Motorcycle Won’t Start But Battery Is Good? (9 Solutions)

It’s easy to blame the battery when your motorcycle doesn’t start—it’s not uncommon for the battery to be the issue.

That said, there are some cases when you know for a fact your battery is good, but your motorcycle still won’t start.

This article lists nine troubleshooting solutions to employ if your motorcycle won’t start, but the battery is still good.

1. Refill Fuel Tank

The first troubleshooting solution for a motorcycle that won’t start even though the battery is still good is ensuring you have fuel in the tank.

In some cases, a faulty fuel gauge leaves riders thinking their tank is full of gasoline when they’re much closer to empty than they think.

Furthermore, if you routinely leave store your motorcycle with a partially full or empty fuel tank, your fuel pump—a critical component of the fuel injection and starting processes—may have incurred damage from drying out.

  • The gasoline in your motorcycle’s fuel tank doubles as the source of the lubrication for your bike’s fuel pump.
  •  Storing your motorcycle with no fuel in the tank causes your fuel pump to dry out due to lack of lubrication, increasing its friction and rate of wear.
  • Lack of fuel lubrication also causes your fuel pump to develop corrosion and rust, triggering starting problems and overheating issues even after you’ve topped off the fuel.

And finally, leaving your motorcycle’s fuel tank empty also lets air in. Air carries moisture which can corrode your tank walls.

When you refill the fuel, the rust flakes off the tank walls and into the fuel pump and the rest of the fuel system, causing starting problems on a motorcycle with a perfect battery.

2. Fix Faulty Electric Starter

a faulty electric starter can cause a motorcycle not to start, even if it has a perfectly good battery.

Loose or corroded electrical connections within the starter cause the most common starter problems.

For example, a problem with the internal windings inside the starter motor or faulty brushes can rob the starter motor of the torque it needs to crank the engine, even if it’s getting plenty of current from the battery.

If you suspect a faulty electric starter is a culprit behind your bike not turning over, inspect its electrical connections and wiring, ensuring the connectors are fastened and rust-free and that none of the starter wirings is frayed, melted, or shorting out.

Like all electronic devices, starter motors wear out from use, eventually. If your starter systems wiring is intact, the engine may be too worn to spin the flywheel and start your motorcycle. If the starter motor is faulty, you’ll have to replace it.

To prevent your motorcycle from developing a faulty starter, store it in a dry, temperate area and inspect your starter wiring per the service intervals suggested in your motorcycle’s owner’s manual.

3. Turn the Kill Switch to Run

Most modern motorcycles equip a safety feature called the kill switch.

The kill switch is typically on the handlebar controls within easy reach of one of your thumbs, making it easy to press if you find yourself in an emergency.

Once pressed to the “Off” position, the kill switch acts as a circuit breaker, killing the engine circuit and instantly shutting off the engine.

One of the most common reasons a motorcycle won’t start even though the battery is still good is because riders use the kill switch to shit off their bike and forget to switch it back to run. If your kill switch is set to off, your engine and circuitry are essentially disconnected.

  • Sometimes, it’s as simple as flipping the kill switch to run and hitting your starter button again.
  • Other times, the kill switch was used to shit the bike off by breaking the circuit, and the rider left the keys in the ignition, killing the perfect battery.
  • And finally, if your motorcycle’s kill switch is corroded, or if the wiring is frayed or shorted out, your motorcycle will develop starting problems regardless of how charged your battery is.
  • A faulty connection can cause the kill switch to break your engine’s circuit even if the switch is set to run.

Make sure to also read our article about why a motorcycle won’t start with the kickstand down

4. Change Bad Spark Plugs

Even if your motorcycle’s battery is brand new and fully charged, worn or damaged spark plugs or faulty spark plug wire connections can make it so your bike won’t start.

Because spark plugs are the source of the spark that initiates the whole ignition cycle, faulty spark plugs quickly result in incomplete fuel combustion.

If the plug is damaged, worn, or corrupted in a way that prevents the spark from jumping across the plug’s gap, the spark plug can’t get into your fuel mixture thoroughly, resulting in unburnt fuel.

Not only does an incomplete combustion cause starting failures, but it can also cause lean air: fuel mix, engine performance loss, misfiring, backfiring, and a noticeable decline in fuel efficiency.

Once you’ve confirmed your spark plug wires are connected properly and are fully functional, inspect your spark plug’s condition. If you’re sure your battery is excellent and faulty spark plugs are why your bike won’t start, replacing your plugs sooner than later is the only solution. 

All spark plugs wear out, eventually; you can extend their life by inspecting and cleaning them per spec and refraining from over-tightening your plugs during installation.

