BMW Motorrad makes some of the most refined, luxurious, and unique motorcycles in the game.
That said, there’s been no shortage of reliability complaints about the models over the year.
This article explores the most common reasons why BMW motorcycles won’t start.
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Here’s Why your BMW Motorcycle Won’t Start:
There are many possible reasons why your BMW motorcycle won’t start, but some of the most common causes are related to the battery, the starter motor, the fuel system, and the spark plugs. If your electrical system is faulty, you may need more power to crank your BMW engine.
BMW Motorcycle Won’t Start
Here are some of the most common reasons BMW Motorcycles have starting problems.
Kill Switch Set to OFF
Every now and then, even expert-level riders accidentally flick their run switch into the OFF position while mounting their BMW motorcycle.
Setting your ignition switch to KILL or OFF cuts power off to the ignition system. In an emergency, the switch immediately kills the energy flowing to the engine. But unless your kill switch is set to RUN or ON, your motorcycle won’t start.
Petcock
Older BMW models used a device called a petcock, a valve that controls the fuel flow from the tank to the carburetor. When set to the OFF position, a petcock can cause vintage BMW motorcycles not to start by preventing fuel from reaching the engine.
- Check if the petcock is in the correct position (ON or RESERVE) and not in OFF.
- Clean the petcock and filter screen with carburetor cleaner or compressed air.
- Replace the petcock gasket or O-ring if it is worn or damaged.
- Replace the petcock if it is cracked, corroded, or stuck.
Side Stand Extended
Some BMW motorcycles have a safety feature that prevents the engine from starting if the side stand is down to avoid the risk of the bike jumping forward or falling over when the rider engages the clutch or shifts into gear.
However, if the side stand is extended or modified to be longer than the original, it may not activate the switch that tells the bike that the stand is up, causing the bike’s ECU to think that the stand is always down and refuse to start.
To fix this problem, the rider may need to adjust or replace the side stand switch or shorten the side stand to its original length.
In other scenarios, the side stand sensor gets blocked or damaged by road debris and thinks the stand is down when it isn’t.
First, try cleaning the dirt, moisture, corrosion, and debris off the sensor located on the frame near the side stand.
If cleaning the debris doesn’t get your BMW started, the next step is to check the sensor’s voltage, replacing the sensor if it’s faulty.
BMW Motorcycle Won’t Start Just Clicks
If your BMW won’t start and you hear a clicking noise when you turn the key or push the start button, it usually means that your battery is dead or low. The clicking noise is the starter motor attempting to turn the engine over without having enough power.
To confirm that your battery is the reason our BMW motorcycle won’t start but clicks, check the battery voltage with a multimeter or a voltmeter.
If you confirm your battery isn’t why your BMW motorcycle clicks instead of starting, the next likely culprit is your starter system.
- A faulty starter motor or solenoid: If either of these components is defective, they may not start your bike correctly and cause a clicking noise as they shed electrical current.
- A poor electrical connection between the battery and the starter motor: If there is any resistance or interruption in the circuit, such as a loose or corroded wire, a blown fuse, or a bad relay, the starter motor may not receive enough power and make a clicking noise.
- A bad ground connection between the engine and the chassis: If this connection is loose, corroded, or broken, it may cause a voltage drop and affect the starter motor’s performance.
BMW Motorcycle Won’t Start in Gear
Your BMW motorcycle might not start in gear due to a faulty clutch sensor, side stand sensor, neutral sensor, or starter motor.
Sensor switches are safety devices or components that communicate with the ECU to cut power if they detect a problem.
Here are some possible problems/solutions for a BMW motorcycle that won’t start when in gear for this issue:
- Clutch sensor: Clean or replace it if it’s dirty or broken.
- Side stand sensor: Bypass or replace it if it’s defective.
- Neutral sensor: Adjust or replace it if it’s worn out.
- Starter motor: Tap or replace it if it’s weak or jammed.
You can often get your Motorrad bike to start by cleaning, adjusting, bypassing, or replacing these components as needed, depending on the problem.
BMW Motorcycle Won’t Crank
If your BMW motorcycle doesn’t crank when you press the start button, it could be due to a problem with the battery, the starter motor, the ignition system, or the fuel system.
Here are some possible causes and solutions for a BMW motorcycle that won’t crank:
- Battery: Check the battery voltage with a multimeter. It should be close to or slightly above 12 volts. If it’s low, charge it or replace it if it’s dead.
- Starter motor: Check the starter motor for any signs of damage or corrosion. Tap it with a hammer or wrench to free it up if it’s jammed. Replace it if it’s weak or faulty.
- Ignition system: Check the fuses and relays for the ignition system. Make sure they are not blown or loose. Check the spark plugs and wires for any signs of wear or damage. Replace them if necessary.
- Fuel system: Check the fuel pump and filter for blockages or leaks. Make sure the fuel pump is priming when you turn on the ignition. Check the fuel pressure with a gauge at the end of the fuel line. Replace any faulty parts if needed.
Related: Are BMW Motorcycles Worth the Money? (Reviewed)
BMW Motorcycle Won’t Start After Laying Down
If your BMW motorcycle doesn’t start after a fall or drop, it could be due to one of these reasons:
- Tip-over sensor: Component that shuts off the engine and fuel pump when the bike falls over, preventing fuel leakage and fire hazards. To reset it, you need to turn off the ignition and turn it back on after 1-5 minutes.
