06/01/2020
There's nothing quite like the disheartening click, or worse, the complete silence, when you press the starter button on your beloved motorcycle and nothing happens. A flat battery is a common culprit, often catching us off guard. While a charger is the ideal solution, sometimes time or circumstances simply don't allow for it. This is where the age-old technique of 'bump starting' or 'push starting' comes into its own – a physical, hands-on method to coax your engine back to life. It’s a bit of an effort, but a rewarding one when your bike fires up. But before you start pushing, let's explore when and how to do it safely and effectively, and what to consider if it doesn't quite go to plan.
When Your Battery Says 'No!': Deciding If a Bump Start Is Right
Bump starting isn't a magical cure-all, and it certainly isn't a pleasant way to spend your morning. It requires effort, and sometimes, a fair bit of sweat. So, before you commit to pushing your bike down the street, it's crucial to ascertain if a flat battery is indeed the problem, and if a bump start is even feasible for your particular situation.
Initial Checks: The Non-Negotiables
Before you even think about breaking a sweat, make sure you've ruled out the simplest, most embarrassing causes. Many a rider has pushed their bike for metres only to realise a silly oversight. Always double-check:
- Is the kill switch in the 'run' position? This is, by far, the most common reason for a failed start and a source of much frustration.
- Is the sidestand up? Many modern bikes have a safety cut-off that prevents starting if the sidestand is down, especially when in gear.
- Is the bike in neutral, or if in gear, is the clutch pulled in? Some bikes require the clutch to be engaged even in neutral. Triumph and Suzuki owners, specifically, often need to pull the clutch in to start, regardless of gear.
- Is there sufficient fuel? An empty tank is just as effective at preventing a start as a dead battery.
Diagnosing the Culprit: Is It Truly the Battery?
Bump starting works by using the momentum of the bike to turn the engine over, simulating the action of the starter motor. This replaces the electrical power needed to crank the engine. Therefore, it will only work if the battery is the primary issue. If your bike was running perfectly yesterday but is completely lifeless today, the battery might be the problem. However, consider these scenarios:
- If your lights are blazing bright, and the horn sounds strong, but the engine simply won't turn over, the issue is likely with the starter motor itself, or a faulty relay, not necessarily the battery.
- If you were tinkering with electrical connections (like a sat-nav) recently and the bike is now dead, double-check those connections. A loose terminal can mimic a dead battery.
- If the bike is totally dead – no lights, no dashboard illumination, absolutely nothing – a bump start is unlikely to work. The engine still requires a small amount of electrical power to generate a spark and power the fuel pump and ECU (Engine Control Unit). If there's no residual power, there's no spark, and no start.
Battery Life: A Glimmer of Hope
For a bump start to be successful, there needs to be at least a little life left in the battery. You'll typically see some faint glow from the dashboard lights, or perhaps a weak headlight beam. This indicates enough power for the ignition system to fire once the engine begins to turn. If the battery is completely flat, with no electrical activity whatsoever, the bike's electronics (ECU, ignition coils) won't have the necessary juice to operate, rendering a bump start futile.
Not All Bikes Are Created Equal
A crucial point: bump starting relies on a manual gearbox to engage the engine with the road's momentum. This means:
- You cannot bump start a scooter, as they typically use an automatic, continuously variable transmission (CVT).
- You cannot bump start a Honda DCT (Dual Clutch Transmission) equipped bike, as these are also automatic.
Bump starting is exclusively for motorcycles with a traditional manual transmission.
Location, Location, Location: Finding the Perfect Spot
Once you've determined a bump start is your best bet, the next step is finding a suitable location. Safety and practicality are paramount.
- Safety First: Avoid busy roads. The last thing you need is to be distracted by traffic or, worse, involved in an accident. If you're on a main road, push the bike to a quieter side street or a car park if possible. Never attempt this on a pavement where pedestrians might be present; it's dangerous and potentially illegal.
- Seek a Slope or an Assistant: A gentle downhill slope is your best friend when bump starting. Gravity does a lot of the hard work, allowing you to build momentum more easily. If a slope isn't available, a friend or two who can push the bike for you will make the process infinitely easier.
- Clear Road Ahead: You'll need at least 50 metres of clear, unobstructed road ahead of you. This gives you enough space to build speed, attempt the start, and then safely bring the bike to a halt if it doesn't catch immediately. Avoid areas with potholes, loose gravel, or obstacles.
The Art of the Push: A Step-by-Step Guide to Bump Starting
With your location sorted and your bike deemed a candidate for a bump start, it's time to get down to business. Follow these steps carefully to maximise your chances of success:
Pre-Flight Checks (Again!)
