Motorcycle won't start: work the checklist

Around 80% of no-starts are the battery or a safety interlock — the kill switch, the side-stand switch, the clutch or neutral switch. So before a single tool comes out: run switch to run, bike in neutral, clutch pulled in, side stand up, ignition fully on. That sequence has revived more dead motorcycles than any multimeter, and it costs ten seconds.

The embarrassing checks first

Work through these in order, every time, even when you are sure:

• Kill switch at run. It gets knocked by gloves, covers, and passers-by more often than anyone admits.
• Neutral selected, green light on. Many bikes refuse to crank in gear with the stand down.
• Clutch pulled in anyway — some bikes require it regardless of gear, and neutral switches lie.
• Side stand up if the bike is in gear.
• Ignition on, steering unlocked, and enough fuel that the gauge is not guessing.
• Keyless or immobiliser bikes: a flat fob battery produces exactly this symptom. Hold the fob against the ignition area and try again.

There is no shame in any of these — and the switches themselves fail, too. A corroded side-stand switch is a classic source of a bike that starts, then dies the moment first gear is selected.

Listen to what it does

What happens when you press the starter button splits the diagnosis cleanly. Match the sound, then run the test.

What happens	Points to	First test
Nothing, dash dead	Battery, main fuse, or terminals	Check terminals and the main fuse
Dash lives, button does nothing	Interlock or starter circuit	Repeat the interlock sequence, listen for the relay
One firm click	Flat battery, relay, or ground strap	Measure battery voltage
Rapid clicking	Battery nearly flat	Charge before anything else
Cranks slowly	Weak battery, or cold thick oil	Charge fully, then retest
Cranks well, no fire	Fuel or spark	Listen for the pump prime, then check a plug

Silent or clicking: the electrical side

A rested battery should read 12.7 V or better; below 12.4 V, charge it before cranking again — cranking a low battery flattens it further and proves nothing. The full numbers, and the case for a maintainer, are in the battery care guide. While the meter is out, check that the terminals are tight and clean, then follow the negative lead to the frame or engine: a corroded ground strap gives the classic one-click-and-nothing even with a healthy battery.

A completely dead dash with a good battery means the main fuse — find it near the battery or the starter relay, and check the spare clipped beside it is actually present before you need it in the dark. And if the fault comes and goes with a wiggle of the kill switch, the switch contacts have corroded; a shot of contact cleaner into the switch housing is a legitimate five-minute repair on a bike that lives outdoors.

If charging fixes it today but the bike is dead again next week, stop replacing batteries and find out why — the charging-system triage splits a bad battery from a parked drain from a bike that is not charging at all.

Cranks but will not fire: fuel, then spark

Fuel first, because it is easier to check. Switch the ignition on and listen: an injected bike primes its pump for about two seconds — a hum from under the tank. No hum means the pump, its relay, or its fuse, and on many bikes the kill switch also cuts the pump circuit, so check it again. Carburetted bikes: petcock to ON or RES, and consider whether fuel is actually reaching the bowls. A bike that has sat for months adds stale petrol to the suspect list — varnished carb bowls after a lay-up are their own subject, covered in the spring start-up checklist.

On a carburetted bike, remember the enrichener before condemning anything: a cold engine without the choke on may simply refuse, and that counts as a fuel-delivery fault you fix with your left hand.

Spark next. Pull an accessible plug, refit it to its cap, hold the threads firmly against bare engine metal — with insulated pliers, not fingers, unless you enjoy the ignition system's opinion of you — and crank: you want a crisp blue spark, not a lazy orange one. No spark with a good battery points at caps, coils, or the plugs themselves — worn plugs make starting hard long before they fail outright. Note also that five failed start attempts can flood the engine and soot the plugs, so the bike may now have two problems: the original one, and wet plugs that need drying or replacing before anything else can be proven.

When to stop cranking

Crank in bursts of a few seconds with rests between, never long continuous grinds — starter motors overheat, batteries empty fast, and unburned fuel washes the cylinders. If two or three passes through the checklist have not found the fault, stop. Every extra minute of hopeful cranking adds a flat battery, a flooded engine, and a hot starter to whatever was actually wrong, and turns one diagnosis into three. Charge the battery fully, come back with the symptom table, and work it in order — or have the bike collected. A no-start is an inconvenience; a no-start with three self-inflicted faults on top is an afternoon.