum line could become disconnected or leak, which would keep the petcock from opening. In this case simply replace the line.

• It sounds obvious, but make sure there’s fuel in the fuel tank. If the fuel level is very low, you may need to switch the fuel petcock to its “Reserve” position to restore fuel flow and then find some gas.

• The fuel filter may be clogged. Try replacing the filter (see your operators manual). Motorcycles with a petcock also have a filter that is within the fuel tank, which could become clogged with dirt or fine rust particles. You’ll need to remove the petcock to check this filter. Sometimes the filter can be temporarily cleared by rocking the motorcycle back and forth to swish fuel around this filter.

• If the motorcycle has been in storage or simply parked for more than a few weeks, oxidized fuel may have clogged small passages in the carburetors, in which case the carbs will need to be removed and professionally cleaned. Modern gasoline, especially fuel containing ethanol, can begin to break down in as little as 30 days. If your motorcycle is going to be parked for more than a few weeks, it’s essential to use a fuel stabilizer additive. After adding the additive to a tank of fuel, ride the motorcycle a short distance to get the treated fuel circulating in the entire fuel system.

• Spark plugs may be fouled or the spark plug wires may be loose or in bad condition and shorting. Try installing new plugs, and make sure the plug lead caps are tight and in place. If the spark plug wires appear dried out or cracked, they may not be conducting properly and should be replaced. Also check that the leads from the coil are in good condition. Learn more about motorcycle spark plug FAQs.

• If your motorcycle has an electric fuel pump and you don’t hear it humming when you turn on the key, the pump may have failed, blown a fuse, or a wiring connection to the pump has come loose. If a fuse and the wiring connections look OK, you’ll likely need to have the fuel pump replaced, a repair best handled by a professional service tech.

• Check that the exhaust is clear. If the engine can’t pump air through the exhaust, it can’t start. This is a common problem if the motorcycle has been in long-term storage and mice have built a nest in the exhaust. If you suspect a rodent infestation, you’ll probably have to remove the muffler to clear the nest.
  
  

If needed, see your local authorized Harley-Davidson® dealer to schedule regular service per the schedule outlined in your operator's manual. It’s the best way to ensure reliable performance season after season.