Turn the ignition on. Seriously, do it. And then, run through all those basic checks mentioned earlier: kill switch on, sidestand up, bike in gear (or ready to be). The kill switch is the most common reason for failure, so double-check it!
Choke On (If Applicable)
If your bike has a manual choke, set it to the position you'd normally use for a cold start. This enriches the fuel mixture, aiding combustion, especially if the bike hasn't run for a while.
Gear Selection and Clutch Engagement
Put the bike into second gear. For most motorcycles, second gear provides the best balance between resistance and the ability to turn the engine over. If you're on a high-powered sportsbike with a very tall first gear, you might find first gear works better. Pull the clutch lever all the way in. If your bike has significant clutch drag (where the clutch doesn't fully disengage even when pulled in), you might consider starting in neutral and then knocking it into gear just before you drop the clutch. However, this adds complexity and is generally not recommended for beginners.
Here's a quick guide for typical gear selection:
Motorcycle Type Recommended Gear Notes Standard/Naked Second Gear Good balance of momentum and engine turning. Cruiser/Tourer Second Gear Heavy bikes benefit from sustained momentum. Sportbike First or Second Gear Tall first gear might work, otherwise second. Off-road/Dirt Bike Second Gear Often easier to get momentum. Build Momentum: The Sprint
This is where the physical effort comes in. If you're alone, you need to sprint alongside the bike. Hold the handlebars firmly, lean the bike slightly towards you for better control, and run as fast as you can. For larger, heavier bikes, this can be quite a workout. If you have an assistant (or several), get them to push the bike while you're already seated on it. This allows for a more controlled and often faster build-up of speed.
The Critical Moment: Hop and Pop!
Once you've built up a decent running speed (think a brisk jog to a full sprint), swiftly put your left foot onto the left footpeg (being careful not to accidentally hit the gear lever). In one fluid motion, hop onto the saddle and, simultaneously, snap the clutch out. Do not 'feather' or slowly release the clutch; this will just cause the rear wheel to drag and act as a brake, preventing the engine from turning over. The sudden engagement of the clutch uses the momentum of the rear wheel to force the crankshaft to spin. Timing your bum hitting the saddle with the clutch release can add extra downward pressure, enhancing rear wheel traction.
Resist the urge to give it a handful of throttle unless your bike specifically requires it for starting. A small, steady amount of throttle, or none at all, is usually best.
The 'Pop Start' - Don't Linger!
Almost immediately after the engine (hopefully) catches, pull the clutch back in again. This is why Americans often call it a 'pop start' – you're popping the clutch in and out quickly. If the engine fires and you leave the clutch out, you risk the bike lurching forward, possibly on full choke, or stalling if the engine doesn't quite catch properly. By pulling the clutch back in, you regain control and allow the engine to stabilise. If it doesn't catch, you can repeat the 'pop' action multiple times as you continue to roll, giving you multiple bites at the cherry without having to stop and push again.
Engine Caught? Stabilise!
If the engine catches, fantastic! Keep the clutch in and allow the engine to stabilise. Gently apply throttle to keep the revs up, especially if it's a cold start and the choke is on. Let it warm up as you normally would. The most important thing now is: don't stall the bloody thing!
The Agostini Manoeuvre (Advanced/Risky)
For those feeling particularly daring, or if the bike is proving stubborn, you can attempt to jump on 'side saddle' – straddling the bike from the side while running alongside it. This allows you to easily jump off again to push for more speed if the engine doesn't catch in the first few pops. It looks cool, like a GP rider from the 1960s. However, be warned: if the bike suddenly grinds to a halt (common with high-compression singles or some Ducatis), there's a significant chance you and the bike will topple over to the right. This will definitely dent your Agostini vibe and potentially your bike.
If you’re got a glow from the lights and all warning lights in the clocks come on, a bump start will probably work. If the battery is completely dead, it probably won’t. You’re not riding a scooter or Honda DCT-equipped bike. You can’t bump an auto gearbox. Where should I bump start a motorcycle? Three things to consider here: Is it safe? Beyond the Battery: When Bump Starting Fails
So, you've pushed, you've popped, you've probably sworn a bit, and still, your bike stubbornly refuses to start. If you could previously bump start your bike, but now it won't even respond to this method, the problem likely lies beyond just a flat battery. An engine needs three fundamental elements to run: Fuel, Air, and Spark. If any of these are missing or compromised, the engine won't fire.
1. Spark Issues
The spark ignites the fuel-air mixture. If there's no spark, there's no combustion.
