Motorcycle starting issues can be hard to deduce, even for the most experienced motorcyclist.
While motorcycles are simple machines overall, riders may find that a bike lags at startup due to various issues.
Sometimes it takes some old-fashioned trial-and-error style troubleshooting. Still, if you familiarize yourself with the following list, you can jump right to the most common reasons why a motorcycle takes too long to start.
1. Worn Spark Plug Wire
One of the most common reasons why a motorcycle takes too long to start is because of a worn spark plug wire.
Standard engine vibrations and heat, extreme weather exposure, and improper storage all contribute to the eventual cracks and splits in the spark plug wire that can delay your bike’s starting capabilities. This is why spark plug inspections are a part of routine maintenance.
- We suggest you inspect your spark plug wires while the motorcycle is off, as a cracked or exploded spark plug is dangerous while it’s live, especially while your feet are on the ground.
- Conduct a visual inspection of your spark plug wire, checking for any breaks in its rubber or plastic.
To fix a worn or split spark plug wire, you’ll have to replace it. Again, we suggest routine inspections of the wire. That way, you can return it as soon as it starts to turn brittle from the engine heat before it cracks and causes delayed starts.
2. Restricted Air Intake
If your motorcycle cranks just fine but takes too long to start, stalls after you get it started, or stalls under acceleration, it may be due to a lack of airflow, either because of a clog or a leak in the air intake system.
- A clogged air filter is a motorcycle’s most common cause of restricted airflow.
- Some motorcycle air filters are disposable and need to be inspected and replaced during routine service intervals listed in your owner’s manual.
- Other bikes use reusable metal or mesh air filters. These filters still need to be inspected regularly, but can be cleaned out with a degreaser or soap and water and good scrubbing, depending on the type of filter.
This is one of the most accessible items to fix on the list, so easy that many riders don’t realize how quickly a clogged air filter can cause delayed starts.
That said, if you inspect your air filter and find it isn’t clogged, the airflow may be weakened due to a leak in an intake manifold or somewhere else in your bike’s air intake system.
Air leaks are challenging to diagnose and often require the assistance of a pro mechanic.
3. Improper Engine Timing
If your motorcycle takes too long to start and you hear a ticking sound, and when you do get it started, it backfires and stalls out; it may be due to poorly tuned engine timing.
Furthermore, a bike with I’m[roper engine timing may experience oil leaks and excessive exhaust smoke.
- Engine timing is set differently on modern bikes than on vintage motos.
- Older bikes use a mechanical timing system called a Points System.
- The points on a vintage scoot must be manually set by a pro familiar with your specific make and year model motorcycle.
- If the points are set wrong, your bike will take too long to start and may stall out.
- The tips of these points also wear out over time. Once they do, they need to be replaced, or the timing will slowly delay or advance and cause problems.
- Finally, the engine timing on new motorcycles is governed by its Electric Computer Unit, or ECU.
- The ECU may need to have its programming updated or flashed to restore its timing, or it will continue to start late and stall out while riding.
To fix a poorly tuned engine timing on an older bike, you’ll need to remove the crankcase cover and inspect the timing marks in line. You’ll also have to check your engine valve position, both of which must be set precisely.
We suggest taking a motorcycle with poor engine timing to a pro mechanic, as incorrectly setting the timing can worsen the problem and even lead to total engine failure.
4. Motorcycle Is in Gear
If you parked your motorcycle without taking it out of gear, it might take too long to start until you shift it into neutral due to a safety sensor that prevents a motorcycle from starting in gear and lurching forward with the rider in the seat.
Depending on the make, model, and year motorcycle you’re riding, the bike might crank for a long time but not start, it may make a grinding sound, or it may not even try to start at all if it’s still in gear when you try to fire it up.
If your motorcycle is taking too long to start because it’s still in gear, shift into neutral, and it should start right up with no delay.
For more on this topic, we’ve written an article about reasons a motorcycle won’t start in gear.
5. Is Motorcycle Battery Weak or Expired
The most common reason a motorcycle takes too long to start is due to a battery with a weak charge.
Your bike won’t start if your battery is dead or drained. If your motorcycle’s battery charge is low, but there’s a little juice left, your lights will turn on, your fuel injector will prime, and your bike will try to start over and over.
- The primary cause of a partially charged motorcycle battery is improper storage.
- Bike batteries are charged by a system of components that convert engine power into battery voltage; if the bike sits for an extended period without use, its battery is never recharged.
- Furthermore, your bike’s delayed start may be caused by parasitic battery drain—when the bike’s ECU and electronic features slowly leach power while the bike sits to prevent electrical damage.
