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- Title
- Spark Plugs 101: Copper vs Iridium and When to Replace Them
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spark-plug-copper-vs-iridium- Tags
- Maintenance, Ignition, Spark Plug
- Excerpt
- It's small, it's cheap, and it can make your bike hard to start. Here's how spark plugs work, when to change them, and whether iridium is worth it.
- Meta description
- Spark plug guide: copper vs iridium, replacement intervals, signs of a worn plug, and how to choose the correct plug for your motorcycle.
- Featured image
- A new spark plug next to a worn, sooty one — close-up. 1200×800px.
Spark Plugs 101: Copper vs Iridium and When to Replace Them
Replace a standard copper plug every 5,000–10,000 km. An iridium plug lasts 20,000 km or more and starts easier — just make sure you buy the correct plug for your bike.
The spark plug is one of the smallest and cheapest parts on your motorcycle — and one of the most important. A worn plug quietly costs you fuel, smooth starts and power long before it fully fails.
Here is everything a rider needs to know, without the jargon.
What a spark plug does
The spark plug screws into the top of the cylinder head. Its job is simple but vital: deliver a high-voltage spark at exactly the right moment to ignite the air-and-fuel mixture inside the engine. Every power stroke your engine makes starts with that spark.
Signs your plug is worn out
A tired spark plug usually shows itself like this:
- Hard starting — the engine cranks longer than usual before catching.
- Misfires or hesitation — a stumble when you open the throttle.
- Rough idle — the engine feels uneven at a standstill.
- Worse fuel economy — you notice fewer kilometres per tank.
- Weaker pull — a general loss of crispness and power.
If you pull the plug and the tip is sooty black, oily, or the electrode looks rounded and eroded, it has done its time.
Copper vs iridium: what's the difference?
The main difference is the centre electrode material, and it affects both lifespan and how the plug performs.
| Copper (standard) | Iridium | |
|---|---|---|
| Lifespan | 5,000–10,000 km | 20,000 km and beyond |
| Starting | Standard | Faster, easier — especially cold starts |
| Burn efficiency | Good | Finer electrode, more efficient spark |
| Price | Low | Higher, but lasts much longer |
| Best for | Budget upkeep, frequent changers | Riders who want longer service and easy starts |
Iridium plugs cost more up front, but spread across their long life they are excellent value — and many riders simply enjoy the quicker, more reliable starts. Platinum plugs sit in the middle if you want a step up from copper without going all the way to iridium.
A spark plug must match your engine's heat range and thread size. Buying the wrong plug — even a premium one — can cause poor running or engine damage. Always order the correct plug for your specific model.
The easiest DIY job on your bike
Changing a spark plug is one of the most beginner-friendly maintenance tasks there is. You need a plug socket and a few basic tools. Remove the cap, unscrew the old plug, check the gap on the new one against your bike's spec, and thread it in by hand before tightening — never force it.
A fresh plug is a small spend that pays you back every time you press the starter.
Spark plugs for every popular Yamaha, Honda and Suzuki model — genuine parts, shipped from our Philippine warehouse in 1–3 days, with Cash on Delivery available.
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