5. Open Your Fuel or Petcock Valve 

Older motorcycles used gravity-fed fuel systems and therefore equipped fuel and petcock valves in their fuel system to aid fuel flow.

Fuel valves are the doorway through which fuel is fed into the carburetor from the fuel tank.

The tank is located above the carb, allowing gravity to run fuel down from the tank, through your lines, and into the fuel valve to enter your carburetor.

The petcock valve is controlled externally, but the rider isolates the fuel tank and seals off the fuel flow during periods of inactivity, preventing potential fuel leaks and stopping your carb’s float valves from sticking.

In some cases, riders close their fuel or petcock valves without realizing it, preventing their motorcycle from starting despite its fully charged battery, in other situations, rust, dirt, or debris clogs or damages fuel valves.

Clogged petcock and fuel valves can cause starting problems on a motorcycle and trigger irreversible damage to your fuel system, engine, and carburetors.

You can prevent this by ensuring your fuel valve is opened adequately, your petcock valves aren’t closed, and by using clean, fresh fuel. And by inspecting, cleaning, and replacing your fuel filter per your manual’s specs.

It might also be that your motorcycle won’t start up because it has run out of gas

6. Clean Out Clogged Fuel Lines

Clogged fuel lines can cause starting problems on a motorcycle, even if its battery is brand new and fully charged.

Whether your motorcycle is carburetted or fuel injected, clogged fuel lines prevent energy from flowing into the combustion chamber to conjoin with the air and form the ideal air: fuel ratio for ignition.

In addition to false starts, clogged fuel lines cause running problems like performance dips, lagging throttle response, misfires, ad backfires.

  • Fuel lines can get pinched from collision damage or clogged from rust, dirt, or debris allowed to enter the fuel tank.
  • If your motorcycle is frequently left sitting without a full gas tank, rust can form on your tank walls.
  • Failure to keep your air filter clean and puncture-free can result in dirt entering your lines.
  • A faulty fuel cap can let dirt and moisture into your fuel supply, corroding or clogging your fuel filter.

You can prevent clogged fuel lines by using a high-quality fuel filter and inspecting and cleaning it per the service intervals outlined in your owner’s manual.

A complete filter will catch any dirt and moisture that may sneak into your tank during refueling before it enters your lines.

We also suggest proper motorcycle storage providers and winterization keep your gas tank clean and free of rust, debris, moisture, and contamination.

If your fuel lines are clogged and preventing your fully charged battery from starting your bike, you can flush your fuel lines following the instructions in the service manual for your make and year model motorcycle.

If the lines are damaged or heavily corrupted, you can replace them to restore your bike’s fuel flow and have it firing up like normal.

7. Replace Leaking Vacuum Lines or Seals

A leaking vacuum line can cause starting problems on a motorcycle, regardless of the battery’s condition.

Vacuum leaks in your bike’s air intake system allow air to enter the wrong places while also depriving the site that needs air from its supply by letting it escape.

Air leaks can manifest as cracks in your intake manifolds or the plastic or rubber components of the intake system.

  • Vacuum leaks are formed by breaks or cracks in seals, gaskets, air intake manifolds, or hoses or tubes that deliver air to the combustion chamber.
  • You can fix a vacuum leak in a motorcycle’s air intake system by replacing the cracked components.

Vacuum leaks are one of the most common reasons a motorcycle with a perfect battery won’t start: air is as essential for combustion as fuel.

Inspect your air intake system regularly for signs of corrosion, wear, cracking, or damage.

Replace any seals, gaskets, hoses, or tubes with bends, punctures, or corrosion on them before they become cracks—be weary of heat damage, as it turns seals and hoses brittle and leads to cracking as well.

8. Replace Malfunctioning Fuel Pump

All fuel pumps wear out, eventually; routine service inspections will catch worn pumps before they develop problems, giving you a window to replace them while the bike starts without issue.

If you fail to catch the wearing pump early on, its performance will dip, and it won’t have the strength to pump fuel in sufficient qualities for starting your motorcycle, even if the battery is sending plenty of currents.

Replace a worn or malfunctioning fuel pump to solve your motorcycle’s starting problems, providing your battery is good.

We also have an article about solutions to a motorcycle that shuts off while riding but starts back up.

9. Clean or Rebuild Your Carburetor

a dirty, corroded, or debris-clogged carburetor prevents fuel and air from entering the chamber for combustion, preventing the motorcycle from starting even if the battery is good.

On older bikes, regularly inspecting and cleaning your car, rebuilding it as needed will prevent starting problems from developing.

Sources

13 Reasons Why Your Motorcycle Won’t Start And How To Fix It | Motorcycle Habit

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