If you suspect a poorly charged battery is the culprit behind your motorcycle’s slow startup, test it with a multimeter set to DC Voltage, following the instructions on the specific multimeter you’re using.
Your motorcycle battery needs a minimum of 12 volts to start; if it’s less than that but close, you may need to recharge it to eliminate the long startup time.
That said, if the motorcycle battery reads less than 9 volts, you may need to replace it or at least get it tested to see if its charging capacity is still intact.
If you need to let your motorcycle sit for a while without riding it, hook the battery up to a battery tender so it doesn’t take too long to start the next time you decide to ride.
If you’re sure the battery is healthy, read about reasons a motorcycle won’t start, but the battery is good.
6. Clogged or Faulty Carburetor
One of the most common reasons an older, carburetted motorcycle takes too long to start is because its carburetor is either faulty or clogged with grime, rust, or contaminated fuel.
- Carbon deposits and dirt tend to build up in your fuel system over time. Eventually, these deposits accumulate enough to clog your carburetor’s fuel pathways, particularly the carb jets, which have a tiny opening.
- Air can fill the extra space if you store your motorcycle with a less-than-full fuel tank. Air carries moisture in with it, which can cause rust in the tank that flakes off and enters your fuel supply.
- Finally, a damaged or missing fuel filter allows excessive fuel deposits to enter the carb, whereas a functional filter will remove them from your fuel supply.
When you try to start a motorcycle with a clogged carb, the bike will take a long time to turn over and may stall out as soon as it does or when you hit the throttle. If you suspect a clogged carb caused your motorcycle’s delayed startup, detach the air intake and remove your carb for a deep clean and rebuild.
- We suggest you pay attention to the order in which you dissembled the carb parts for cleaning, as you’ll have to rebuild your carb in the reverse order.
- Some capable home mechanics we know take pictures or use labeled pieces of paper to ensure they track the exact order in which they uninstalled the various carb components.
- There are numerous ways to clean a carburetor, with manufacturer-recommended carb cleaner products and ultrasonic immersion solutions.
- Rebuilding your detailed-cleaned carburetor will likely require fresh gaskets.
Finally, we suggest consulting the service manual for your make and year model moto, as carbs can vary in design.
7. Clogged Fuel Injectors
Modern motorcycles use computer-managed fuel injection systems rather than carburetors, which require less maintenance and upkeep. That said, a bike with a clogged fuel injector will crank over but take a long time to start, as there won’t be any combustion.
This is one of the least common items on the list, and if your injector is the reason for your moto’s delayed startups, it’s only a matter of time before it won’t start at all.
- A clogged injector typically happens on bikes after they sit unused with old fuel in the tank.
- As the fuel degrades, it starts to thicken.
- When you go to fire up your motorcycle, the fuel deposits in the tank make their way into the filter, and the fuel in your lines clogs your injectors, narrowing the fuel supply and prolonging the time it takes for your motorcycle to start.
- Eventually, the clog will get bad enough to prevent fuel from passing into the combustion chamber, and your motorcycle won’t start.
8. Faulty Starter
Your motorcycle’s starter is made of 3 primary components.
- The relay transfers power from the battery to the starter.
- The solenoid is the magnet that surges to crank the starter motor.
- The third component is responsible for cranking your flywheel and starting the bike.
Therefore, a failing motorcycle starter can cause different starting problems depending on which part is worn. You may experience a coughing, buzzing, or whirring starter that struggles to start your motorcycle for a long time before finally starting.
Eventually, the bike will fail to start altogether as the parts wear out. Depending on where the starter is most worn, the motorcycle fails to start immediately without any strange sounds.
Regardless of which starter components fail, the starter unit must be replaced to get your motorcycle starting immediately without staggering.
Please also read our article on how to start a motorcycle with a bad starter.
9. Worn Ignition Coil
A worn ignition coil hinders your motorcycle’s spark circulation, causing it to take longer to start up than usual. If a faulty ignition coil is a reason your motorcycle takes too long to start, once it does start, you’ll notice it frequently stalls out.
Eventually, your bike will stall as soon as it starts until it fails to turn over completely.
- A motorcycle’s ignition coil is worn from engine heat and vibration.
- Routine ignition system inspection prevents starting, running, and performance problems.
- Fortunately, an ignition coil replacement job is quick, easy, and inexpensive for any decent moto mechanic.
10. Weak Spark Plug
A weak spark plug won’t arch like a fully functional one, and your bike will take longer and longer to start until you replace it.
11. Freezing Ambient Temperature
Some motorcycles take a long time to start up when the temperature is cold, significantly if the battery, spark plugs, ignition coil, or wires are already compromised, as cold weather taxes their power supply.
13 Reasons Why Your Motorcycle Won’t Start And How To Fix It | Motorcycle Habit