What are Spark Plugs?
Small igniters threaded into the cylinder head that spark to set the fuel-air mixture alight.
Simplified animation — not to scale.
In plain English
Each cylinder has a spark plug that fires a high-voltage spark across a tiny gap, igniting the compressed fuel-air mixture at exactly the right moment to drive the piston down.
“Like the flint in a lighter, except it strikes precisely in time with the engine, up to a hundred times a second at high revs.”
How it works
The ignition coil turns 12 volts into tens of thousands of volts, sent to the plug at the top of the compression stroke. The spark jumps the gap between the electrodes and ignites the mixture. Worn electrodes or a fouled tip create a weaker, less reliable spark.
Signs of trouble
- ⚠Rough idle or a noticeable misfire
- ⚠Hesitation or flat spots under acceleration
- ⚠Harder starting, especially from cold
- ⚠Poor fuel economy
What affects the repair?
We don't publish a generic price for this part because a responsible estimate needs a named motorcycle and a recent quote. These are the factors a qualified technician will weigh up.
- •Diagnosis: intermittent or system-wide faults may need dealer-level tools before the actual part can be identified.
- •Accessibility: some parts are quick to reach; others require significant fairing, tank or engine-cover removal.
- •Model differences: prices and labour times vary widely between manufacturers and specification levels.
- •New vs used: a genuine OEM part fitted at a franchised dealer costs more than a serviceable used or aftermarket part.
- •Calibration / coding: some parts require post-fit calibration, coding or a road test, which adds labour time.
Technical review pending