- Flooded carburetor: Too much fuel enters the engine cylinders and prevents combustion. It can occur when the bike lays down, and the fuel flows out of the carburetor. To fix it, let the bike stand until the excess fuel drains and evaporates, or open the throttle fully and crank the engine several times.
- Disconnected electronics: The fall causes some wires or connectors to come loose or break, affecting the battery, ignition system, fuel system, or starter motor. To fix it, inspect the wiring and connections for any signs of damage or disconnection; check the fuses and relays for any blown.
BMW Motorcycle Won’t Start After Winter
If your BMW motorcycle doesn’t start after winter, it could be due to one of these reasons:
- Dead battery: The battery may have lost its charge over the winter due to cold temperatures or parasitic drains. Try jump-starting your BMW or replacing the battery if it’s old or damaged¹².
- Bad fuel: The fuel in your BMW may have gone bad over the winter due to oxidation or contamination. Try draining and replacing the degraded fuel, adding fresh fuel, or a fuel stabilizer to your BMW after.
- Clogged fuel system: The fuel system may have become clogged over the winter due to dirt, debris, or moisture in the fuel lines, filter, pump, or injectors. Try cleaning or replacing any dirty or faulty fuel system components.
- Faulty spark plugs: The spark plugs may have worn out over the winter due to corrosion or carbon buildup. Try replacing old, worn, or damaged spark plugs with new ones if your BMW motorcycle won’t start after storing it for winter.
BMW Motorcycle Won’t Start Oil Light On
Here are the most common reasons why a BMW motorcycle won’t start when the oil light is on:
- Low oil level: The oil light may indicate that the oil level is too low for the engine to operate safely. Check the oil level with the dipstick or the sight glass; add more oil if needed.
- A Faulty oil pressure switch can trigger the oil light even when the oil level and pressure are average, preventing the engine from starting as a safety measure. Test the switch with a multimeter; replace it if it’s defective.
- A faulty oil pump might not deliver enough oil pressure to the engine, causing the oil light to come on and the BMW bike won’t start. Check the oil pressure with a gauge; replace the pump if worn out or damaged.
BMW Motorcycle Won’t Start When Hot
If your BMW motorcycle doesn’t start when it’s hot, it could be due to a weak battery, a faulty starter motor, or a failing ignition system.
- Weak battery: The battery may lose its charge faster when it’s hot, especially if it’s old or damaged.
- Faulty starter motor: The starter motor may overheat and fail when hot, especially if worn out or corroded.
- Failing ignition system: The ignition system may malfunction when it’s hot, especially if there are loose or damaged wires, connectors, coils, or spark plugs.
BMW Motorcycle Won’t Start After Changing Handlebars
A common reason your BMW motorcycle won’t start after changing handlebars is from accidentally disconnecting or damaging the clutch sensor switch, as it connects to the handlebars.
Your clutch sensor prevents the starter motor from starting in gear unless you pull the clutch lever.
If you recently changed your BMW Moto’s handlebars and now it won’t turn over, check the wires and connectors of the switch or try to short across it or ground it to bypass it. You should also check the ignition fuse.
BMW Motorcycle Won’t Start With Key Fob
The most common reason a BMW motorcycle won’t start with the key fob is that the key fob battery is dead or the key fob is damaged. Furthermore, keeping your fob in your pocket with metal can interfere with its signal, causing your ECU to read the fob as out of range, even if it’s close.
- Try using the emergency key that comes with the key fob to unlock and start your BMW.
- Some BMWs allow the rider to input codes to bypass the fob.
- Finally, try replacing the fob’s battery or get a new key fob from the dealer.
BMW Motorcycle Won’t Start With New Battery
If your BMW motorcycle won’t start and you know you have a new battery, you may have a faulty charging system or starter motor.
Motorcycles use parts called Stators and Regulators/Rectifiers to recharge the battery while you ride and power the electrical system. Your BMW’s starter motor is responsible for cranking the engine at start-up.
- If any of your BMW’s charging or starter system components or starter fail, your motorcycle won’t start. Inspect the charging system and starter using a multimeter and listen for unusual noises.
BMW Motorcycle Won’t Start with Clutch Pulled
A common reason why BMW motorcycles won’t start with the clutch lever pulled in is due to a faulty clutch sensor or worn clutch lever or cable.
The clutch switch is a safety device that prevents the motorcycle from starting in gear unless the clutch lever is pulled.
- The clutch switch may not send the signal to the starter relay if it’s worn or damaged. You can check the clutch switch using a multimeter and clean or replace it.
- A frayed or worn clutch cable causes similar symptoms, like incomplete disengagement, lurching, and staling out, but starting problems are more likely the clutch sensor switch than the cable.
- Finally, if the clutch lever is broken, loose, or misaligned, it may not pull the clutch cable or switch properly, causing the motorcycle to not start in gear or stall or lurch when put in gear.
BMW Motorcycle Won’t Start Lights Flashing
If your lights are flashing at startup, one possible reason why your BMW motorcycle won’t start is that the ignition system fails to recognize the key. This can happen if the key battery is dead, the key is damaged, or the key hasn’t been programmed correctly.
You’ll know this is the culprit if you see a key symbol on your BMW’s dash display.
You can try to use another key, replace the key battery, or have the dealership reprogram your key with the official BMW tool.
Related: How Long Do BMW Motorcycles Last? (Solved & Explained)
