My Motorbike Won’t Start: What Should I Check?


Author:
Last Updated: 10th March 2021

We’ve all been there. You go to bed thinking everything is OK with the world then wake up the next morning and your motorcycle won’t start.

We’ve made a list of a couple of things you should check before you give in to despair.

If you’ve already diagnosed the problem you might want to try jump-starting your motorcycle, a portable jump starter will come in handy for this.

 

Starting vs Turning Over

A mechanic will typically describe your bike’s issue as “not cranking/turning over” or “not starting”.

This is important – if the starter motor sounds like it’s turning over, as usual, your issue is probably the battery.

If the engine cranks but doesn’t start, it could be having trouble producing a spark, getting fuel, or creating compression.

 

First Step – Check the Obvious Stuff

Without wanting to patronise, the simple things should be checked first. Even the most experienced rider can have a brain freeze and miss the obvious…

  • Check the killswitch
  • Petrol tank – is there any fuel in the tank, is there a fuel valve that needs opening?
  • Neutral gear and clutch – many bikes won’t start unless they are in neutral and the clutch is held in
  • Kickstand – is the kickstand safely stowed?
  • Any obvious loose or frayed wires?

 

Second Step – Battery Diagnosis

Visually inspect the battery first. Bulges, cracks, leaks, discolouration, or a broken terminal can all be diagnosed by looking. If it looks good, then it’s time to check the battery in more depth.

If you don’t have any tools to hand, the easiest (but not the most accurate) way to see if your battery is OK is to either turn on your lights or sound the horn. Some bikes won’t let you use the lights until the engine is running but the horn should work. If it sounds weak or changes tone or pitch, it’s usually a sign that the battery is dying.

The best way to accurately test your battery is to use a multimeter. This is a useful tool around the house too. A decent, generic one can be had cheaply on Amazon.

  1. Access the battery. Depending on your bike, this may involve removing faring or the seat. Some people use battery pigtails to make charging and testing easier. These are just extensions that you can attach to the battery terminals to allow easier access for charging and testing.
  2. Set the multimeter to 20V DC (some advanced ones auto-detect), put the red diode on the positive terminal then the black diode on the negative.
  3. Check the reading on your screen. Anything over 12.4 should get you started.
  4. If the reading is any lower than this, you won’t be going anywhere without a charge.
  5. If after a full charge, your bike doesn’t read the full 12.6V – you may need to replace the battery.

Note: Make sure you test your battery after the bike has been sitting. Otherwise, you won’t get an accurate reading.

Check out this article on the best motorcycle battery chargers.

 

Motorcycle wont start but battery is good?

If you’ve ruled out the battery move onto these troubleshooting steps.


 

Third Step – Spark Plug Check

dirty spark plug

  1. The engine should cool before you start this process. Put your bike on its side stand and remove whatever is necessary to access the cylinder head and spark plug (seat, fairing etc,).
  2. Carefully pull the spark plug cable out and put it to one side. Using a spark plug socket and socket wrench remove the spark plug
  3. Check the ceramic part of the plug for cracks or deformity. You’re also looking for blackened or melted electrodes and cracks in the insulation close to where the electrode protrudes. If you have a new plug handy, compare it to the condition of the one currently installed.
  4. If you can see any obvious damage to the insulation or the tip, replace it with a new one.
  5. If there’s no obvious problem, pay attention to the colour of the insulation near the tip of the plug. Ideally, this will be a very light brown colour. If your plug is white and blistered, it indicates that something is making the plug run too hot. If it’s dark brown and wet, it indicates that the fuel system is running rich. Even if this plug is damaged, keep it so you can show it to your mechanic later.
  6. If the colour is good, it’s time to check the space in the plug. Using a feeler gauge, check that the gap between the electrodes at the spark plug’s tip. The correct gap will be indicated in the owner’s manual of your bike or easily found online. When using the correct leaf on the feeler gauge, you should feel a slight pull as you place the tool into the gap.
  7. If the leaf of the tool cannot be pulled through or pulls through without any resistance, adjust the gap with needle-nose pliers until you feel a gentle pull as you draw the tool through the gap.
  8. Put the plug back into its insulated cable cap. Holding it by this cable, touch the electrodes lightly against the engine cylinder head. Watch the space between the electrodes as you start the engine. You should see a spark between the electrodes and cylinder head at this point. If you’re not getting any spark, it might be the ignition coil that’s your problem.

Fourth Step – Fuel Valve

The fuel valve, or petcock valve, on older motorcycles, has an on, off, and reserve setting.

There were a few reasons for this, the most important being that gravity could continue to feed fuel to the carburettor (the tank is higher than the carb), eventually flooding and causing problems.

When leaving bikes like these sitting, the valve needs to be put in the “off” setting for safety. Check this if you’re on an older bike. It’s usually under the tank on the left side.

Fuel injection systems have made this obsolete, so your bike may not have one.

 

Fifth Step – Blown Fuse

Check the main fuse on the motorbike, if it is blown, nothing electrical will work.

It’s also possible to have a faulty fuse that works but keeps your bike from running at 100%. This can be the cause of seemingly random cutouts and patchy periods of things not working properly.

Keeping a spare fuse with the bike is not a bad idea, as they are cheap and easy to swap out.

If the fuse keeps blowing, it’s a clear sign that the electrical system is being overtaxed. This might be a result of too many accessories drawing power or some faulty wiring that needs fixing.

 

Sixth Step – Ground Wires

This can yield similar problems to a sketchy fuse, with things working intermittently then failing.

Check your manual to find out where all the ground points are on your bike and check if they’re all connected correctly.

If you’ve recently taken your bike apart, done some custom work, or resprayed the frame, it’s not uncommon for ground points to get messed up. They need to be a clean metal-on-metal connection to work correctly and be safe.

 

Conclusion

Well, we’ve probably missed something. To be fair, the number of problems tends to increase with the age of the bike.

If you’re new to riding, buying a bike that’s both modern and fairly simple will help you learn the basics as you go, and check out this article for some basic motorcycle maintenance pointers.