- Spark Plugs: These are the first things to check. Remove them and inspect their condition. Are they fouled with carbon deposits, oil, or fuel? Are the electrodes worn or damaged? A dirty or faulty spark plug can prevent a strong spark. Replace them if necessary. Even if they look okay, if they're old, they might not be performing optimally.
- Ignition System: Less common, but issues with the ignition coils, spark plug leads, or the CDI/ECU unit can prevent spark. This usually requires professional diagnosis.
2. Fuel Issues
Without the correct amount of fuel, the engine won't run.
- Fuel Level: Yes, it sounds obvious, but ensure there's enough fuel in the tank.
- Fuel Delivery: Is fuel reaching the engine? Check the fuel tap (if manual) to ensure it's on. For carburetted bikes, the issue often lies within the carburettors themselves.
- Carburettor Problems: Over time, fuel can leave deposits, blocking tiny passages and jets. If your bike has been sitting for a while, especially with old fuel, the jets (particularly the pilot jet) can become obstructed.
- Jets: These small, precisely drilled brass fittings control fuel flow. If clogged, the engine won't get enough fuel. Cleaning them often involves removing the carbs, disassembling the float bowls, and carefully clearing the jets, sometimes with pressurised air or fine wire.
- Float Bowls: These hold a small reservoir of fuel for the carburettors. They can accumulate debris or old, varnished fuel. Draining and cleaning them is a good practice.
- Fuel Pump (Fuel-Injected Bikes): If your bike is fuel-injected, listen for the whirring sound of the fuel pump priming when you turn the ignition on. If you don't hear it, the pump might be faulty, or there could be an electrical issue preventing it from operating.
3. Air Issues
The engine needs a precise amount of air mixed with fuel for combustion.
- Air Filter: A severely clogged air filter can restrict airflow, making it hard for the engine to breathe. While less likely to cause a complete no-start, it can contribute to poor running.
- Valve Clearances: This is a more advanced check, but crucial for single-cylinder bikes, especially after significant mileage (around 30,000km or as per manufacturer's schedule). Engine valves need a precise gap, or 'clearance', to operate correctly. If these clearances become too tight due to wear, the valves may not close fully, leading to a loss of compression. Without good compression, the engine won't be able to draw in enough air or create the pressure needed for combustion. Checking and adjusting valve shims (small metal discs that set the clearance) is a precise job and often requires specialist tools or a mechanic. You can find bike-specific tutorials online, but it's not for the faint-hearted.
Frequently Asked Questions (FAQs)
Q: Can I bump start a motorcycle with a completely dead battery?
A: Generally, no. While bump starting bypasses the starter motor, the bike still needs a small amount of residual battery power to operate the ignition system (spark plugs, ECU) and the fuel pump (on fuel-injected models). If there's absolutely no power, no dash lights, nothing, a bump start is unlikely to work.
Q: What gear is best for a bump start?
A: Second gear is typically recommended for most motorcycles. It offers a good balance between the resistance needed to turn the engine over and the ability to build sufficient road speed. For some high-performance sports bikes with very tall first gears, first gear might also be an option.
Q: Is bump starting bad for my motorcycle engine?
A: While not ideal as a regular starting method, bump starting occasionally in an emergency is generally not harmful to your engine. The primary concern is the sudden shock to the drivetrain when you snap the clutch out. Doing it incorrectly or too aggressively could put stress on the clutch, gearbox, or chain. However, a properly executed bump start for an emergency won't cause significant damage.
Q: What if the engine starts but then dies immediately?
A: This suggests the issue is more than just a flat battery. It could indicate a problem with the fuel supply (clogged fuel filter, faulty fuel pump, dirty carburettor jets), a weak spark, or an air intake issue (like incorrect valve clearances). The engine is getting just enough to fire briefly but can't sustain itself. In this scenario, you'll need to investigate the fuel, air, and spark systems as detailed above.
Q: How can I prevent my battery from going flat again?
A: Regular battery maintenance is key. Use a trickle charger or battery tender if your bike is stored for extended periods, especially during cold weather. Ensure your battery terminals are clean and tight. If your battery frequently goes flat, it might be old and no longer holding a charge effectively, or there could be an issue with your bike's charging system (e.g., faulty stator or rectifier/regulator). In such cases, professional diagnosis is recommended.
Bump starting a motorcycle is a useful skill to have in your mechanical arsenal. It can get you out of a tricky situation when a flat battery strikes unexpectedly. However, remember it's a temporary solution. If your battery is constantly draining, or if your bike consistently requires a bump start, it's a clear sign that there's an underlying issue that needs professional attention. Don't rely on it as a long-term fix; instead, use it as a means to get home and diagnose the root cause of your starting troubles.
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